Search

This study explored the self-reported prevalence of cardiovascular disease (CVD) and accompanying risk factors among 165 male retirees 43 years and older (M = 56.2, SD = 7.1) from the Milwaukee Police Department (MPD) compared to 671 individuals of similar age and income who responded to the 2005 Wisconsin Behavioral Risk Factor Surveillance System (BRFSS). CVD and other risk factors were more prevalent in the MPD retirees than the general population (CVD 15.2% vs. 9.5%, p = .036; hypertension 51.5% vs. 36.2%, p = .001; hypercholesterolemia 62.4% vs. 44.4%, p = .001; overweight and obesity 85.1% vs. 74.7%, p = .005). In addition, other factors associated with CVD prevalence included working in law enforcement (odds ratio = 1.70; 95% confidence interval = 1.03 to 2.79). Results suggest an association between employment in law enforcement and an increase in CVD morbidity. [ABSTRACT FROM AUTHOR]

This cross-sectional study determined the prevalence of nephrolithiasis and common cardiovascular disease (CVD) risk factors in a law enforcement officer (LEO) cohort and evaluated the relationship of nephrolithiasis with several CVD risk factors, including the possible effect of ethnicity. Self reported nephrolithiasis and CVD risk factors among currently employed male LEOs from nine states (n = 2,818) were compared to other men in the same states (n = 9,650). Of the LEOs, 6.2% (n = 174) self reported at least one kidney stone (range = 1 to 12, mean 2.3 6 2.1 stones). Twenty five percent of Native American LEOs (n = 7 of 28) self reported a history of stones. In LEOs with a history of nephrolithiasis, overweight defined as body mass index . 25 kg/m2 (odds ratio [OR] = 1.80, 95% confidence interval [CI] = 1.04, 3.11), hypercholesterolemia (OR = 1.53, 95% CI = 1.09, 2.15), and hypertension (OR = 1.46, 95% CI = 1.02, 2.11) were associated with the disease. These results suggest officers with common CVD risk factors are also at an increased risk for nephrolithiasis. Native American LEOs have a disproportionately higher prevalence of nephrolithiasis than do other ethnic groups. [ABSTRACT FROM AUTHOR]

It is unclear to what extent law enforcement officers (LEOs) experience increased prevalence of cardiovascular disease (CVD; defined as coronary heart disease, myocardial infarction, angina, or stroke) and, if so, whether perceived stress affects this relationship. First, self-reported CVD risk factors among currently employed male LEOs from 9 states (n = 2818) were compared to CVD risk factors among similarly-aged males with similar incomes in the same states (n = 8046). Second, CVD prevalence was compared among LEOs (n = 1791) and similarly-aged males with similar incomes (n = 2575) from four of these states. Finally, among the LEOs only, the possible effect of perceived stress on the relationship between CVD prevalence and CVD risk factors was assessed. LEOs reported higher prevalence of hypertension, hypercholesterolemia, tobacco use, and elevated body mass index. CVD prevalence did not differ significantly between the LEO group and the general population (2.3% +/- 15% versus 3.1% +/- 17%; P = 0.095). In the LEO-only group, the best predictors of CVD were: time in the profession (OR = 1.07; 95% CI = 1.03-1.11), perceived stress (OR = 1.05; 95% CI = 1.00-1.10), and hypertension (OR = 0.33; 95% CI = 0.18-0.62). In the LEO-only group, perceived stress was associated with CVD (P = 0.008), and three CVD risk factors were significantly affected by perceived stress: cholesterol, hypertension, and physical activity. Perceived stress was affected by duration of time in the profession (P = 0.004), independent of an age effect (P = 0.353). Among susceptible officers, perceived stress may contribute to CVD directly and through potentiating several CVD risk factors. [ABSTRACT FROM AUTHOR]

Objective: To evaluate a personalized adaptive training program designed for stress prevention using graduated stress exposure., Background: Astronauts in the high-risk space mission environment are prone to performance-impairing stress responses, making preemptive stress inoculation essential for their training., Methods: This work developed an adaptive virtual reality-based system that adjusts environmental stressors based on real-time stress indicators to optimize training stress levels. Sixty-five healthy subjects underwent task training in one of three groups: skill-only (no stressors), fixed-graduated (prescheduled stressor changes), and adaptive . Psychological (subjective stress, task engagement, distress, worry, anxiety, and workload) and physiological (heart rate, heart rate variability, blood pressure, and electrodermal activity) responses were measured., Results: The adaptive condition showed a significant decrease in heart rate and a decreasing trend in heart rate variability ratio, with no changes in the other training conditions. Distress showed a decreasing trend for the graduated and adaptive conditions. Task engagement showed a significant increase for adaptive and a significant decrease for the graduated condition. All training conditions showed a significant decrease in worry and anxiety and a significant increase in the other heart rate variability metrics., Conclusion: Although all training conditions mitigated some stress, the preponderance of trial effects for the adaptive condition supports that it is more successful at decreasing stress., Application: The integration of real-time personalized stress exposure within a VR-based training program not only prepares individuals for high-stress situations by preemptively mitigating stress but also customizes stressor levels to the crew member's current state, potentially enhancing resilience to future stressors., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objectives: The aim of the study is to determine if law enforcement officers develop subclinical atherosclerotic cardiovascular disease (ASCVD) earlier than nonofficers and, if so, the extent to which conventional risk factors explain this difference. Methods: Estimated pulse wave velocity (ePWV) was the marker of subclinical ASCVD. EPWV, ASCVD risk factors, metabolic syndrome (MetS), and 10-year risk for ASCVD were compared among 408 law enforcement officers and a civilian cohort. Results: EPWV, 10-year ASCVD risk, and MetS prevalence increased significantly with age. All but the officers age 55 and older had higher ePWV cohort than the civilian cohort ( P < 0.001). Ten-year ASCVD risk explained the most variability of ePWV ( R2 = 0.49, P < 0.001). Conclusions: Officers develop subclinical ASCVD earlier than nonofficers. Conventional ASCVD risk factors only explain about half of this increase. Occupational factors may play a role in contributing to this increased ASCVD risk., Competing Interests: Conflict of interest: None declared., (Copyright © 2024 American College of Occupational and Environmental Medicine.)

Middle-aged and older adults living in rural settings have been consistently less likely to report regular physical activity (PA) than those living in urban settings. While past literature has identified sociodemographic and environmental correlates of PA that may contribute to these differences, consideration of psychological correlates has been limited. A total of 95 rural and urban adults ≥50 years old provided self-reported sociodemographic information, PA level, and psychological correlates of PA including measures assessing motivation, self-efficacy, social support, and attitudes related to PA. The average participant age was 68.6 years, and most were female (62.1%) and married (70.5%). While PA level did not differ significantly between the rural and urban groups, different psychological correlates contributed significantly to separate rural and urban linear regression models considering PA status. Among rural adults, more positive attitudes toward PA, and greater PA self-efficacy and social support were associated with greater amounts of PA while for urban adults, no psychological correlates were significantly associated with PA. Psychosocial factors may be key considerations in developing more effective PA interventions in middle-aged and older adults living in rural areas., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Sirotiak, Brellenthin, Hariharan, Welch, Meyer and Franke.)

