Sweat Rate Study

Introduction

More marathon foot races are currently being organised in cities all over the world in which the majority of the participants are non-elite or recreational runners whose major reason for participation is either to improve their physical fitness or purely for fun as part of a social experience. Although proper hydration is important to maintain performance and prevent impairment during a marathon, the volume of fluid required to offset the amount of fluid lost by sweating (sweat rate) while running varies from individual to individual. This in turn depends on the physical built of the runner, the amount and duration of physical activity and the environmental conditions.

A recent study on practices and perceptions regarding hydration among non-elite marathon runners by O’Neal et al reported that almost 70% of runners experienced at least one incident resulting in performance decrement which they attributed to “dehydration” (although other explanations cannot be excluded). However, only 20% of participants in this study reported monitoring of their hydration status either by urine colour or by measuring change in body weight. Calculating the sweat rate by measuring change in body weight is one of the most common and reliable methods to determine fluid loss in runners. Although the sweat rates have been previously reported, most of these were from studies conducted on elite athletes from Western/European populations. To the best of our knowledge, such data are lacking for non-elite, recreational runners, especially from a developing country like India where hot and humid weather conditions are the norm.

Hence the purpose of our study was to determine sweat rates among non-elite, recreational runners under hot and humid environmental conditions and to determine factors affecting those sweat rates. These data will help to develop hydration strategies for these runners in the future.