Antonia Kaltsatou1, Andreas D Flouris1,2, Christophe L Herry3, Sean R Notley2, Andrew J E Seely3,4, Heather Wright Beatty2, Glen P Kenny5,6. 1. FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100, Trikala, Greece. 2. Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University Private, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada. 3. Clinical Epidemiological Program of the Ottawa Hospital Research Institute, Ottawa, ON, Canada. 4. Thoracic Surgery and Critical Care Medicine, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, Canada. 5. Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University Private, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada. gkenny@uottawa.ca. 6. Clinical Epidemiological Program of the Ottawa Hospital Research Institute, Ottawa, ON, Canada. gkenny@uottawa.ca.
Abstract
PURPOSE: This study aimed to detect potential differences in heart-rate variability (HRV) during a moderate-intensity intermittent exercise in the heat among physically active young (25.8 ± 1.9 years), middle-aged (43.5 ± 2.8 years), and older (62.9 ± 3.7 years) men. METHODS: Thirty-three participants (11/group) performed four successive bouts of 15-min cycling at a moderate fixed rate of metabolic heat production of ~ 400 W; each separated by a 15-min recovery with 1 h of final recovery in a hot and dry environment (35 °C, 20% relative humidity). Twelve HRV indices were computed that have been commonly described in the literature, and characterized various domains of the variability and complexity of heart rate. RESULTS:Cardiac autonomic regulation during intermittent exercise in the heat, as well as during pre-exercise rest and recovery was significantly affected by age, as changes were observed among the three different aged groups in five indices (p ≤ 0.05). Similarly, time influenced cardiac autonomic regulation as three indices showed changes across time (p ≤ 0.05) during intermittent exercise, whilst five indices displayed significant changes (p ≤ 0.05) during rest and recovery in the heat. CONCLUSIONS: This study supports that moderate-intensity intermittent exercise in the heat is associated with significant cardiac autonomic dysregulation in older men, as compared to young and middle-aged men, yet it highlights the importance of developing preventative health strategies for heat-related illness in aged individuals.
RCT Entities:
PURPOSE: This study aimed to detect potential differences in heart-rate variability (HRV) during a moderate-intensity intermittent exercise in the heat among physically active young (25.8 ± 1.9 years), middle-aged (43.5 ± 2.8 years), and older (62.9 ± 3.7 years) men. METHODS: Thirty-three participants (11/group) performed four successive bouts of 15-min cycling at a moderate fixed rate of metabolic heat production of ~ 400 W; each separated by a 15-min recovery with 1 h of final recovery in a hot and dry environment (35 °C, 20% relative humidity). Twelve HRV indices were computed that have been commonly described in the literature, and characterized various domains of the variability and complexity of heart rate. RESULTS: Cardiac autonomic regulation during intermittent exercise in the heat, as well as during pre-exercise rest and recovery was significantly affected by age, as changes were observed among the three different aged groups in five indices (p ≤ 0.05). Similarly, time influenced cardiac autonomic regulation as three indices showed changes across time (p ≤ 0.05) during intermittent exercise, whilst five indices displayed significant changes (p ≤ 0.05) during rest and recovery in the heat. CONCLUSIONS: This study supports that moderate-intensity intermittent exercise in the heat is associated with significant cardiac autonomic dysregulation in older men, as compared to young and middle-aged men, yet it highlights the importance of developing preventative health strategies for heat-related illness in aged individuals.
Entities:
Keywords:
Ageing; Autonomic nervous system; Exercise; Heart-rate variability; Hot environment
Authors: Andreas D Flouris; Andrea Bravi; Heather E Wright-Beatty; Geoffrey Green; Andrew J Seely; Glen P Kenny Journal: Eur J Appl Physiol Date: 2014-01-05 Impact factor: 3.078
Authors: Glen P Kenny; Martin P Poirier; George S Metsios; Pierre Boulay; Sheila Dervis; Brian J Friesen; Janine Malcolm; Ronald J Sigal; Andrew J E Seely; Andreas D Flouris Journal: Temperature (Austin) Date: 2016-08-31