The optimal frequency and duration of remote ischemic preconditioning (RIPC) that augments microvascular function is unknown. A single bout of RIPC increases cutaneous endothelial function for ∼48 h, whereas 1 week of daily RIPC bouts improves more sustained endothelium-independent function. We hypothesized that 3 days of RIPC separated by rest days (3QOD RIPC) would result in sustained increases in both endothelium-dependent and endothelium-independent functions. Cutaneous microvascular function was assessed in 13 healthy young participants (aged 20.5 ± 3.9 years; 5 males, 8 females) before 3QOD and then 24, 48, and 72 h and a week after 3QOD. RIPC consisted of four repetitions of 5 min of blood flow occlusion separated by 5 min of reperfusion. Skin blood flow responses to local heating ( T loc = 42°C), acetylcholine (Ach), and sodium nitroprusside (SNP) were measured using laser speckle contrast imaging and expressed as cutaneous vascular conductance (CVC = PU⋅mmHg -1 ). Local heating-mediated vasodilation was increased 72 h after 3QOD and the increased responsivity persisted a week later (1.08 ± 0.24 vs. 1.34 ± 0.46, 1.21 ± 0.36 PU⋅mmHg -1 ; ΔCVC, pre-RIPC vs. 72 h, a week after 3QOD; P = 0.054). Ach-induced cutaneous vasodilation increased a week after 3QOD (0.73 ± 0.41 vs. 0.95 ± 0.49 PU⋅mmHg -1 ; ΔCVC, pre-RIPC vs. a week after 3QOD; P < 0.05). SNP-induced cutaneous vasodilation increased 24 h after 3QOD (0.47 ± 0.28 vs. 0.63 ± 0.35 PU⋅mmHg -1 ; ΔCVC, pre-RIPC vs. 24 h; P < 0.05), but this change did not persist thereafter. Thus, 3QOD induced sustained improvement in endothelium-dependent vasodilation but was not sufficient to sustain increases in endothelium-independent vasodilation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Kim, Franke and Lang.)

Objective: High quality cardiopulmonary resuscitation (CPR) is crucial for patients experiencing cardiac arrest. CPR quality declines within the first few minutes of CPR performance. Being more fit is associated with higher CPR quality, yet the fitness parameters needed remain uncertain. It is also unknown how CPR quality is affected during a protocol of realistic CPR when rescuers switch compressors every two minutes, as recommended by the American Heart Association (AHA), and extended duration, as might be encountered with an out-of-hospital cardiac arrest. The purpose of the present study is to determine the extent to which different measures of physical fitness predict high quality CPR performance when rescuers follow current CPR guidelines. Methods: Subjects underwent a fitness assessment evaluating lower back muscular endurance, abdominal muscular endurance, upper body muscular strength, and upper body anaerobic power. At least 48 hours later, subjects returned to the laboratory for CPR testing. CPR quality was determined by compression rate (>100/minute), compression depth (>2 inches, or 50 mm), and adequate (full) chest recoil between compressions, based on American Heart Association guidelines. A CPR Quality Score, designed to represent cardiac output, was calculated as the product of compression rate and depth. Results: Thirty-three of 42 subjects were able to achieve a CPR Quality Score greater than 5000, the minimum needed to meet AHA recommendations. Higher anaerobic power and bench press scores were predictive of both high CPR Quality Scores (R 2 =0.47) and compression depth (R 2 =0.47). Sex (female) was predictive of better chest compression recoil percentages (R 2 =0.15). Conclusion: Most rescuers can maintain high quality CPR if given two minute breaks between cycles. Rescuers with high anaerobic fitness and muscular strength may be able to provide higher quality CPR.

New Findings: What is the central question of this study? Animal infarct studies indicate a delayed window of cardiac protection after remote ischaemic preconditioning (RIPC); however, the presence and duration of this delayed effect have not been examined in human microvasculature in vivo. What is the main finding and its importance? Cutaneous vasodilatation induced by local heating or ACh was increased significantly 24 and 48 h after a single bout of RIPC, respectively. Neither response persisted beyond ∼48 h. Sodium nitroprusside-induced cutaneous vasodilatation was not altered. These findings reveal a delayed increase in microvascular endothelial function after a single bout of RIPC., Abstract: Remote ischaemic preconditioning (RIPC) induces protective effects from ischaemia-reperfusion injury. In the myocardium and conduit vasculature, a single bout of RIPC confers delayed protection that begins 24 h afterwards and lasts for 2-3 days. However, the extent and the time line in which a single bout of RIPC affects the human microvasculature are unclear. We hypothesized that a single bout of RIPC results in a delayed increase in skin microvascular function. Sixteen healthy participants (age, 23 ± 4 years; seven males, nine females; MAP, 82 ± 7 mmHg) were recruited to measure cutaneous microvascular function immediately before a single bout of RIPC and 24, 48 and 72 h and 1 week after the bout. The RIPC consisted of four repetitions of 5 min of arm blood flow occlusion interspersed by 5 min reperfusion. Skin blood flow responses to local heating (local temperature of 42°C), ACh and sodium nitroprusside were measured by laser speckle contrast imaging and expressed as the cutaneous vascular conductance (CVC; in perfusion units per millimetre of mercury). Vasodilatation in response to local heating was increased 24 and 48 h after RIPC (ΔCVC, 1.05 ± 0.07 vs. 1.18 ± 0.07 and 1.24 ± 0.08 PU mmHg -1 , pre- vs. 24 and 48 h post-RIPC; P < 0.05). Acetylcholine-induced cutaneous vasodilatation increased significantly 48 h after RIPC (ΔCVC, 0.71 ± 0.07 vs. 0.93 ± 0.12 PU mmHg -1 , pre- vs. 48 h post-RIPC; P < 0.05) and returned to baseline thereafter. Sodium nitroprusside-mediated vasodilatation did not change. Thus, a single bout of RIPC elicited a delayed response in the microvasculature, resulting in an improvement in the endothelium-dependent cutaneous vasodilatory response that peaked ∼48 h post-RIPC., (© 2021 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

One week of daily remote ischemic preconditioning (RIPC) improves cutaneous vasodilatory (VD) function. However, the underlying mechanisms and the number of sessions needed to optimize this adaptive response remain unclear. We hypothesized that the responses to localized heating of the skin will be greater after 2 wk as opposed to 1 wk of RIPC. Furthermore, 2 wk of repeated RIPC will augment cutaneous VD responses to thermal and pharmacological stimuli. In methods, twenty-four participants (24 ± 2 yr; 13 men, 11 women) performed repeated RIPC (7 daily sessions over 1 wk, n = 11; 12 sessions over 2 wk, n = 13), consisting of four repetitions of 5 min of arm blood flow occlusion separated by 5 min reperfusion. Laser speckle contrast imaging was used to measure skin blood flow responses, in perfusion units (PU), to local heating (T loc  = 42°C), acetylcholine (ACh), and sodium nitroprusside (SNP) before and after repeated RIPC. Data were expressed as cutaneous vascular conductance (CVC, in PU/mmHg). In results, the VD response to local heating increased after RIPC (∆CVC from baseline; 1 wk: 0.94 ± 0.11 to 1.19 ± 0.15, 2 wk: 1.18 ± 0.07 to 1.33 ± 0.10 PU/mmHg; P < 0.05) but the ∆CVC did not differ between weeks. SNP-induced VD increased after 2 wk of RIPC (∆CVC; 0.34 ± 0.07 to 0.63 ± 0.11 PU/mmHg; P < 0.05), but ACh-induced VD did not. In conclusion, repeated RIPC improves local heating- and SNP-mediated cutaneous VD. When compared with 1 wk of RIPC, 2 wk of RIPC does not induce further improvements in cutaneous VD function. NEW & NOTEWORTHY Repeated RIPC increases the cutaneous vasodilatory response to local heating and to sodium nitroprusside but not to acetylcholine. Thus, endothelial-independent and local heating-mediated cutaneous vasodilation are improved following RIPC. However, 2 wk of RIPC sessions are not more effective than 1 wk of RIPC sessions in enhancing local heating-mediated cutaneous vasodilation.

