Thermoregulation of Pregnant Women During Aerobic Exercise on Land and in the Water

Abstract

Seven women in their 25th week of pregnancy exercised for 20 minutes on a cycle ergometerat 70% of their maximal heart rate on land and in the water (30°C) to compare thermoregulatory responses. Rectal temperatures increased 0.5 ± 0.1°C during the land trial and only 0.2 ± 0.1°C during the water trial (p <0.05). Mean body temperature rose 0.6 ± 0.2°C during the land trial, but declined -0.3 ± 0.1°C during the water trials (p <0.05). Land exercise caused greater heat storage and sweat loss. The results suggest that normal pregnant women can maintain thermal balance during 20 minutes of exercise at 70% maximal heart rate, whether on land or in the water. Thus, for normal, average fit, pregnant women who wish to participate in a moderate exercise program, heat stress is probably not a major concern.