EFFECTS OF VARYING LEVELS OF HYPOHYDRATION ON RATINGS OF PERCEIVED EXERTION

To investigate the effects of varying levels of hypohydration on ratin gs of perceived exertion (RPE) during moderate and heavy submaximal ex ercise, and at the lactate threshold (LT) and ventilatory threshold (V T), 9 male subjects cycled under states of euhydration (EU), moderate hypohydration (MH), and severe hypohydration (SH). The desired level o f hypohydration was achieved over a 36-hr period by having subjects cy cle at 50% VO2max in a 38-degrees-C environment on two occasions while controlling fluid intake and diet. During submaximal exercise, oxygen uptake, ventilation, heart rate, blood lactate, and RPE were not sign ificantly different among treatments. Hypohydration did not significan tly alter LT or VT, or perceptual responses at LT or VT. It is conclud ed that hypohydration of up to 5.6% caused by fluid manipulation and e xercise in the heat over a 36-hr period does not alter RPE or the lact ate or ventilatory threshold, nor RPE at the lactate and ventilatory t hresholds measured during moderate and heavy submaximal cycling in a n eutral (22-degrees-C) environment.