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Purpose: This meta-analysis aimed to (1) provide a comparison of peak changes in indirect markers of exercise-induced muscle damage (EIMD) in youths versus adults and (2) determine if the involved limb moderated this effect., Method: Studies were eligible for inclusion if they (1) provided a human youth versus adult comparison; (2) provided data on muscle strength, soreness, or creatine kinase markers beyond ≥24 hours; and (3) did not provide a recovery treatment. Effect sizes (ES) were presented alongside 95% confidence intervals., Results: EIMD exhibited larger effects on adults than in youths for muscle strength (ES = -2.01; P < .001), muscle soreness (ES = -1.52; P < .001), and creatine kinase (ES = -1.98; P < .001). The random effects meta-regression indicated that the effects of upper- and lower-limb exercise in youths and adults were significant for muscle soreness (coefficient estimate = 1.11; P < .001) but not for muscle strength or creatine kinase (P > .05). As such, the between-group effects for muscle soreness (ES = -2.10 vs -1.03; P < .05) were greater in the upper than lower limbs., Conclusion: The magnitude of EIMD in youths is substantially less than in their adult counterparts, and this effect is greater in upper than lower limbs for muscle soreness. These findings help guide practitioners who may be concerned about the potential impact of EIMD when training youth athletes.

Background: Ageing is accompanied by decreases in physical capacity and physiological regulatory mechanisms including altered hormonal regulation compared with age-matched sedentary people. The potential benefits of exercise in restoring such altered hormone production and secretion compared to age-matched physically inactive individuals who are ageing remains unclear., Objectives: The aim of this systematic review was to summarise the findings of exercise training in modulating levels of ostensibly anabolic and catabolic hormones in adults aged > 40 years., Methods: We searched the following electronic databases (to July 2021) without a period limit: Cochrane Library, PubMed, Science Direct, Scopus, SPORTDiscus and Web of Science. Additionally, a manual search for published studies in Google Scholar was conducted for analysis of the 'grey literature' (information produced outside of traditional commercial or academic publishing and distribution channels). The initial search used the terms 'ageing' OR 'advanced age' OR 'old people' OR 'older' OR elderly' AND 'anabolic hormones' OR 'catabolic hormones' OR 'steroid hormones' OR 'sex hormones' OR 'testosterone' OR 'cortisol' OR 'insulin' OR 'insulin-like growth factor-1' OR 'IGF-1' OR 'sex hormone-binding globulin' OR 'SHBG' OR 'growth hormone' OR 'hGH' OR 'dehydroepiandrosterone' OR 'DHEA' OR 'dehydroepiandrosterone sulfate (DHEA-S)' AND 'exercise training' OR 'endurance training' OR 'resistance training' OR ' strength training' OR 'weight-lifting' OR 'high-intensity interval training' OR 'high-intensity interval exercise' OR 'high-intensity intermittent training' OR 'high-intensity intermittent exercise' OR 'interval aerobic training' OR 'interval aerobic exercise' OR 'intermittent aerobic training' OR 'intermittent aerobic exercise' OR 'high-intensity training' OR 'high-intensity exercise' OR 'sprint interval training' OR 'sprint interval exercise' OR 'combined exercise training' OR 'anaerobic training'. Only eligible full texts in English or French were considered for analysis., Results: Our search identified 484 records, which led to 33 studies for inclusion in the analysis. Different exercise training programs were used with nine studies using endurance training programs, ten studies examining the effects of high-intensity interval training, and 14 studies investigating the effects of resistance training. Most training programs lasted ≥ 2 weeks. Studies, regardless of the design, duration or intensity of exercise training, reported increases in testosterone, sex hormone-binding globulin (SHBG), insulin-like growth factor-1 (IGF-1), human growth hormone (hGH) or dehydroepiandrosterone (DHEA) (effect size: 0.19 < d < 3.37, small to very large) in both older males and females. However, there was no consensus on the effects of exercise on changes in cortisol and insulin in older adults., Conclusion: In conclusion, findings from this systematic review suggest that exercise training increases basal levels of testosterone, IGF-1, SHBG, hGH and DHEA in both male and females over 40 years of age. The increases in blood levels of these hormones were independent of the mode, duration and intensity of the training programs. However, the effects of long-term exercise training on cortisol and insulin levels in elderly people are less clear., (© 2021. Crown.)

