The Relationship Between Overweight and Heart Rate in Hot and Very Hot Weather Under Controlled Conditions

Abstract

Background: There is a high prevalence of overweight and obesity among adults. Obesity and overweight might be a risk factor affecting heat generation and excretion. Objectives: This study examines the relationship between overweight and heart rate in hot and very hot weather under experimental conditions. Patients and Methods: This experimental study was conducted with a sample of 35 participants with normal weight and 35 participants who were overweight in a climatic chamber. Each participant was asked to rest in a lying position on a bed for 30 minutes and the participants' basic heart rate was recorded. Each participant performed 60-min light exercise (2.8 kmph) on a treadmill) while exposed to very hot and moderate humid climatic conditions. In the other phase, participants were asked to rest for 30 min and then performed moderate exercise (4.8 kmph on a treadmill) for 60 minutes while exposed to hot and moderate humid climatic conditions. Heart rate was measured every 2 minutes. Results: The mean and standard deviation of the heart rate in the hot climatic condition and moderate exercise were 103.84 (334) for normal weight subjects and 108.67(3.27) for overweight subjects. The mean and standard deviation of the heart rate in a very hot climatic condition and light exercise were 96.13 (2.34) for those with normal weight and 105.84 (3.71) for those who were overweight. Heart rate significantly differed between the two groups in both climatic conditions (P<0.001). Conclusions: The mean heart rate was higher in participants who were overweight than those with normal weight.