PURPOSE: This study tested the hypothesis that the magnitude of cardiovascular (CV) drift and decrease in maximal oxygen uptake (V[spacing dot above]O2max) would be greater at 35 degrees C than at 22 degrees C. METHODS: The increase in HR and decrease in stroke volume (SV) between 15 and 45 min of cycling at 59.2 +/- 1.9% V[spacing dot above]O2max (CV drift) was measured in hot (HEAT, 35 degrees C) and cool (COOL, 22 degrees C) ambient temperatures in 10 endurance-trained men (age = 23 +/- 3 yr, V[spacing dot above]O2max = 64.7 +/- 8.7 mL.kg.min). V[spacing dot above]O2max was measured immediately after the 45 min of cycling and again under both ambient temperature conditions on separate days after 15 min of cycling. This design permitted assessment of V[spacing dot above]O2max between the same time points that CV drift occurred. Fluid to replace sweat losses was provided during all trials. RESULTS: CV drift and the associated decrease in V[spacing dot above]O2max was greater (P < 0.05) in HEAT versus COOL. HR increased 11% (P < 0.05), SV decreased 11% (P < 0.05), and V[spacing dot above]O2max fell 15% (P < 0.05) between 15 and 45 min in HEAT, whereas HR and SV changed less (+2% and -2% for HR and SV, respectively, P < 0.05), and there was no significant decrease in V[spacing dot above]O2max (5%, P > 0.05) between 15 and 45 min in COOL. CONCLUSION: These data demonstrate the magnitude of CV drift during prolonged submaximal exercise, and the accompanying decrease in V[spacing dot above]O2max measured immediately thereafter is greater in a hot than in a cool environment.
PURPOSE: This study tested the hypothesis that the magnitude of cardiovascular (CV) drift and decrease in maximal oxygen uptake (V[spacing dot above]O2max) would be greater at 35 degrees C than at 22 degrees C. METHODS: The increase in HR and decrease in stroke volume (SV) between 15 and 45 min of cycling at 59.2 +/- 1.9% V[spacing dot above]O2max (CV drift) was measured in hot (HEAT, 35 degrees C) and cool (COOL, 22 degrees C) ambient temperatures in 10 endurance-trained men (age = 23 +/- 3 yr, V[spacing dot above]O2max = 64.7 +/- 8.7 mL.kg.min). V[spacing dot above]O2max was measured immediately after the 45 min of cycling and again under both ambient temperature conditions on separate days after 15 min of cycling. This design permitted assessment of V[spacing dot above]O2max between the same time points that CV drift occurred. Fluid to replace sweat losses was provided during all trials. RESULTS: CV drift and the associated decrease in V[spacing dot above]O2max was greater (P < 0.05) in HEAT versus COOL. HR increased 11% (P < 0.05), SV decreased 11% (P < 0.05), and V[spacing dot above]O2max fell 15% (P < 0.05) between 15 and 45 min in HEAT, whereas HR and SV changed less (+2% and -2% for HR and SV, respectively, P < 0.05), and there was no significant decrease in V[spacing dot above]O2max (5%, P > 0.05) between 15 and 45 min in COOL. CONCLUSION: These data demonstrate the magnitude of CV drift during prolonged submaximal exercise, and the accompanying decrease in V[spacing dot above]O2max measured immediately thereafter is greater in a hot than in a cool environment.
Authors: Matthew S Ganio; Evan C Johnson; Jennifer F Klau; Jeffrey M Anderson; Douglas J Casa; Carl M Maresh; Jeff S Volek; Lawrence E Armstrong Journal: Eur J Appl Physiol Date: 2010-12-01 Impact factor: 3.078
Authors: Carlo Ferri Marini; Ario Federici; James S Skinner; Giovanni Piccoli; Vilberto Stocchi; Luca Zoffoli; Luca Correale; Stefano Dell'Anna; Carlo Alberto Naldini; Matteo Vandoni; Francesco Lucertini Journal: PeerJ Date: 2022-04-25 Impact factor: 3.061