Immunosenescence is characterized by deterioration of the immune system caused by aging which induces changes to innate and adaptive immunity. Immunosenescence affects function and phenotype of immune cells, such as expression and function of receptors for immune cells which contributes to loss of immune function (chemotaxis, intracellular killing). Moreover, these alterations decrease the response to pathogens, which leads to several age-related diseases including cardiovascular disease, Alzheimer's disease, and diabetes in older individuals. Furthermore, increased risk of autoimmune disease and chronic infection is increased with an aging immune system, which is characterized by a pro-inflammatory environment, ultimately leading to accelerated biological aging. During the last century, sedentarism rose dramatically, with a concomitant increase in certain type of cancers (such as breast cancer, colon, or prostate cancer), and autoimmune disease. Numerous studies on physical activity and immunity, with focus on special populations (i.e., people with diabetes, HIV patients) demonstrate that chronic exercise enhances immunity. However, the majority of previous work has focused on either a pathological population or healthy young adults whilst research in elderly populations is scarce. Research conducted to date has primarily focused on aerobic and resistance exercise training and its effect on immunity. This review focuses on the potential for exercise training to affect the aging immune system. The concept is that some lifestyle strategies such as high-intensity exercise training may prevent disease through the attenuation of immunosenescence. In this context, we take a top-down approach and review the effect of exercise and training on immunological parameters in elderly at rest and during exercise in humans, and how they respond to different modes of training. We highlight the impact of these different exercise modes on immunological parameters, such as cytokine and lymphocyte concentration in elderly individuals.

The current study examine the effects of combined sprint and resistance training on serum total testosterone (TT), sex-hormone-binding globulin (SHBG) and cortisol (C), at rest, and in response to the Wingate Anaerobic-Test (WAnT) in 21 and 41 years old men. Forty moderately-trained men were randomly assigned to a young trained (YT), young control (YC), middle-aged trained (MAT), and middle-aged control (MAC) group. Before (P1), and after (P2) training, blood samples were collected at rest and after exercise. At P1, higher C and lower TT was observed in middle-aged groups compared to younger ones (P < 0.05). At P2, basal TT increased significantly (P < 0.05) in MAT and the age-difference was absent between trained groups (P > 0.05). Basal SHBG decreased significantly in YT at P2 (P < 0.05) but did not change in other groups from before to after training (P > 0.05). Free-testosterone was significantly (P < 0.05) higher in young compared to middle-aged groups at P1, but at P2, this age-related difference disappeared between YT and MAT (P > 0.05). C post-WAnT increased significantly for MAT only (P < 0.05) at P2, whilst no significant changes were observed in the other three groups (P < 0.05) at P2. In contrast, resting levels of C did not change in all groups at P2 (P > 0.05). The current study demonstrates that this training intervention may help increase steroids hormones in middle-aged men and counteract the negative effect of age on TT and free testosterone., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Lifelong exercise is associated with regulation of skeletal mass and function, reductions in frailty, and successful aging. Yet, the influence of exercise on myostatin and myostatin-interacting factors is relatively under examined in older males. Therefore, we investigated whether serum total myostatin, free myostatin, follistatin, and growth and differentiation factor 11 (GDF11) were altered following high-intensity interval training (HIIT) in a group of 13 lifelong sedentary (SED; 64 [6] years) and 11 lifelong exercising (LEX; 62 [6] years) older males. SED follistatin was moderately greater than LEX pre-HIIT (Cohen's d  = 0.66), and was largely greater post-HIIT (Cohen's d  = 1.22). The HIIT-induced increase in follistatin was large in SED (Cohen's d  = 0.82) and absent in LEX (Cohen's d  = 0.03). GDF11 was higher in LEX pre-HIIT (Cohen's d  = 0.49) and post-HIIT (Cohen's d  = 0.63) compared to SED HIIT resulted in no change to GDF11 in LEX or SED (Cohen's d  = 0.00-0.03). Peak power output and GDF11 were correlated ( r  = 0.603), independent of grouping. Differences in GDF11 with lifelong exercise training, paired with the correlation between GDF11 and peak power output, suggested that GDF11 may be a relevant myostatin-interacting peptide to successful aging in humans, and strategies to maintain this need to be further explored., (© 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.)

