Daniel Snape, Barney Wainwright, Iain T Parsons, Michael J Stacey, David R Woods, John O'Hara
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引用次数: 0
Abstract
A mixed-method heat acclimation (HA) protocol may optimise performance by supporting the training taper while promoting thermal adaptation; however, the impact on cardiovascular and fluid-regulatory adjustments to protect health is unknown. Therefore, we examined the effects of a mixed-method heat protocol on physiological responses, including cardiovascular and fluid-regulatory strain with exercise-heat stress, and self-paced performance in the heat. Twenty (15 males, five females) triathletes were randomised to 8 days of HA (HOT), or exercise in thermoneutral conditions (TEMP). A heat stress test (HST) comprising 45 min of cycling in a climatic chamber (32°C, 70% relative humidity) was performed on days 1, 5 (HOT only) and 8. Before and after the intervention, a cycling time trial was conducted in the same climatic conditions (days 0 and 10). Venous blood samples were analysed at rest and post-HST (days 1 and 8 only) for the catecholamine product normetanephrine and the vasopressin surrogate copeptin. Following 7 days of HA (days 1 vs. 8) resting rectal temperature was significantly lower in the HOT compared to the TEMP group (-0.32 ± 0.36°C, P = 0.002). Normetanephrine was 24.3% lower after 7 days of HA (P = 0.012), and copeptin was 53.4% lower at the post-HST time point (HOT vs. TEMP, P = 0.012). However, HA had no effect (0.3%, P = 0.984) on self-paced performance in the heat. Mixed-method HA elicited a progressive reduction in cardiovascular strain and a net reduction in fluid-regulatory strain without improving self-paced performance in the heat.
期刊介绍:
Experimental Physiology publishes research papers that report novel insights into homeostatic and adaptive responses in health, as well as those that further our understanding of pathophysiological mechanisms in disease. We encourage papers that embrace the journal’s orientation of translation and integration, including studies of the adaptive responses to exercise, acute and chronic environmental stressors, growth and aging, and diseases where integrative homeostatic mechanisms play a key role in the response to and evolution of the disease process. Examples of such diseases include hypertension, heart failure, hypoxic lung disease, endocrine and neurological disorders. We are also keen to publish research that has a translational aspect or clinical application. Comparative physiology work that can be applied to aid the understanding human physiology is also encouraged.
Manuscripts that report the use of bioinformatic, genomic, molecular, proteomic and cellular techniques to provide novel insights into integrative physiological and pathophysiological mechanisms are welcomed.