Abstract Title

The Effect of Heat Exposure on Heart Rate and VO2 during Time to Exhaustion Exercise

Abstract

Purpose:The purpose of this study was to examine the effects of heat exposure on heart rate and VO2during a time to exhaustion (TTE) exercise bout. Methods:Eleven college-age men completed 3 experimental trials: a VO2max test and cycling trials at 90% VO2max in 22°C (MT) and 35°C (HT). The TTE exercise followed a 60-minute steady state at 60% VO2max and continued until volitional fatigue. Heart rate and VO2were measured continuously during the TTE. PRE, MID, and POST time points were calculated for each participant based on their individual TTE. Data were analyzed using repeated measures ANOVA. Results:There was a significant interaction for heart rate (F=6.180, p=0.024, h2=0.382). Heart rate increased from PRE to MID to POST for both MT and HT (p<0.001). In addition, heart rate was significantly greater in HT (159.82 +17.47) compared to MT (146.09 +20.70) at PRE (p=0.031). There was also a significant interaction for VO2(F=4.312, p=0.030, h2=0.324). VO2also increased from PRE to MID to POST for both MT and HT (p< 0.05). In addition, VO2was significantly greater in MT (3.30 +0.52) vs HT (3.05 +0.33) at POST (p=0.025). There was a significant difference in TTE between conditions (p=0.008) with MT (303.00 +121.20 seconds) being significantly longer than HT (174.00 +54.41 seconds). Conclusions:This data suggests that the participants were able to perform at a higher intensity and for a longer duration in MT compared to HT.

Modified Abstract

Purpose:To examine the effects of heat exposure on heart rate (HR) and VO2during a time to exhaustion (TTE) exercise bout. Methods:College-age men completed 3 experimental trials: a VO2max test and cycling trials, 90% VO2max in 22°C (MT) and 35°C (HT). TTE exercise continued until volitional fatigue while HR and VO2were measured continuously. PRE, MID, and POST time points were also calculated for each participant. Results:HR was significantly greater in HT compared to MT at PRE, while VO2was significantly greater in MT vs HT at POST. TTE was significantly longer in MT than HT. Conclusions:This data suggests that the participants were able to perform at a higher intensity and for a longer duration in MT compared to HT.

Research Category

Social Science/Education/Public Health

Author Information

Tori HargettFollow

Primary Author's Major

Exercise Science

Mentor #1 Information

Dr. Adam

Jajtner

Mentor #2 Information

Dr. Kylene

Boka

Start Date

April 2019

Research Area

Exercise Physiology | Exercise Science

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Apr 9th, 1:00 PM

The Effect of Heat Exposure on Heart Rate and VO2 during Time to Exhaustion Exercise

Purpose:The purpose of this study was to examine the effects of heat exposure on heart rate and VO2during a time to exhaustion (TTE) exercise bout. Methods:Eleven college-age men completed 3 experimental trials: a VO2max test and cycling trials at 90% VO2max in 22°C (MT) and 35°C (HT). The TTE exercise followed a 60-minute steady state at 60% VO2max and continued until volitional fatigue. Heart rate and VO2were measured continuously during the TTE. PRE, MID, and POST time points were calculated for each participant based on their individual TTE. Data were analyzed using repeated measures ANOVA. Results:There was a significant interaction for heart rate (F=6.180, p=0.024, h2=0.382). Heart rate increased from PRE to MID to POST for both MT and HT (p<0.001). In addition, heart rate was significantly greater in HT (159.82 +17.47) compared to MT (146.09 +20.70) at PRE (p=0.031). There was also a significant interaction for VO2(F=4.312, p=0.030, h2=0.324). VO2also increased from PRE to MID to POST for both MT and HT (p< 0.05). In addition, VO2was significantly greater in MT (3.30 +0.52) vs HT (3.05 +0.33) at POST (p=0.025). There was a significant difference in TTE between conditions (p=0.008) with MT (303.00 +121.20 seconds) being significantly longer than HT (174.00 +54.41 seconds). Conclusions:This data suggests that the participants were able to perform at a higher intensity and for a longer duration in MT compared to HT.