Background: Testosterone, cortisol and their ratios may be indicators of anabolic status, but technical issues surrounding blood sampling has limited wider application. The advent of salivary testosterone (sal-T) analysis simplified sample acquisition, resulting in a subsequent rapid increase in the number of published research articles., Objective: The objective of this study was to undertake a meta-analysis to determine the effect of acute exercise bouts on post exercise sal-T and salivary cortisol (sal-C) concentrations and their ratio (sal-T:C)., Data Sources: Relevant databases such as PubMed, Web of Science, Science Direct and SPORTDiscus were searched up to and including 31 December 2013 for the term 'saliva AND testosterone AND exercise'., Study Selection: Studies (n = 21) selected from the 933 identified included randomised controlled trials (RCTs; n = 2), uncontrolled trials (UCTs; n = 18) and control trials (CTs; n = 1), all of which had an exercise component characterised as either aerobic, resistance or power training, each with acute sal-T and sal-C measurement obtained within 30 min of exercise bout completion., Study Appraisal and Synthesis Methods: A meta-analysis was conducted on change in sal-T, sal-C and the sal-T:C ratio following exercise using standard difference in means (SDM) and a random effects model., Results: For aerobic, resistance and power exercise, the overall SDMs for sal-T were 0.891, 1.061 and 0.509, respectively; for sal-C, the SDMs were 3.041, 0.773 and 1.200, respectively. For sal-T:C, the SDMs were -2.014, 0.027 and -0.968, respectively. RCTs, UCTs and CTs were separated by subgroup analysis. There were significant differences in overall weighted SDM values for sal-T between RCTs, UCTs and CTs within exercise modes. When examining aerobic exercise interventions, a quantitative interaction of study design was observed. RCTs resulted in a greater SDM than UCTs (1.337 vs. 0.446). Power interventions displayed a qualitative interaction with study design. UCTs where baseline measures were obtained 24 h before exercise had an SDM of -1.128, whereas UCTs where baseline was determined immediately prior to exercise had an SDM of 0.486. The single CT trial had an SDM of 2.260. Resistance exercise interventions were primarily UCTs; however, an observed influence of baseline sampling time whereby immediately pre- and 24 h pre-exercise resulted in differing SDMs. The sole resistance exercise RCTs resulted in the greatest SDM (2.500)., Conclusion: The current body of evidence regarding acute responses of sal-T to exercise is weak. This meta-analysis identifies varying exercise-dependent effect sizes. Each appear to be greatly influenced by study design and sample timing. There is a need for more RCTs and a standardised methodology for the measurement of salivary hormones in order to better determine the effect of exercise modality.

Introduction: Advancing age in men is associated with a progressive decline in serum testosterone (T) and interactions between exercise, aging and androgen status are poorly understood. The primary aim of this study was to establish the influence of lifelong training history on serum T, cortisol (C) and sex hormone binding globulin (SHBG) in aging men. A secondary aim was to determine the agreement between serum and salivary measurement of steroid hormones in ageing men., Methods: Serum and salivary steroid hormones (serum C, T and SHBG, and salivary measures of C and T) were determined and compared between two distinct groups; lifelong exercising males (LE [n = 20], 60.4 ± 4.7 year) and age matched lifelong sedentary individuals (SED [n = 28], 62.5 ± 5.3 years)., Results: T-test revealed a lack of significant differences for serum C or SHBG between LE and SED, while Mann-Whitney U revealed a lack of differences in total T (TT), bioavailable T (bio-T) or free testosterone (free-T). Further, salivary T (sal-T) did not correlate with serum markers of T in LE, SED, or when pooled (r = 0.040; p > 0.05)., Conclusions: Findings from this investigation suggested that resting levels of serum T and calculated free-T was unable to distinguish between diverse lifelong training histories in aging men. Further, sal-T was not an appropriate indicator of serum T and calculated free-T values in older males and considerable caution should be exercised when interpreting sal-T measurements in aging males.

Alteration in body composition, physical function, and substrate metabolism occur with advancing age. These changes can be attenuated by exercise. This study evaluated whether master athletes (MA [n = 20]) would have improved exercise capabilities, anthropometry, and hormone profiles when compared with age-matched sedentary counterparts (S [n = 28]). The MA group was predominantly aerobically trained with some resistance exercise incorporated in their routine. The VO(2max), peak power output, and salivary testosterone was significantly higher (p < 0.05) in the MA group, while diastolic blood pressure, systolic blood pressure, and body fat percentage were lower (p < 0.05). Cortisol, fat free mass, (FFM) and total body mass were not significantly different between groups. Salivary testosterone correlated positively with VO(2max) (r² = .320), suggesting that increased aerobic capacity is linked with higher concentrations of testosterone. These results suggest that life-long exercise is associated with favorable body composition and attenuation of the age related decline in testosterone.