A knowledgeable workforce is key to meeting the demands of an aging population that is expected to nearly triple by 2030 and their attitudes influence propensity to seek aging-related careers. Postsecondary education offers an opportunity to increase aging-related knowledge and facilitates intergenerational experiential-learning opportunities; however, research is lacking regarding attitudes toward aging and experiences among an academically diverse sample. To address this gap, the aims of this study were to (1) examine differences in students' attitudes toward older adults by academic college, (2) assess differences in aging-related coursework and course experiences by academic college, and (3) explore key factors associated with students' attitudes toward older adults. Online survey methodology was used with a sample of 816 undergraduate students from a single university who represented all academic colleges offering undergraduate degrees. Significant differences among students' attitudes toward older adults by academic college were noted: those enrolled in the College of Human Sciences reported better stereotype, separation, and affective attitudes. Furthermore, factors associated with students' aging-related attitudes were sex, affiliation with academic college, perception of "old," contact frequency, and desire to learn aging-related content. The authors suggest interdisciplinary and disciplinary-specific educational recommendations to improve students' attitudes toward older adults.

Key Points: Remote ischaemic preconditioning (RIPC), induced by brief bouts of ischaemia followed by reperfusion, confers vascular adaptations that protect against subsequent bouts of ischaemia; however, the effect of RIPC repeated over several days on the human microcirculation is unknown. Using skin as a model, microvascular function was assessed at a control and a NO-inhibited area of skin before 1 day after and 1 week after administering seven consecutive days of repeated RIPC on the contralateral arm. Maximal vasodilatation was increased by ∼20-50% following 7 days of repeated RIPC, and this response remained elevated 1 week after stopping RIPC; however, NO-mediated vasodilatation was not affected by the RIPC stimulus. These data indicate that repeated RIPC augments maximal vasodilatation, but the underlying mechanism for this improvement is largely independent of NO. This finding suggests a role for other endothelium-derived mediators and/or for endothelium-independent adaptations with repeated RIPC., Abstract: Remote ischaemic preconditioning (RIPC), induced by intermittent periods of ischaemia followed by reperfusion, confers cardiovascular protection from subsequent ischaemic bouts. RIPC increases conduit and resistance vessel function; however, the effect of RIPC on the microvasculature remains unclear. Using human skin as a microvascular model, we hypothesized that cutaneous vasodilatory (VD) function elicited by localized heating would be increased following repeated RIPC. Ten participants (23 ± 1 years, 6 males, 4 females) performed RIPC for seven consecutive days. Each daily RIPC session consisted of 4 repetitions of 5 min of arm blood flow occlusion interspersed by 5 min reperfusion. Before, 1 day after and 1 week after the 7 days of RIPC, two microdialysis fibres were placed in ventral forearm skin for continuous infusion of Ringer solution or 20 mM l-NAME. Red blood cell flux was measured by laser Doppler flowmetry at each fibre site during local heating (T loc  = 39°C) and during maximal VD elicited by heating (T loc  = 43°C) and 28 mM sodium nitroprusside infusion. Data were normalized to cutaneous vascular conductance (flux/mmHg). Seven days of RIPC did not alter the nitric oxide (NO) contribution to the VD response to local heating (P > 0.05). However, the maximal VD was augmented (Pre: 2.5 ± 0.2, Post: 3.8 ± 0.5 flux/mmHg; P < 0.05) and remained elevated 1 week post RIPC (3.3 ± 0.4 flux/mmHg; P < 0.05). Repeated RIPC improves maximal VD but does not affect NO-mediated VD in the cutaneous microvasculature. This finding suggests that other factors may explain the vasodilatory adaptations that occur following repeated RIPC., (© 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society.)

Although exercise has well-documented health benefits on cardiovascular disease (CVD), the benefit of combination exercise on CVD risk factors in individuals with elevated risk has not been fully elucidated. We compared the effects of aerobic, resistance, and a combination of both aerobic and resistance training on CVD risk factors including peripheral and central BP, cardiorespiratory fitness (CRF), muscular strength, body composition, blood glucose and lipids. Sixty-nine adults (58±7 years) with an elevated blood pressure or hypertension, overweight/obesity, and sedentary lifestyle were randomized to one of the three 8-week exercise programs or a non-exercise control group. Participants in all three exercise groups had an equal total exercise time, 3 days/week (aerobic: 60 minutes/session vs. resistance: 60 minutes/session vs. combination: aerobic 30 minutes/session plus resistance 30 minutes/session). Combined training provided significant reductions in peripheral (-4 mmHg) and central diastolic BP (-4 mmHg), increase in CRF (4.9 ml/kg/min), increase in upper (4 kg) and lower (11 kg) body strength, and increase in lean body mass (0.8 kg) (p <0.05). Aerobic training only increased CRF (7.7 ml/kg/min), and reduced body weight (-1.0 kg) and fat mass (-0.9 kg) (p <0.05). Resistance training only increased lower body strength (13 kg) and reduced waist circumference (-1.7 cm) (p <0.05). However, neither aerobic or resistance training alone showed significant reductions in BP (p>0.05). Furthermore, a composite score of CVD risk factors indicated a greater reduction with combination training compared to the control group. In conclusion, among individuals at an increased risk for CVD, as little as 8-weeks of combined training may provide more comprehensive CVD benefits compared to time-matched aerobic or resistance training alone., Competing Interests: The authors have declared that no competing interests exist.

Background: In young adults, blood flow restricted exercise (BFRE) at relatively low intensities can increase muscle strength as effectively as conventional high intensity training. Ischemic exercise can also increase collateral blood flow in skeletal muscle. However, the effects of chronic BFRE on muscle strength and blood flow in older adults remain unknown. The purpose of this study was to compare the effects of 4weeks of BFRE training on skeletal muscle strength and blood flow between young and older subjects and between older adults performing BFRE and conventional high intensity resistance exercise., Methods: Maximum voluntary contraction (MVC), forearm girth, peak forearm blood flow (FBF) and forearm vascular conductance (FVC) were assessed before and after 4weeks of forearm resistance training with BFRE in older adults (O-BFRE, 63±1 y, n=9) and younger adults (Y-BFRE, 22±1 y, n=8) and with high intensity training at 75% maximum voluntary contraction in older adults (O-HI, 63±1 y, n=10)., Results: MVC increased in all groups (O-BFRE, 33.4±4.7 to 36.3±4.7kg; Y-BFRE, 37.2±4.9 to 43.0±5.0kg; O-HI, 34.0±4.4 to 39.8±4.4kg; all p<0.05). Forearm girth increased in O-BFRE (26.3±1.1 to 26.7±1.1cm; p<0.05) and Y-BFRE (23.9±0.9 to 25.1±1.5cm; p<0.05) but not in O-HI (25.9±1.0 to 26.1±1.0cm; p=0.26). Peak forearm vascular conductance increased in Y-BFRE (0.190±0.016 to 0.311±0.031units; p=0.01) but not in O-BFRE (0.157±0.024 to 0.193±0.029units; p=0.48) and O-HI (0.188±0.035 to 0.227±0.035units; p=0.18)., Conclusion: These data suggest that chronic BFRE training is effective in increasing muscular strength, muscle size and vascularity in young adults but, in older adults, increases only muscular strength and size. Longer training durations or higher volumes may be required to evoke similar vascular adaptations in older adults., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Rural-residing older adults (OA) are not meeting physical activity (PA) recommendations, such that identifying methods of increasing PA among OA remains an ongoing challenge. This study evaluated the effect of a community-based exergaming program on PA readiness-to-change and self-efficacy among rural-residing OA (n = 265). There was a significant (p = .008) increase in readiness-to-change classification from PRE to POST. Significant increases in self-efficacy, or confidence in their ability to be physically active for a prescribed period of time, were detected for 35 (p = .011) and 40 min (p = .035) of continuous PA. PA self-efficacy change for 35 min of continuous PA (F [3,137] = 3.973, p = .010) and 40 min of continuous PA (F [3,137) = 2.893, p = .038) were influenced by the interaction between PRE self-reported health and PRE PA readiness-to-change levels. Results suggest that an exergaming-themed PA intervention is effective at increasing PA participation and self-efficacy for PA among rural-residing OA.

