Abstract
We examined the effects of protein supplementation on body temperature regulatory capacity after aerobic training in older men. In the previous study, we suggested in older men that the sensitivities of cutaneous vasodilation and sweating at a given increase in esophageal temperature (Tes) did not increase after 18-wk aerobic training, which would be caused by unchanged plasma volume (PV) after training due to an attenuated increase in plasma total protein content (TPtot) (JAP, 93: 1630-1637, 2002). Recently, we found in older and younger men that the supplementation of protein & carbohydrate (CHO) (3.1 kcal/kg & 0.18 g protein/kg, respectively) immediately after a bout of exercise increased TPtot and PV measured at 23 h after the bout while that of placebo (0.5 kcal/kg, 0 g protein/kg) did not (FASEB J, 17: A943, 2003). In the present study, we examined the effects of protein & CHO supplementation during aerobic training on TPtot, PV, and also the sensitivities in older men. Fourteen older men (68±2 (SE) yrs) exercised at 60~70%Vo2peak, 60 min/day, 3 times/wk, for 8 wks with taking protein & CHO (S, n=7) or placebo (P, n=7) after exercise each day. After 8-wk training, TPtot and PV in S increased significantly but not in P. Also, the sensitivities of the rises in cutaneous vascular conductance (ΔCVC/ΔTes) and sweating (ΔSR/ΔTes) at a given rise in Tes increased significantly in S but not in P. Thus, the supplementation of protein & CHO enhanced the improvement of thermoregulatory capacity after endurance training by increasing PV in older men. [Jpn J Physiol 54 Suppl:S32 (2004)]