Purpose: This meta-analysis aimed to (1) provide a comparison of peak changes in indirect markers of exercise-induced muscle damage (EIMD) in youths versus adults and (2) determine if the involved limb moderated this effect. Method: Studies were eligible for inclusion if they (1) provided a human youth versus adult comparison; (2) provided data on muscle strength, soreness, or creatine kinase markers beyond ≥24 hours; and (3) did not provide a recovery treatment. Effect sizes (ES) were presented alongside 95% confidence intervals. Results: EIMD exhibited larger effects on adults than in youths for muscle strength (ES = −2.01; P <.001), muscle soreness (ES = −1.52; P <.001), and creatine kinase (ES = −1.98; P <.001). The random effects meta-regression indicated that the effects of upper- and lower-limb exercise in youths and adults were significant for muscle soreness (coefficient estimate = 1.11; P <.001) but not for muscle strength or creatine kinase (P >.05). As such, the between-group effects for muscle soreness (ES = −2.10 vs −1.03; P <.05) were greater in the upper than lower limbs. Conclusion: The magnitude of EIMD in youths is substantially less than in their adult counterparts, and this effect is greater in upper than lower limbs for muscle soreness. These findings help guide practitioners who may be concerned about the potential impact of EIMD when training youth athletes. [ABSTRACT FROM AUTHOR]

Background: Sarcopenia is defined as a progressive and generalized loss of skeletal muscle quantity and function associated predominantly with aging. Physical activity appears the most promising intervention to attenuate sarcopenia, yet physical activity guidelines are rarely met. In recent years high intensity interval training (HIIT) has garnered interested in athletic populations, clinical populations, and general population alike. There is emerging evidence of the efficacy of HIIT in the young old (i.e. seventh decade of life), yet data concerning the oldest old (i.e., ninth decade of life onwards), and those diagnosed with sarcopenic are sparse. Objectives: In this scoping review of the literature, we aggregated information regarding HIIT as a potential intervention to attenuate phenotypic characteristics of sarcopenia. Eligibility Criteria: Original investigations concerning the impact of HIIT on muscle function, muscle quantity or quality, and physical performance in older individuals (mean age ≥60 years of age) were considered. Sources of Evidence: Five electronic databases (Medline, EMBASE, Web of Science, Scopus, and the Cochrane Central Register of Controlled Trials [CENTRAL]) were searched. Methods: A scoping review was conducted using the Arksey and O'Malley methodological framework (2005). Review selection and characterization were performed by two independent reviewers using pretested forms. Results: Authors reviewed 1,063 titles and abstracts for inclusion with 74 selected for full text review. Thirty-two studies were analyzed. Twenty-seven studies had a mean participant age in the 60s, two in the 70s, and three in the 80s. There were 20 studies which examined the effect of HIIT on muscle function, 22 which examined muscle quantity, and 12 which examined physical performance. HIIT was generally effective in Improving muscle function and physical performance compared to non-exercised controls, moderate intensity continuous training, or pre-HIIT (study design-dependent), with more ambiguity concerning muscle quantity. Conclusions: Most studies presented herein utilized outcome measures defined by the European Working Group on Sarcopenia in Older People (EWGSOP). However, there are too few studies investigating any form of HIIT in the oldest old (i.e., ≥80 years of age), or those already sarcopenic. Therefore, more intervention studies are needed in this population. [ABSTRACT FROM AUTHOR]

