Search

Abstract Post‐exercise hot (HWI) and cold (CWI) water immersion are popular strategies used by athletes in a range of sporting contexts, such as enhancing recovery or adaptation. However, prolonged heating bouts increase neuroendocrine responses that are associated with perceptions of fatigue. Fourteen endurance‐trained runners performed three trials consisting of two 45‐min runs at 95% lactate threshold on a treadmill separated by 6 h of recovery. Following the first run, participants completed one of HWI (30 min, 40°C), CWI (15 min, 14°C) or control (CON, 30 min rest in ambient conditions) in a randomised order. Perceived effort and recovery were measured using ratings of perceived exertion (RPE) and the Acute Recovery and Stress Scale (ARSS), whilst physiological responses including venous concentrations of a range of neuroendocrine markers, superficial femoral blood flow, heart rate and rectal temperature were measured. Exercise increased neuroendocrine responses of interleukin‐6, adrenaline and noradrenaline (all P 0.05), nor RPE (P = 0.68), despite differences in rectal temperature, superficial femoral blood flow following the first run, and participants’ expected recovery prior to the intervention (all P

Abstract Background and Aims Arterial function (specifically arterial stiffness) is an important cardiovascular risk factor. Pulse wave velocity (PWV) and augmentation index (Alx) are established indicators of arterial function. The present study aimed to evaluate the repeatability and reproducibility of PWV and Alx in healthy individuals. Methods Forty healthy participants (age 33 ± 11 years, 17 females) underwent resting supine PWV and Alx assessments. Measurements were made in triplicate and repeated 1 week apart. Alx was measured by brachial occlusion and PWV was measured from the carotid artery to the femoral artery via the tonometer‐oscillometric method. Repeatability and reproducibility were assessed using the intraclass correlation coefficient (ICC). Interoperator reproducibility was performed on 10 participants. Results The average values for week‐to‐week visits for PWV and Alx were 6.20 ± 0.91 versus 6.13 ± 0.91 ms−1 and 14.0 ± 11.8 versus 16.3 ± 12.2% respectively. For same‐day measurements, both PWV and Alx showed excellent repeatability (PWV: ICC = 0.96, 95% CI: 0.92–0.98, p

Abstract Hot water immersion improves cardiovascular health and sporting performance, yet its adverse responses are understudied. Thirteen young and 17 middle‐aged adults (n = 30) were exposed to 2 × 30 min bouts of whole‐body 39°C water immersion. Young adults also completed cooling mitigation strategies in a randomized cross‐over design. Orthostatic intolerance and selected physiological, perceptual, postural and cognitive responses were assessed. Orthostatic hypotension occurred in 94% of middle‐aged adults and 77% of young adults. Young adults exhibited greater dizziness upon standing (young subjects, 3 out of 10 arbitrary units (AU) vs. middle‐aged subjects, 2 out of 10 AU), with four terminating the protocol early owing to dizziness or discomfort. Despite middle‐aged adults being largely asymptomatic, both age groups had transient impairments in postural sway after immersion (P

Abstract Background and Aims Single‐use electrocardiography (ECG) leads have been developed to reduce healthcare‐associated infection. This study compared the validity and reliability of short‐term heart rate variability (HRV) obtained from single‐use disposable ECG leads. Methods Thirty healthy subjects (33 ± 10 years; 9 females) underwent 5‐min resting HRV assessments using disposable (single use) ECG cable and wire system (Kendall DL™ Cardinal Health) and a standard, reusable ECG leads (CardioExpress, Spacelabs Healthcare). Results Intraclass correlation coefficient (ICC) with 95% confidence interval (CI) between disposable and reusable ECG leads was for the time domain [R‐R interval (ms); 0.99 (0.91, 1.00)], the root mean square of successive normal R‐R interval differences (RMSSD) (ms); 0.91 (0.76, 0.96), the SD of normal‐to‐normal R‐R intervals (SDNN) (ms); 0.91 (0.68, 0.97) and frequency domain [low‐frequency (LF) normalized units (nu); 0.90 (0.79, 0.95), high frequency (HF) nu; 0.91 (0.80, 0.96), LF power (ms2); 0.89 (0.62, 0.96), HF power (ms2); 0.90 (0.72, 0.96)] variables. The mean difference and upper and lower limits of agreement between disposable and reusable leads for time‐ and frequency‐domain variables were acceptable. Analysis of repeated measures using disposable leads demonstrated excellent reproducibility (ICC 95% CI) for R‐R interval (ms); 0.93 (0.85, 0.97), RMSSD (ms); 0.93 (0.85, 0.97), SDNN (ms); 0.88 (0.75, 0.95), LF power (ms2); 0.87 (0.72, 0.94), and HF power (ms2); 0.88 (0.73, 0.94) with coefficient of variation ranging from 2.2% to 5% (p > 0.37 for all variables). Conclusion Single‐use Kendall DL™ ECG leads demonstrate a valid and reproducible tool for the assessment of HRV.