Background: The purpose of this study was to compare the effects of high and low velocity knee extension training on changes in muscle strength and mobility status in high-functioning older adults., Methods: Twenty-six (16 female, 10 male) older adults (mean age of 65) were randomized to either 6weeks of low velocity resistance training (LVRT) performed at 75°/s or high velocity resistance training (HVRT) performed at 240°/s. Both groups performed 3 sets of knee extension exercises at maximal effort, 3 times a week. Muscle strength was assessed through a range of testing velocities on an isokinetic dynamometer. Mobility status was assessed with the short physical performance battery (SPPB) and myosin heavy chain (MyHC) transcript levels were quantified via qRT-PCR., Results: From baseline to post-training, there were several significant (P<0.05) differences in muscle strength and functional characteristics in LVRT (n=13) and HVRT (n=13) groups. From baseline to post-training, MyHC-α mRNA and MyHC-IIa mRNA showed a significant (P<0.05) increase within HVRT but MyHC-IIx mRNA did not change significantly. Our results demonstrate HVRT provides a greater number of muscular enhancements when compared to LVRT, particularly under conditions of high velocity muscle contraction., Conclusion: HVRT is emerging as the optimal training stimulus for the older adult. The present study demonstrates, in addition to increased strength and functional outcomes, HVRT elicits a potentially therapeutic (i.e., slow to fast) transcriptional response in MyHC., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Many consumer-based physical activity monitors (PAMs) are available but it is not clear how to use them to most effectively promote weight loss. The purpose of this pilot study was to compare the effectiveness of a personal PAM, a guided weight loss program (GWL), and the combination of these approaches on weight loss and metabolic risk. Participants completed the study in two cohorts: Fall 2010 and Spring 2011. A sample of 72 obese individuals in the Ames, IA area were randomized to one of 3 conditions: 1) (GWL, N = 31), 2) PAM, N = 29, or 3) a combination group (PAM + GWL, N = 29). Weight and metabolic syndrome score (MetS), computed from waist circumference (WC), BMI, blood pressure (BP), and lipids were assessed at baseline and following an 8-week intervention. Weight was also assessed four months later. Two-way (Group × Time) ANOVAs examined intervention effects and maintenance. Effect sizes were used to compare magnitude of improvements among groups. During the intervention, all groups demonstrated significant improvements in weight and MetS (mean weight loss = 4.16 kg, p  < 0.001). Mean weight continued to decline modestly during follow-up, with average weight loss of 4.82 kg from baseline ( p  < 0.01). There were no group differences for weight loss but the PAM + GWL group had significantly larger changes in MetS score ( d  = 0.06-0.77). The use of PAM resulted in significant improvements in weight and MetS that were maintained across a four-month follow-up. Evidence suggests that the addition of GWL contributed to enhanced metabolic outcomes.

Introduction: This study evaluates whether a health club membership is associated with meeting the US physical activity (PA) guidelines and/or favorable cardiovascular health., Methods: Using cross-sectional data of health club members (n = 204) and non-members (n = 201) from April to August 2013, this is the first study to our knowledge to examine a health club membership in relation to objectively measured cardiovascular health indicators including resting blood pressure, resting heart rate, body mass index, waist circumference, and cardiorespiratory fitness based on a non-exercise test algorithm. To determine the total PA and sedentary time, this study used a comprehensive PA questionnaire about both aerobic and resistance activities at the health club, as well as lifestyle activities in other settings, which was developed based on the International Physical Activity Questionnaire (IPAQ)., Results: The odds ratios (95% confidence interval) of meeting either the aerobic, resistance, or both aerobic and resistance PA guidelines for members compared to non-members were 16.5 (9.8-27.6), 10.1 (6.2-16.3), and 13.8 (8.5-22.4), respectively. Significant associations of health club membership with more favorable cardiovascular health outcomes and sedentary behavior were observed for resting heart rate (B: -4.8 b/min, p<0.001), cardiorespiratory fitness (B: 2.1 ml/kg/min, p<0.001), and sedentary time (B: -1.4 hours, p<0.001). Participants with a health club membership of >1 year had more favorable health outcomes, with a smaller waist circumference (men, B: -4.0 cm, p = 0.04; women, B: -3.4 cm, p = 0.06), compared to non-members., Conclusions: Health club membership is associated with significantly increased aerobic and resistance physical activity levels and more favorable cardiovascular health outcomes compared to non-members. However, longitudinal, randomized controlled trials would be clearly warranted as cross-sectional data prohibits causal inferences., Competing Interests: The authors have declared that no competing interests exist.

Objective: The aim of this study was to examine the associations of physical activity and body mass index (BMI) with the metabolic syndrome (MetS) in police officers., Methods: Self-reported physical activity, MetS, and a modified MetS (MMetS, excluding obesity) were assessed in 448 officers., Results: Of the officers, 27.5% had MetS, 48.7% were overweight, and 31.7% were obese. Being overweight and obese increased the MetS risk by 6.8- and 10.9-fold, respectively, independent of physical activity level. Moderate and low levels of physical activity were associated with a 1.9- and 2.5-fold increased risk for MetS, but not after adjusting for BMI. However, within BMI categories, the risk for MMetS was lower as physical activity increased., Conclusion: In police, a higher BMI is more critical than reduced physical activity for MetS risk; however, physical activity can attenuate some of the risk associated with a higher BMI.

Objectives: The aim of the study was to determine whether sleep quality is associated with an increased risk for cardiovascular disease (CVD) or worsened mental health., Methods: Self-reported sleep quality, 35 inflammatory factors, CVD risk factors, personal stress, police operational and organizational stress, social support, depressive symptoms, and health-related quality of life were compared among a cohort of officers., Results: Of 379 officers, 39% and 27% had poor and borderline sleep quality. Sleep quality was not associated with either an altered inflammatory profile or worsened CVD risk factors. Compared with good sleepers, borderline and poor sleepers reported increased personal stress, police organizational and operational stress, and depressive symptoms, but decreased health-related quality of life., Conclusions: Poor sleep quality is prevalent in the law enforcement profession and is associated with worsened mental health but not with an increased risk for CVD.

Objective: The aim of this study is to examine a resilience training intervention that impacts autonomic responses to stress and improves cardiovascular risk, psychological, and physiological outcomes in police., Methods: Officers [(n = 38) 22 to 54 years] modified emotional and physical responses to stress using self-regulation. Measurements include psychological and physiological measures [eg, heart rate variability (HRV), blood pressure, C-reactive protein)] obtained at three time intervals., Results: Age was significantly (P < 0.05) associated with changes on several measures of psychological stress (eg, critical incident stress, emotional vitality, and depression). Associations were found between coherence and improved HbA1c (r = -0.66, P < 0.001) and stress due to organizational pressures (r = -0.44, P = 0.03). Improvements in sympathetic and parasympathetic contributors of HRV were significant (P < 0.03)., Conclusion: A stress-resilience intervention improves certain responses to job stress with greater benefits for younger participants.

Despite a growing older adult population, Iowa Congregate Meal Program (CMP) participation has declined. Motivators and barriers to congregate mealsite participation and wellness programming preferences of baby boomers and older adults were examined to provide insight to how to revise and better promote the CMP for the next generation of older adults. Four focus group sessions were conducted with 27 primarily White, rural-residing adults, ages 48-88 years. Participation motivators included educational programs, food, and socialization while barriers included negative perceptions and stereotypes associated with congregate mealsites. Desired wellness programs were viewed as interactive and relevant. Healthcare was the leading wellness need with financial management and physical activity cited as the most-wanted topics of wellness programs. These results provide insight on factors, aside from funding, that may be adversely impacting CMP participation and identifies areas for further investigation.