Objective: To determine the impact of prehabilitation on hospital length of stay, functional capacity, complications, and mortality after surgery in patients with hepatobiliary, colorectal, and upper gastrointestinal cancer. Background: ‘‘Prehabilitation’’ encompasses exercise, nutrition, and psychosocial interventions to optimize health before surgery. The benefits of prehabilitation are ill-defined. Methods: Medline, Embase and Cochrane Databases were searched systematically for the terms ‘‘prehabilitation AND exercise,’’ ‘‘perioperative care AND cancer surgery,’’ and ‘‘colorectal AND hepatobiliary AND hepatopancreatobiliary AND esophagogastric AND recovery AND outcomes.’’ Primary outcomes analyzed were hospital length of stay, functional capacity, significant postoperative complications (Clavien Dindo III), and mortality. A meta-analysis was conducted on the effect of all-modality prehabilitation for patients with colorectal, hepatopancreatobiliary and upper gastrointestinal cancer surgery using the raw mean difference, risk difference, and a randomeffects model. Results: Three hundred and seventy seven original titles were identified. Fifteen studies (randomized controlled trials; n ¼ 9 and uncontrolled trials; n ¼ 6) were included in the meta-analysis. Prehabilitation reduced hospital length of stay by 1.78 days versus standard care (95% CI: ]3.36, ]0.20, P < 0.05). There was no significant difference in functional capacity with prehabilitation determined using the 6-minute walk test (P ¼ 0.816) and no significant reduction in postoperative complications (P ¼ 0.378) or mortality rates (P ¼ 0.114). Conclusions: Prehabilitation was associated with reduced hospital length of stay but had no effect on functional capacity, postoperative complications, or mortality rates. Thus, prehabilitation should be recommended to accelerate recovery from cancer surgery, demonstrated by reduced hospital length of stay. [ABSTRACT FROM AUTHOR]

Background: The age-associated decrease in testosterone is one mechanism suggested to accelerate the aging process in males. Therefore, approaches to increase endogenous testosterone may be of benefit. The aim of this paper was to undertake a Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA)-accordant meta-analysis concerning the effect of exercise on total (TT), bioavailable (bio-T), free (free-T), and salivary (sal-T) testosterone in older males. Methods: Databases were searched up to and including 20th February 2018 for the terms "testosterone AND exercise AND aging AND males," "testosterone AND exercise AND old AND males," "testosterone AND training AND aging AND males," and "testosterone AND training AND old AND males". From 1259 originally identified titles, 22 studies (randomized controlled trials; RCTs; n = 9, and uncontrolled trials; UCTs; n = 13) were included which had a training component, participants ≥60 years of age, and salivary or serum testosterone as an outcome measure. Meta-analyses were conducted on change to testosterone following training using standardized difference in means (SDM) and random effects models. Results: The overall SDM for endurance training, resistance training, and interval training was 0.398 (95% CI = 0.034–0.761; P = 0.010), −0.003 (95% CI = −0.330–0.324; P = 0.986), and 0.283 (95% CI = 0.030–0.535; P = 0.028), respectively. Resistance training exhibited a qualitative effect of hormone fraction whereby free-T resulted in the greatest SDM (0.253; 95% CI = −0.043–0.549; P = 0.094), followed by TT (0.028; 95% CI = −0.204–0.260; P = 0.813), and resistance training negatively influenced bio-T (−0.373; 95% CI = −0.789–0.042; P = 0.078). Due to the small number of studies, subgroup analysis was not possible for endurance training and interval training studies. Conclusions: Data from the present investigation suggests that resistance training does not significantly influence basal testosterone in older men. Magnitude of effect was influenced by hormone fraction, even within the same investigation. Aerobic training and interval training did result in small, significant increases in basal testosterone. The magnitude of effect is small but the existing data are encouraging and may be an avenue for further research. [ABSTRACT FROM AUTHOR]

The aim of this investigation was to compare serum growth hormone (GH), insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein-3 (IGFBP-3) in response to a combined sprint and resistance training (CSRT) program in young and middle-aged men.Thirty-eight healthy, moderately trained men participated in this study. Young and middle-aged men were randomly assigned to, a young training group (YT = 10, 21.4±1.2yrs) ora young control group (YC = 9, 21.6±1.8 yrs), a middle-aged training group (MAT = 10, 40.4±2.1 yrs) or a middle-aged control group (MAC = 9, 40.5±1.8 yrs). Participants performed the Wingate Anaerobic Test (WAnT) before and after a 13-week CSRT program (three sessions per week). Blood samples were collected at rest, after warm-up, immediately post-WAnT, and 10 min post-WAnT. CSRT induced increases in GH at rest and in response to the WAnT in YT and MAT (P<0.05). CSRT-induced increases were observed for IGF-1 and IGFBP-3 at rest in MAT only (P<0.05). Pre-training, GH, IGF-1 and IGFBP-3 were significantly higher at rest and in response to the WAnT in young participants as compared to their middle-aged counterparts (P<0.05). Post-training, YT and MAT had comparable basal GH (P>0.05). In response to the WAnT, amelioration of the age-effect was observed between YT and MAT for IGF-1 and IGF-1/IGFBP-3 ratio following CSRT (P>0.05). These data suggest that CSRT increases the activity of the GH/IGF-1 axis at rest and in response to the WAnT in young and middle-aged men. In addition, CSRT reduces the normal age-related decline of somatotropic hormones in middle-age men. [ABSTRACT FROM AUTHOR]

