Physical activity in hot and humid environments can have adverse effects on all populations. RPE can effectively measure impending fatigue during exercise testing and can be utilized for exercise prescription. Numerous studies have looked at how heat stress can affect RPE and physiological factors during prolonged bouts of exercise. For example, physiological stress, exercise duration, environmental conditions, and perceptual responses have all been shown to positively correlate with RPE. Examination of the effect of environmental conditions on RPE has largely involved the use of heat, and it has been shown that physical activity in a hot environment elevates both physiological and perceptual responses.