Background/objectives: Objective and subjective measurement instruments have been used to estimate energy expenditure (EE) as alternatives to the doubly labeled water (DLW) methodology, but their relative validity for older adults remains uncertain. The purpose of this study was to validate an objective monitor (SenseWear Mini Armband) and a self-report instrument (7-Day Physical Activity Recall, 7D-PAR) relative to the DLW under free-living conditions in older adults., Subjects/methods: Twenty-nine older adults (60-78 years) each wore the Mini for 14 consecutive days and completed two 7D-PARs after each week. For each measurement method, activity EE (AEE) was calculated as total EE (TEE)—measured resting metabolic rate (RMR)—diet induced thermogenesis (10% of TEE). TEE and AEE from the Mini and 7D-PAR were each compared with values from the DLW., Results: Equivalence testing indicated that estimates of TEE from the Mini and the 7D-PAR were statistically equivalent to those measured with DLW; however, differences were evident for estimates of AEE. The Mini had smaller mean absolute percent error for TEE (8.0%) and AEE (28.4%) compared with the 7D-PAR (13.8 and 84.5%, respectively) and less systematic bias in the estimates., Conclusions: The Mini and 7D-PAR provided reasonably valid estimates of TEE but large errors in estimating AEE. The Mini and 7D-PAR have the potential to accurately estimate TEE for older adults.

Exergaming may be an effective strategy to increase physical activity participation among rural older adults. This pilot project examined the effects of a 24-wk exergaming and wellness program (8 wk onsite exergaming, 16-wk wellness newsletter intervention) on physical activity participation and subjective health in 46 rural older adults. Sociodemographic data and self-reported physical activity were analyzed using descriptive statistics and Cochran's Q, respectively. Qualitative data were reviewed, categorized on the basis of theme, and tabulated for frequency. Increased physical activity and perceived health were the most reported perceived positive changes. Significant increases in physical activity participation were maintained among participants who were physically inactive at baseline. Best-liked features were physical activity and socialization. Findings suggest that this pilot exergaming and wellness program is effective in increasing physical activity in sedentary rural older adults, increasing socialization, and increasing subjective physical health among rural older adults.

Objective: Police officers have a higher risk for cardiovascular disease. Reductions in occupational physical activity may contribute to the risk, yet there have been few efforts to characterize the physical demands of police work beyond self-report., Purpose: To compare measured physical activity between work and off-duty hours and assess the effects of stress on physical activity., Methods: Officers (n = 119) from six departments wore a pattern recognition monitor for 96 hours to measure total energy expenditure (kilocalorie per hour) (1k/cal = 4184 joules), activity intensity, and step count per hour., Results: Participants were more active on their off-duty days than at work; the effects of stress on physical activity seemed moderated by sex., Conclusions: Police work is primarily a sedentary occupation, and officers tend to be more active on their off-duty days than during their work hours.

Objective: To assess the association of sleep characteristics and mental health with the metabolic syndrome (MetS) in law enforcement officers (LEOs)., Methods: Sleep duration (≤6, >6-<8, ≥8 hours/night), sleep quality ("good," "poor"), mental health (stress, burnout, depression), and MetS components were compared in 106 LEOs., Results: The prevalence of MetS was 33%. After covariate adjustment including the mental health measures, long sleep duration was associated with MetS (odds ratio = 4.89, 95% confidence interval = 1.32 to 18.13), whereas sleep quality was not. LEOs with short sleep duration or poor sleep quality reported more stress, burnout, and depression symptoms., Conclusions: In LEOs, sleep duration is more strongly associated with the occurrence of MetS than sleep quality, independent of mental health. Nevertheless, short sleep duration and poor sleep quality may affect mental health in LEOs.

A 6-wk group balance-training program was conducted with physically active older adults (based on American College of Sports Medicine requirements) to investigate the effect of dose-related static and dynamic balance-specific training. All participants, age 60-87 yr, continued their regular exercise program while adding balance training in 1 of 3 doses: three 20-min sessions/wk (n = 20), one 20-min session/wk (n = 21), or no balance training (n = 19). Static balance (single-leg-stance, tandem), dynamic balance (alternate stepping, limits of stability), and balance confidence (ABC) were assessed pre- and posttraining. Significant interactions were observed for time in single-leg stance, excursion in limits of stability, and balance confidence, with the greatest increase observed in the group that completed 3 training sessions/wk. The results demonstrate a dose-response relationship indicating that those who are already physically active can improve balance performance with the addition of balance-specific training.

This study assessed the association between perceived health, fatigue, positive and negative affect, handgrip strength, objectively measured physical activity, body mass index, and self-reported functional limitations, assessed 6 months later, among 11 centenarians (age = 102 +/- 1). Activities of daily living, assessed 6 months prior to assessment of functional limitations, were also included in the model. Handgrip strength, positive affect, and self-rated current health were associated with higher functioning, expressed as either global, upper body, or lower body functioning (r > .60). Objectively measured physical activity was inversely related to the aforementioned measures of functioning. Thus, physical health as assessed by handgrip strength, but not by physical activity, is associated with better functioning in centenarians.

Law enforcement officers suffer higher morbidity and mortality rates from all causes than the general population. Cardiovascular disease (CVD) accounts for a significant portion of the excess illness, with a reported prevalence as high as 1.7 times that of the general population. To determine which occupational hazards cause this increased risk and morbidity, it is imperative to study law enforcement officers before they retire. The long-range goal of our research is to reduce the incidence of CVD-related illness and death among aging law enforcement officers. The purpose of the present study was to measure pro- and anti-atherogenic inflammatory markers in blood samples from law enforcement officers (n = 71) and determine what types of occupation-related stress correlate with differences in these markers. For each outcome variable of interest, we developed separate regression models. Two groups of potential predictors were examined for inclusion in the models. Selected measures of stress were examined for inclusion in the models, in addition to general covariates, such as gender, ethnicity, years in law enforcement, and body mass index. Our results revealed statistically significant relationships between several physiologic variables and measures of stress.

Purpose: To assess the levels of stress and the prevalence of cardiovascular disease (CVD) risk factors in female law enforcement officers (LEOs)., Methods: Self-reported data including job-related stress and CVD risk factors were obtained from 65 female LEOs. Stress scores were compared with 429 males LEOs and CVD risk factors were compared with 1,213 demographically similar female respondents to the CDC BRFSS survey. All subjects resided in Iowa., Results: Female LEOs had more stress (perceived stress, p < 0.01), more job-related stress (job strain, vital exhaustion and effort-reward imbalance, p < 0.01 for all), but similar social support (social provision scale, p = 0.412) than male LEOs. Female LEOs had a significantly higher prevalence of hypercholesterolemia than the general Iowa female population (46.2 vs. 29.3%, p < 0.01). There was a trend towards a higher prevalence of diabetes in female LEOs (9.2 vs. 4.5%, p = 0.084). The most commonly cited contributor to their perceived CVD risk was stress (77%). Female LEOs who felt that being either a LEO (67.7%) or a female LEO (41.5%) contributed to their risk for chronic diseases had more stress and a higher prevalence of overweight and obesity than female LEOs who felt differently., Conclusions: Female LEOs have higher stress than male LEOs. The prevalences of hypercholesterolemia and diabetes are higher in female LEOs than that of the general female population. Thus, female LEOs may be at a greater risk for CVD than their male counterparts.

Objective: To determine whether job-related stress is associated with alterations in pro- and anti-atherogenic inflammatory mediators among law enforcement officers., Methods: Markers of vascular inflammation and the self-reported stress measures of perceived stress, vital exhaustion, job strain, effort-reward imbalance, and social support were compared between officers (N = 444) and non-officers (N = 166)., Results: Officers had higher levels of IL-1beta, IL-6, IL-10, and TNF-alpha and lower levels of C-reactive protein and fibrinogen. No more than 4% of the variability in any of the inflammatory mediators was explained by any stress measure for either the two groups or the entire sample., Conclusions: Law enforcement officers may be at an increased risk for cardiovascular disease due to a relatively greater pro-inflammatory vascular environment. However, this increased risk cannot be attributed to either chronic stress or the work-related stress measures assessed here.