Testosterone is an important biological hormone, which displays a gradual decline with advancing age. Exercise training has been proposed as a first-line therapy for biochemical hypogonadism (clinically low serum testosterone). As such, the present investigation compared the incidence of biochemical hypogonadism (total testosterone <11.3 nmol·L-1) in a cohort of otherwise healthy lifelong sedentary men (SED [N=24], 63±5 years), compared with a positive control group of lifelong exercisers (LEX [N=16], 60±5 years) using electrochemiluminescent immunoassay. Fisher's exact test identified significantly more of the SED group were classified as biochemically hypogonadal than the LEX group (8/24 compared to 2/16 respectively; p<.05). These data provide preliminary evidence that exercise may protect against the development of low testosterone defined hypogonadism in aging men. [ABSTRACT FROM AUTHOR]

Introduction:The aim of this investigation was to examine the impact high-intensity interval training (HIIT) on serum insulin-like growth factor-I (IGF-I) in active compared with sedentary aging men. Methods:22 lifetime sedentary (SED; 62 ± 2 years) and 17 masters’ athletes (LEX; 60 ± 5 years) were recruited to the study. As HIIT requires preconditioning exercise in sedentary cohorts, the study required three assessment phases; enrollment (phase A), following preconditioning exercise (phase B), and post-HIIT (phase C). Serum IGF-I was determined by electrochemiluminescent immunoassay. Results:IGF-I was higher in LEX compared to SED at baseline (p = 0.007, Cohen’sd = 0.91), and phase B (p = 0.083, Cohen’sd = 0.59), with only a small difference at C (p = 0.291, Cohen’sd = 0.35). SED experienced a small increase in IGF-I following preconditioning from 13.1 ± 4.7 to 14.2 ± 6.0 μg·dl−1(p = 0.376, Cohen’sd = 0.22), followed by a larger increase post-HIIT (16.9 ± 4.4 μg·dl−1), which was significantly elevated compared with baseline (p = 0.002, Cohen’sd = 0.85), and post-preconditioning (p = 0.005, Cohen’sd = 0.51). LEX experienced a trivial changes in IGF-I from A to B (18.2 ± 6.4 to 17.2 ± 3.7 μg·dl−1[p = 0.538, Cohen’sd = 0.19]), and a small change post-HIIT (18.4 ± 4.1 μg·dl−1[p = 0.283, Cohen’sd = 0.31]). Small increases were observed in fat-free mass in both groups following HIIT (p < 0.05, Cohen’sd = 0.32–0.45). Conclusions:In conclusion, HIIT with preconditioning exercise abrogates the age associated difference in IGF-I between SED and LEX, and induces small improvements in fat-free mass in both SED and LEX. [ABSTRACT FROM PUBLISHER]

Introduction: Advancing age is associated with a gradual decline in circulating androgens, and the putative role of exercise training on systemic androgens remains to be adequately defined.Methods: The present investigation examined the impact of 6 weeks of supervised exercise training on resting levels of systemic hormones in a cohort of lifelong sedentary men [SED (n = 28), 62.5 ± 5.3 years], compared with a positive control group of age-matched lifelong exercisers [LE (n = 20), 60.4 ± 4.7 years, >30 years training history]. Blood hormones were sampled pre- and post-intervention from an antecubital forearm vein and analysed using electrochemiluminescent immunoassay. Cardiorespiratory fitness ([Formula: see text]) was determined via indirect calorimetry during an incremental cycle test to volitional exhaustion.Results: Analysis of variance (ANOVA) revealed a lack of significant change in any parameter amongst LE, whilst SED experienced a significant exercise-induced improvement in cardiorespiratory fitness and total testosterone (all p < 0.05). Concurrent increases in sex hormone-binding globulin (SHBG; p < 0.05) resulted in a lack of change to either bioavailable or calculated free testosterone (p > 0.05) amongst SED.Conclusions: Although resting levels of systemic total testosterone increased in response to 6 weeks of exercise training, increases in SHBG negated any potential relationship between calculated-free or bioavailable testosterone. These findings indicate that increases in bioavailable testosterone fraction are not required for cardiorespiratory fitness improvements in aging men. [ABSTRACT FROM AUTHOR]

