Skip Navigation LinksHome > June 2008 - Volume 40 - Issue 6 > Effect of Ambient Temperature on Cardiovascular Drift and Ma...
Medicine & Science in Sports & Exercise:
doi: 10.1249/MSS.0b013e3181666ed7
BASIC SCIENCES: Original Investigations

Effect of Ambient Temperature on Cardiovascular Drift and Maximal Oxygen Uptake

LAFRENZ, ANDREW J.1; WINGO, JONATHAN E.2; GANIO, MATTHEW S.3; CURETON, KIRK J.4

Collapse Box

Abstract

Purpose: This study tested the hypothesis that the magnitude of cardiovascular (CV) drift and decrease in maximal oxygen uptake (V˙O2max) would be greater at 35°C than at 22°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˙O2max (CV drift) was measured in hot (HEAT, 35°C) and cool (COOL, 22°C) ambient temperatures in 10 endurance-trained men (age = 23 ± 3 yr, V˙O2max = 64.7 ± 8.7 mL·kg−1·min−1). V˙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˙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˙O2max was greater (P < 0.05) in HEAT versus COOL. HR increased 11% (P < 0.05), SV decreased 11% (P < 0.05), and V˙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˙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˙O2max measured immediately thereafter is greater in a hot than in a cool environment.

©2008The American College of Sports Medicine

Login

Article Tools

Share

Search for Similar Articles
You may search for similar articles that contain these same keywords or you may modify the keyword list to augment your search.

Connect With Us