Unlabelled: It would be useful to be able to predict tolerance to lower body negative pressure (LBNP) because of the association of low LBNP tolerance to low orthostatic tolerance., Purpose: To determine how well tolerance to LBNP can be modeled using laboratory variables assessed noninvasively., Methods: There were 125 male and female college age and older (> 60 yr) subjects who underwent graded LBNP to presyncope. Tolerance was quantified by the LBNP tolerance index (LTI). Noninvasive variables assessed at rest and at presyncope were used to predict LTI via structural equation modeling (SEM). SEM can better address the correlation and variable interaction effects inherent in assessing orthostatic tolerance, e.g., multicollinearity, compared to traditional regression techniques., Results: With SEM, the manifest variables of gender, % body fat, maximal change in heart rate from rest to presyncope (delta HR), and resting total peripheral conductance (TPC) explained 40% of the variance in LTI. All the variables had direct significant influences on LTI; in addition, % body fat mediated the influence of gender and age while AHR mediated the effects of TPC. An exaggerated HR response to LBNP was associated with an increased LBNP tolerance (beta = -0.396)., Conclusion: About 40% of the variability in LBNP tolerance can be predicted using easily measured variables. Male gender, a potentiated HR response to LBNP, higher resting TPC, older age, and lower body fat are associated with an increased LBNP tolerance.

Objective: To assess the prevalence of cardiovascular disease (CVD) risk factors and frequency of risk screening in volunteer firefighters., Methods: Self-reported data were obtained from 230 volunteer firefighters., Results: Most participants were either overweight (35%) or obese (41%) and did not know either their blood lipid (86%) or blood pressure (47%) values. Only 35% reported having had a blood lipid assessment in the past year, whereas 39% had never done so; 93% had had their blood pressure assessed in the past year and only 2% had never done so. Thirty percent reported currently using tobacco., Conclusions: The prevalence of overweight, obesity, and tobacco use among these volunteer firefighters was higher than that found in the general population. Many firefighters were either not aware of their risk factors for CVD or had been inadequately screened for this risk. However, the firefighters who had had recent blood pressure and lipid assessments did not have markedly elevated values. Thus, CVD risk in volunteer firefighters may be reduced through an increased awareness of risk factors via timely risk factor assessment.

Objective: : To examine the independent and combined interrelationships among physical activity, perceived stress, and the metabolic syndrome in law enforcement officers (LEOs)., Methods: : Perceived stress, self-reported physical activity, and metabolic syndrome risk factors were assessed in 386 white male LEOs., Results: : Among the LEOs, 23.1% had the metabolic syndrome. The metabolic syndrome was not significantly associated with perceived stress (r = 0.047) whereas physical activity was (r = -0.225, P < 0.0001). The odds ratios (95% CI) for possessing the metabolic syndrome in the low and moderate physical activity groups compared to the high physical activity group were 3.13 (95% CI = 1.56 to 6.26) and 2.30 (95% CI = 1.29 to 4.09), respectively., Conclusions: : Regardless of stress level, physical inactivity is an important risk factor in the metabolic syndrome among this unique occupational group.

The 6-min walk test (6MWT) is a common component of fitness assessments of older adults; however, differing course configurations might affect 6MWT performance. It is unclear how comparable 2 different configurations are. To determine the comparability of 2 courses, 35 adults >65 years of age completed two 6MWT, once walking around a 20- by 5-yd outdoor rectangle and once on an indoor oval track (circumference 144.3 yd). Scores for the 2 tests were internally consistent (intraclass correlation coefficient = .95). The participants walked farther on the oval track than around the rectangle (639 +/- 19 vs. 582 +/- 16 yd; p < .0001), but responses to the rectangular configuration could be readily estimated using the equation 66.7 yd + 0.807 x (oval walking distance), R2 = .85. Thus, within-participant responses are similar across both 6MWT, but the course configuration affects the distance walked.

Increased serum levels of inflammatory mediators have been associated with numerous disease states including atherosclerosis, Type II diabetes, hypertension, depression, and overall mortality. We hypothesized that a long-term exercise intervention among older adults would reduce serum inflammatory cytokines, and this reduction would be mediated, in part, by improvements in psychosocial factors and/or by beta-adrenergic receptor mechanisms. Adults age 64 were randomly assigned to either an aerobic exercise treatment (CARDIO) or a flexibility/strength exercise treatment (FLEX) 3 days/week, 45 min/day for 10 months. A subgroup of subjects treated with non-selective beta(1)beta(2) adrenergic antagonists were included to evaluate the potential role of beta-adrenergic receptor adaptations as mediators of an exercise-induced change in inflammation. The inflammatory mediators [C-reactive protein (CRP), IL-6, tumor necrosis factor (TNF)-alpha, and IL-18] and the psychosocial factors (depression, perceived stress, optimism, sense of coherence, and social support) were measured pre- and post-intervention. The CARDIO treatment resulted in significant reductions in serum CRP, IL-6, and IL-18 compared to the FLEX treatment (significant treatment x time interaction, p<.05), whereas TNFalpha declined in both groups (main effect of time, p=.001). However, several psychosocial factors (depression, optimism, and sense of coherence) improved in both groups suggesting that the reduction of CRP, IL-6, and IL-18 in the CARDIO group was not mediated by improvements in psychosocial scores. With respect to the potential role of beta-adrenergic receptors, both CARDIO subjects treated with beta-adrenergic antagonists and those who were not treated with those medications demonstrated similar reductions in serum CRP, IL-6, IL-18, and TNFalpha. In summary, we have observed that an aerobic exercise intervention can significantly reduce serum inflammatory mediators, but beta-adrenergic receptors and psychosocial factors do not appear to be involved.

Background: Animal models suggest that aging negatively affects the cerebral blood flow (CBF) response to a hypotensive challenge while research with humans suggests that chronic physical activity may positively affect age-associated alterations in CBF. The extent to which chronic exercise affects the CBF responses to orthostatic stress in older subjects is unknown., Objectives: The purpose of this study was to determine the extent to which differences in age and cardiovascular fitness, reflective of differences in chronic exercise training, affect cerebral blood flow responses to severe orthostatic stress., Methods: Subjects were divided into four groups: old fit (OF; 72 +/- 2 year-olds; 38.7 +/- 1.6 ml.kg(-1).min(-1)), old unfit (OU; 71 +/- 1 year-olds; 27.7 +/- 2.9 ml.kg(-1).min(-1)), young fit (YF; 23 +/- 0.5 year-olds; 56.1 +/- 1.8 ml.kg(-1).min(-1)) and young unfit (YU; 23 +/- 1 year-olds; 41.1 +/- 1.6 ml.kg(-1).min(-1)). Fitness was quantified with maximal graded exercise testing. Middle cerebral artery blood flow velocity (CBF velocity; transcranial Doppler) responses to graded orthostatic stress (lower body negative pressure) to presyncope were assessed., Results: Orthostatic tolerance did not differ between groups (p = 0.633). The groups differed in fitness (YF >YU = OF >OU; p < 0.001) but not in either resting CBF velocity (p = 0.364) or pulsatility index (PI; p = 0.251). CBF velocity decreased below rest in the last completed stage of submaximal LBNP (p < 0.001) but did not differ between groups (p = 0.182). PI did not change with submaximal LBNP within groups. At presyncope, mean CBF velocity decreased below that of the last completed stage of LBNP in all groups (p < 0.001) while the PI increased in the young fit group only (p < 0.001)., Conclusion: Marked differences in age and fitness did not affect cerebral blood flow responses to severe orthostatic stress. While severe orthostatic stress can compromise CBF velocity in all age groups, older adults appear to autoregulate CBF as well as much younger subjects.