This study examined the effect of exercise- and heat-induced dehydration on strength, jump capacity and neuromuscular function. Twelve recreationally active males completed six resistance exercise bouts (baseline and after each 5 exposure sessions) in an increasing state of hypohydration obtained by repeated heat exposure and exercise sessions (5 periods of 20 min jogging at up to approximately 80% age predicted heart rate maximum at 48.5 +/- 0.48 degrees C, relative humidity 50 +/- 4%). Relative to starting values, body mass decreased 1.0 +/- 0.5, 1.9 +/- 0.7, 2.6 +/- 0.8, 3.3 +/- 0.9 and 3.9 +/- 1.0% after exposure 1, 2, 3, 4 and 5, respectively. However, plasma volume remained constant. No significant differences existed amongst trials in vertical jump height, electromyography data or isokinetic leg extension at a rate of 120 degrees s(-1). Isometric leg extensions were significantly reduced (P < 0.05) after the first (1% body mass loss) and subsequent exposures in comparison to baseline. Isokinetic leg extensions at a rate of 30 degrees s(-1) were significantly reduced after the third (2.6% body mass loss) and subsequent exposures compared with baseline. No dose response was identified in any of the tested variables yet a threshold was observed in isometric and isokinetic strength at 30 degrees s(-1). In conclusion, dehydration caused by jogging in the heat had no effect on vertical jumping or isokinetic leg extensions at a rate of 120 degrees s(-1). Alternatively, exercise-induced dehydration was detrimental to isometric and isokinetic leg extensions at a rate of 30 degrees s(-1), suggesting the force-velocity relationship in hypohydration merits further research. [ABSTRACT FROM AUTHOR]

