October 11, 2018
Anthony S. Leicht 1, Aaron Halliday1, Wade H. Sinclair 1, Shaun D’Auria2, Martin Buchheit3, Glen P. Kenny4, Jamie Stanley5
1 Sport and Exercise Science, James Cook University, Townsville, 4811 Australia
2 Performance Science, Queensland Academy of Sport, Brisbane, 4811 Australia
3 Sport Science Unit, Myorobie Association, Montvalezan, 73700, France
4 Human and Environmental Physiology Research Unit, University of Ottawa, ON, K1N 6N5 Canada
5 Physiology Department, South Australian Sport Institute, Adelaide, 5025 Australia
The use of heat exposure has been a growing area of scientific interest with performance and health benefits reported for adults. Athletes typically undertake exercise in the heat to develop adaptations that lead to improved performance. However, the combination of exercise and heat during training may reduce training quality with alternative, non-exercise and heat protocols (e.g. sauna) appealing to athletes. Repeated use of sauna has been reported to improve cardiovascular health in adults with these changes possibly a result of alterations in the neural control of the heart. These neural changes may lead to enhanced performance in athletes. Consequently, the aim of this study was to examine the effects of passive, post-exercise, sauna bathing on the neural control of the heart (i.e. cardiac neural control) during each sauna session of a 10-day training period. It was anticipated that this study would identify the benefits of sauna on cardiac neural control but also identify the minimum number of sessions to see this benefit.
Six well-trained, male cyclists completed their normal daily training (~1 hour) followed by a 30-minute sauna session (~87°C, ~11% relative humidity) each day of a 10-day training block. During each sauna session, heart rate was recorded via a standard chest monitor with cardiac neural control assessed by the change in resting heart rate and a measure of heart rate variability (HRV, difference in time between adjacent normal heart beats) every 10 minutes. During the first sauna session, heart rate increased by 32% over time with a simultaneous reduction in HRV of ~62%. Similar changes in heart rate and HRV were observed during each subsequent sauna bout indicating a lack of short-term training adaptation for athletes. High levels of cardiac neural control in well-trained athletes and the volume of heat stress during the 10-day training period were discussed as possible contributors to the limited training change. Further work is needed to confirm the effective impact of sauna bathing on HRV adaptations and the influence of heat stress volume on such adaptations.
- Exposure to intense heat, such as that during a sauna, resulted in an increased heart rate with a concurrent reduction in cardiac neural control in well-trained cyclists;
- Daily exposure to sauna resulted in similar changes in heart rate and cardiac neural control indicating a lack of short-term training adaptation for cyclists;
- Trained athletes can tolerate intense sauna heat with the volume of heat stress likely a key factor for training adaptations for well-trained cyclists.
Anthony Leicht, Aaron Halliday, Wade Sinclair, Shaun D’Auria, Martin Buchheit, Glen Kenny and Jamie Stanley. Heart rate variability responses to acute and repeated postexercise sauna in trained cyclists Appl Physiol Nutr Metab. Published on the web 14 February 2018, doi/10.1139/apnm-2017-0581
This article is a summary of an article published in Applied Physiology, Nutrition & Metabolism. If you intend to cite any information in this article, please consult the original article and cite that source. This summary was written for the Canadian Society for Exercise Physiology and it has been reviewed by the CSEP Knowledge Translation Committee.