Effect of Morning v. Evening Training on Sweat Rate and Sweat Sodium of Competitive Ultimate Athletes

Abstract

Hydration is essential to any individual’s well-being, especially for athletes and those who are physically active. A significant amount of water is lost through sweating, which can be detrimental to sports performance. Ultimate frisbee or Ultimate, is a high-intensity intermittent sport with significant demands on cardiovascular and muscular endurance and is often played outdoors. This study aimed to explore the effects of time-of-day specific training on the sweat rate and sweat sodium concentration of competitive ultimate athletes in a tropical setting. Data was collected from 14 competitive ultimate athletes during one morning (AM) and one evening (PM) training session during the competitive season in the hot months of April to early June. Bulb globe temperature (WBGT) recorded during AM sessions was 31.69 ± 2.7°C, air temperature (TA) of 38.45 ± 3.0°C, and relative humidity (RH) of 38.7 ± 8.3%. For PM training sessions, the WBGT was measured at 25.25 ± 1.6°C, TA at 27.89 ± 1.4°C, and RH at 74.55 ± 10%. No significant difference was seen between the average whole-body sweat rate (WBSR) of competitive ultimate players in the AM and the PM sessions. On the other hand, mean whole-body sweat sodium concentration (WBS [Na+]) was observed to be significantly different for AM and PM training sessions. This study underscored the significance of developing personalized hydration strategies that consider both environmental conditions and the specific type of exercise to be undertaken.