Aging and chronic exercise training influence leg venous compliance. Venous compliance affects responses to an orthostatic stress. The extent to which exercise training in a previously sedentary older population will affect venous compliance and tolerance to the simulated orthostatic stress of maximal lower body negative pressure (LBNP) is unknown. The purpose of this investigation is to determine the influence of a 6-mo endurance-training program on calf venous compliance and responses and tolerance to maximal LBNP in older men and women. Twenty participants (exercise group: n = 10, 5 men, 5 women; control group: n = 10, 6 men, 4 women; all >60 yr) underwent graded LBNP to presyncope or 4 min at -100 mmHg before and after a 6-mo endurance-training program. Utilizing venous occlusion plethysmography, calf venous compliance was determined in both groups using the first derivative of the pressure-volume relation during cuff pressure reduction before training, at 3 mo, and at the end of the training program. The exercise group improved their fitness with the 6-mo endurance-training program, whereas the control group did not change (14 +/- 3 vs. <1 +/- 2%; P < 0.05). LBNP tolerance did not differ between groups or across trials (P = 0.47). Venous compliance was not different between groups or trials, either initially or after 3 mo of endurance training, but tended to be greater in the exercise group after 6 mo of training (P = 0.08). These data suggest that a 6-mo endurance-training program may improve venous compliance without affecting tolerance to maximal LBNP in older participants.

Background: The purpose of this investigation was to determine the effects of age and fitness on tolerance to maximal lower body negative pressure (LBNP)., Methods: Ten older fit (OF) [73.9 +/- 2 years; 39.0 +/- 2 ml.kg(-1).min(-1) (age and estimated VO(2)peak, respectively)], 10 older unfit (OU) (70.9 +/- 1 years; 27.1 +/- 2 ml.kg(-1).min(-1)), 10 young fit (YF) (22.6 +/- 0.5 years; 57.1 +/- 2 ml.kg(-1).min(-1)), and 10 young unfit (YU) (23.1 +/- 1 years; 41.1 +/- 2 ml.kg(-1).min(-1)) participants underwent graded LBNP of -10 mmHg every 4 minutes to either presyncope or -100 mmHg., Results: Compared to the other groups, YF had an earlier increase in heart rate (-40 mmHg vs the last stage; YF vs OF, OU, and YU, respectively) and decline in stroke volume (-20 mmHg vs -40 mmHg; YF vs OF, OU, and YU, respectively). OU had a higher resting mean arterial pressure; this difference was maintained until the last stage. OF had an earlier decline in total peripheral conductance than the other groups (-20 mmHg vs -40 mmHg). Tolerance to maximal LBNP did not differ among the groups., Conclusions: Despite differences in the responses to submaximal LBNP, neither age nor cardiovascular fitness affect tolerance to maximal LBNP.

Aging and chronic exercise training influence leg venous compliance. Venous compliance affects responses to an orthostatic stress; its effect on tolerance to maximal lower body negative pressure (LBNP) in the elderly is unknown. The purpose of this study was to determine the influence of age and fitness, a surrogate measure of exercise training, on calf venous compliance and tolerance to maximal LBNP in men and women. Forty participants, 10 young fit (YF; age = 22.6 +/- 0.5 yr, peak oxygen uptake = 57.1 +/- 2.0 ml.kg(-1).min(-1)), 10 young unfit (YU; 23.1 +/- 1.0 yr, 41.1 +/- 2.0 ml.kg(-1).min(-1)), 10 older fit (OF; 73.9 +/- 2.0 yr, 39.0 +/- 2.0 ml.kg(-1).min(-1)), and 10 older unfit (OU; 70.9 +/- 1.6 yr, 27.1 +/- 2.0 ml.kg(-1).min(-1)), underwent graded LBNP to presyncope or 4 min at -100 mmHg. By utilizing venous occlusion plethysmography, calf venous compliance was determined by using the first derivative of the pressure-volume relation during cuff pressure reduction. We found that the more fit groups had greater venous compliance than their unfit peers (P < 0.05) as did the young groups compared with their older peers (P < 0.05) such that OU < YU = OF < YF. LBNP tolerance did not differ between groups. In conclusion, these data suggest that aging reduces, and chronic exercise increases, venous compliance. However, these data do not support a significant influence of venous compliance on LBNP tolerance.

The reproducibility of heart rate variability (HRV) measures during graded lower body negative pressure (LBNP) have not been studied in sufficient detail. Active college age men (n=14) underwent an orientation exposure and two trials of graded LBNP to presyncope or -100 mmHg, separated by 1 week. Heart rate, stroke volume (impedance cardiography), blood pressure (Finapres), and forearm blood flow were assessed, as was HRV in both time and frequency domains. The trial-to-trial responses to LBNP common to all subjects (LBNP< or =-60 mmHg and at test termination) showed parallel changes, suggesting similar responses between both trials. Good reproducibility estimates were found for the resting HRV data (lowest: R=0.62 for low frequency/high frequency ratio; highest: R=0.94 for standard deviation of normal R-R intervals). During LBNP, reproducibility estimates varied but were generally similar to that seen at rest. At test termination, they were unacceptably low (R<0.41) for the HRV data assessed in the frequency domain and expressed in absolute units. LBNP tolerance was lower in the first trial [LBNP tolerance index: 404 (21) versus 437 (15) mmHg min(-1); P<0.05] but the intraclass correlation coefficient was high (R=0.87). These data suggest that (1) HRV responses to submaximal LBNP up to -60 mmHg are consistent across trials, (2) the considerable variability seen in the HRV parameters at maximal LBNP can be reduced by expressing these data in either the time domain or using normalized units in the frequency domain, and (3) cardiovascular responses to sub- and maximal LBNP are reproducible. Data are presented as mean (SEM) unless otherwise stated.

This study tested the hypothesis that normotensive black males differ from white males in their autonomic and cardiovascular responses to severe orthostatic stress. College age men (9 blacks, 9 whites) underwent graded lower body negative pressure (LBNP; 10 mmHg steps of 6 min each) to either -100 mmHg or presyncope. LBNP tolerance between the two groups did not differ (LBNP tolerance index: 378 +/- 34 vs 404 +/- 1 9mmHg.min, blacks vs whites). Responses to LBNP common to all subjects (< or = -40 mmHg), including spontaneous baroreflex sensitivity (sequence technique), did not differ between groups except whites experienced an earlier and more pronounced decline in total peripheral conductance than blacks (P < 0.01). At test termination, the heart rate variability measure of low frequency/high frequency ratio increased more in blacks than whites (5.2 +/- 1.1 vs 2.7 +/- 0.7 units; P < 0.05) while cardiac output and total peripheral conductance were lower in whites (both P < 0.05). These data suggest that blacks and whites have similar LBNP tolerances. They maintain blood pressure equally well when exposed to graded LBNP to presyncope, yet they differ in their mechanisms for doing so.