Long-term implications of acutely increased cardiorespiratory fitness following short-term exercise interventions in older adults are unknown. In this study, we examined peak oxygen uptake (VO 2peak) after 4-years of 'free-living' after a high intensity interval training (HIIT) intervention. Seventeen lifelong exercisers (LEX) and 17 previously sedentary (SED) males (55–74 years of age in 2012) were tested four years (phase D) after our previous experiment which included 6-weeks of aerobic moderate intensity exercise (phase B), followed by 6-weeks of HIIT (phase C). At all stages, a standard incremental exercise protocol on a cycle ergometer was completed to determine VO 2peak. SED (P = 1.000, Cohen's d = 0.01) and LEX (P = 1.000, Cohen's d = 0.11) VO 2peak at phase D was not different from phase A (enrolment). SED experienced a large decrease in VO 2peak from phase C to phase D (32 ± 6 ml·kg·min−1 to 27 ± 6 ml·kg·min−1 [P < 0.001, Cohen's d = 0.81]). LEX experienced a small decrease in VO 2peak from phase C to phase D (42 ± 7 ml·kg·min−1 to 39 ± 9 ml·kg·min−1 [P < 0.001, Cohen's d = 0.46]). At phase D, LEX had greater VO 2peak than SED (P < 0.001, Cohen's d = 1.73). The proportion of subjects who reported discontinuing training, maintaining moderate training, and maintaining HIIT differed between groups (P = 0.023), with LEX self-reporting more HIIT, and SED self-reporting more discontinuation from exercise. Those who continued exercising experienced a reduction in VO 2peak over the four years from 39 ± 7 ml·kg·min−1 to 36 ± 9 ml·kg·min−1 (N = 25, P < 0.001, Cohen's d = 0.37), and those who discontinued exercising also experienced a reduction in VO 2peak from 30 ± 7 ml·kg·min−1 to 25 ± 9 ml·kg·min−1 (N = 9, P = 0.003, Cohen's d = 0.62). Four years after completing a brief period of aerobic exercise and HIIT, older males demonstrated a preservation of VO 2peak , irrespective of training status (LEX or SED). However, LEX exhibited greater VO 2peak than SED after 4-years of unsupervised 'free-living'. Notably, participants who discontinued exercising experienced a greater reduction in VO 2peak. These data suggest that a 6 weeks of supervised HIIT can facilitate the long term. • 12 weeks of aerobic and HIIT preserved VO 2peak over four years. • This combination increased and maintained VO 2peak in the short- and long-term. • Short-term increased VO 2peak appears a catalyst for maintained VO 2peak over years. • VO 2peak was preserved irrespective of initial exercise training status. • Lifelong exercisers had higher VO 2peak throughout compared with sedentary older men. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate whether 6 weeks' high intensity interval training (HIIT; 6 × 30 s sprints at 40% peak power, once every five days) following 6 weeks' of aerobic preconditioning could favourably affect fasting insulin, glucose, and the homeostatic model assessment of insulin resistance (HOMA1-IR) in sedentary older men compared with masters athletes. A secondary aim was to establish whether lifelong exercisers (LEX) exhibited improved fasting insulin, glucose, and HOMA1-IR, compared to sedentary older males (SED). Twenty-two males (62 ± 2 years) comprised the SED group and 17 males (60 ± 5 years) were enrolled as LEX. Participants were tested at phase A (baseline), B (after preconditioning), and C (post-HIIT). There was no effect of time (P = 0.116) or interaction (P = 0.727) on insulin. However, there was an effect of group (P < 0.001). In terms of magnitude, HIIT induced a small decrease in SED insulin compared to baseline (15.8 ± 8.1 uIU·ml−1 at baseline and 14.0 ± 7.8 uIU·ml−1 post-HIIT; Cohen's d = 0.23) and compared to post-preconditioning (17.5 ± 9.7 uIU·ml−1; Cohen's d = 0.40). LEX insulin was unchanged throughout (all differences were trivial). Insulin was lower in LEX than SED at phase A (P < 0.001, Cohen's d = 1.31), B (P = 0.023, Cohen's d = 0.78), and C (P = 0.004, Cohen's d = 1.01). There was no effect of time (P = 0.290), group (P = 0.166), or interaction (P = 0.153) for glucose. In terms of magnitude, HIIT produced a small reduction in SED glucose compared to baseline (5.7 ± 1.3 mmol·l−1 at baseline and 5.3 ± 0.9 mmol·l−1 post-HIIT; Cohen's d = 0.36), and compared to phase B (5.6 ± 0.8 mmol·l−1, Cohen's d = 0.35). LEX glucose was unchanged throughout (all changes were trivial). SED had moderately higher blood glucose than LEX at phase A (Cohen's d = 0.49), and B (Cohen's d = 0.63), but only a trivial difference existed at phase C (Cohen's d = 0.15). There was no effect of time (P = 0.110), or interaction (P = 0.569) on HOMA1-IR. However, there was an effect of group (P = 0.002). In terms of magnitude, SED HOMA1-IR was unchanged from phase A to B (4.2 ± 3.0 and 4.5 ± 2.9 arbitrary units respectively [Cohen's d = 0.10]). However, at C (3.5 ± 2.6) there was a small decrease compared to B (Cohen's d = 0.36), and A (Cohen's d = 0.25). LEX experienced a small increase in HOMA1-IR from phase A to B (1.6 ± 1.3 and 2.3 ± 2.8 respectively [Cohen's d = 0.32]), followed by a small decrease from B to C (1.7 ± 1.1 at phase C [Cohen's d = 0.28]), and a trivial change from A to C (Cohen's d = 0.08). HOMA1-IR was lower in LEX than SED at baseline (P = 0.002, Cohen's d = 1.12), after preconditioning (P = 0.024, Cohen's d = 0.77), and post-HIIT (P = 0.014, Cohen's d = 0.90). Results of this study provide preliminary evidence that HIIT preceded by preconditioning can induce small improvements in fasting insulin, glucose, and HOMA1-IR in sedentary older men compared with masters athletes. • HIIT induced a small reduction in fasting insulin in sedentary older men. • HIIT produced a small decrease in fasting glucose in sedentary older men. • HIIT caused a small improvement in HOMA-IR in sedentary older men. • Few individuals improved clinical status (diabetic, impaired fasting glucose) with HIIT. • Lifelong exercisers had superior glucoregulatory biomarkers than sedentary males. [ABSTRACT FROM AUTHOR]