The bioavailability of soybean isoflavones varies widely among individuals due to many factors, including activities of gut microflora. To characterize factors that affect fecal isoflavone disappearance phenotype and isoflavone bioavailability in women, 35 Asian and 33 Caucasian women, 18-43 y of age, provided fecal samples for anaerobic incubation with isoflavones in vitro at two times 5 mo apart (Phases I and II). Diet, physical activity and health history were investigated at these times. A single dose of soymilk powder [1.2 mg (4.57 micromol) total isoflavone/kg body] was given to all subjects with breakfast in phase II. Daidzein and genistein from fecal incubations, urine and fecal samples were measured by reverse-phase HPLC. Three significantly different daidzein and two genistein disappearance phenotypes were identified from fecal isoflavone incubations. More Asians than Caucasians were identified within the high daidzein disappearance phenotype. Caucasians and Asians differed significantly in daily intake of red meat (0.3 +/- 0.1 vs. 1.0 +/- 0.1 servings/d), dairy foods (2.9 +/- 0.2 vs. 1.2 +/- 0.2 servings/d) and insoluble dietary fiber (3.6 +/- 0.3 vs. 1.4 +/- 0.3 g). BMI, maximal oxygen uptake (VO(2 max)) and physical activity level were significantly greater in Caucasians than in Asians. Asian subjects of the low genistein disappearance phenotype had more rapid gut transit time (GTT) and greater isoflavone bioavailability as reflected in urinary genistein excretion than did Asians of the high genistein disappearance phenotype (GTT, 40 +/- 8 vs. 63 +/- 5 h; 11.0 +/- 2.7 vs. 4.0 +/- 1.7% of ingested genistein excreted in urine). Caucasians of both genistein disappearance phenotypes had longer GTT than did Asian subjects (84 +/- 5 vs. 56 +/- 6 h) and resembled Asians of the high genistein disappearance phenotype in genistein bioavailability. Relatively rapid GTT coupled with a low fecal isoflavone disappearance phenotype as occurred in Asian but not Caucasian subjects produced greater genistein bioavailability, as reflected in urinary genistein excretion.

Background: This study investigated the hypothesis that expressions of maximal and submaximal bilateral indices would not differ between older and young participants., Methods: Twenty older (73.3 +/- 4.4 years) and 21 younger (22.4 +/- 0.9 years) participants performed maximal voluntary isometric contractions of the elbow flexor muscles, using the right arm only, left arm only, and both arms simultaneously. The participants were asked to repeat these contractions at what they perceived to be 25%, 50%, and 75% of their maximal voluntary isometric contraction levels., Results: Significant bilateral deficits (p <.05), defined as a bilateral index <0, existed at maximal and submaximal intensities, but the submaximal deficits (14-18%) were larger than the maximal deficits (11%). Normalized integrated electromyographic values tended to be higher for unilateral trials than for bilateral trials at all submaximal intensity levels. There were no significant differences between the older and young participants., Conclusions: Despite the decrease in the size of fast twitch motor units associated with aging, bilateral deficits exist in older adults, do not differ from those observed for younger adults, and remain larger for submaximal intensities.

This study tested the hypotheses that trained swimmers would have greater orthostatic tolerance than runners and, if present, it would be due to differences in their autonomic and hemodynamic responses to graded central hypovolemia. Twenty intercollegiate male athletes [11 runners and 9 swimmers; .VO(2max) =70.0 (1.6) vs 69.5 (2.6) ml.kg(-1).min(-1), respectively] underwent graded lower body negative pressure (LBNP) to presyncope. The swimmers were heavier [80.5 (1.9) vs 70.3 (1.9) kg, P<0.05], with larger resting cardiac [4.44 (0.29) vs 3.68 (0.18) l.min(-1).m(-2)] and total peripheral conductance [0.056 (0.04) vs 0.044 (0.02) units.m(-2)] indices. Neither spontaneous cardiac baroreflex sensitivity (sequence method) nor heart rate variability (spectral analysis) differed significantly between groups at rest. LBNP tolerance did not differ between groups, with an index value of 51 (2) kPa.min for the runners and 54 (4) kPa.min for the swimmers [383 (16) vs 402 (32) mmHg.min], although the swimmers had larger declines in pulse pressure and tended ( P=0.078) to have larger declines in total peripheral conductance index in the last completed stage of LBNP. These responses did not differ between groups in the last 2 min of LBNP. Neither the heart rate, mean arterial pressure nor forearm vascular conductance responses differed between groups throughout. Changes in heart rate variability indices did not differ significantly between groups, with similar declines in the high frequency component and increases in the low frequency/high frequency ratio. These data suggest that swim training does not lead to greater orthostatic tolerance than run training, and responses to maximal LBNP do not differ between swimmers and runners. Moreover, neither heart rate nor the autonomic modulation of the heart rate response to LBNP are affected by training modality.

This study tested the hypotheses that differences in the adrenergic, central venous pressure (CVP), cardiovascular, or baroreflex responses to lower body negative pressure (LBNP) or differences in body size would be associated with gender differences in orthostatic tolerance. Subjects (24 females, 22 males) underwent graded LBNP to -100 mmHg or presyncope. At rest, the males had higher SV (+ 21 ml x beat(-1)), cardiac output (+ 1.65 L x min(-1)), systolic blood pressure (+ 29 mmHg) and mean arterial pressure (+ 8 mmHg; all P < 0.05). Neither the CVP responses to LBNP to -60 mmHg, the deltaforearm vascular conductance/deltaCVP with LBNP to -20 mmHg nor the deltaheart rate/deltaCVP with LBNP of -30 to -60 mmHg differed between genders. LBNP tolerance was lower for the females than males (276 +/- 12 vs 337 +/- 14 mmHg x min; LBNP tolerance index; P < 0.01) and, of the resting data, only gender was associated with LBNP tolerance (R(2) = 20 %). Use of gender, the maximal change in HR with LBNP and the change in HR from 0 to -40 mmHg in a regression equation could explain 75 % of the variability in orthostatic tolerance. No cardiovascular parameter differed between genders in the two minutes preceding presyncope. In the last completed stage and at test termination, [epinephrine] and [norepinephrine] were higher in the men. These data suggest that the CVP, cardiovascular and baroreflex responses to graded LBNP are similar in men and women despite marked differences in LBNP tolerance. Differences in body size do not explain the gender difference although differences in the adrenergic responses at maximal LBNP may play a role.

Objective: The effectiveness of an androgenic nutritional supplement designed to enhance serum testosterone concentrations and prevent the formation of dihydrotestosterone and estrogen was investigated in healthy 3 to 58 year old men., Design: Subjects were randomly assigned to consume a nutritional supplement (AND-HB) containing 300-mg androstenediol, 480-mg saw palmetto, 450-mg indole-3-carbinol, 300-mg chrysin, 1,500 mg gamma-linolenic acid and 1.350-mg Tribulus terrestris per day (n = 28), or placebo (n = 27) for 28 days. Subjects were stratified into age groups to represent the fourth (30 year olds, n = 20), fifth (40 year olds, n = 20) and sixth (50 year olds, n = 16) decades of life., Measurements: Serum free testosterone, total testosterone, androstenedione, dihydrotestosterone, estradiol, prostate specific antigen and lipid concentrations were measured before supplementation and weekly for four weeks., Results: Basal serum total testosterone, estradiol, and prostate specific antigen (PSA) concentrations were not different between age groups. Basal serum free testosterone concentrations were higher (p < 0.05) in the 30- (70.5 +/- 3.6 pmol/L) than in the 50 year olds (50.8 +/- 4.5 pmol/L). Basal serum androstenedione and dihydrotestosterone (DHT) concentrations were significantly higher in the 30- (for androstenedione and DHT, respectively, 10.4 +/- 0.6 nmol/L and 2198.2 +/- 166.5 pmol/L) than in the 40- (6.8 +/- 0.5 nmol/L and 1736.8 +/- 152.0 pmol/L) or 50 year olds (6.0 +/- 0.7 nmol/L and 1983.7 +/- 147.8 pmol/L). Basal serum hormone concentrations did not differ between the treatment groups. Serum concentrations of total testosterone and PSA were unchanged by supplementation. Ingestion of AND-HB resulted in increased (p < 0.05) serum androstenedione (174%), free testosterone (37%), DHT (57%) and estradiol (86%) throughout the four weeks. There was no relationship between the increases in serum free testosterone, androstenedione, DHT, or estradiol and age (r2 = 0.08, 0.03, 0.05 and 0.02, respectively). Serum HDL-C concentrations were reduced (p < 0.05) by 0.14 mmol/L in AND-HB., Conclusions: These data indicate that ingestion of androstenediol combined with herbal products does not prevent the formation of estradiol and dihydrotestosterone.