| Research Abstract |
We assessed the effects of aerobic/ resistance training on thermoregulatory responses in older men and analyzed the results in relation with changes in peak aerobic capacity ( VO_<2, peak> ) and blood volume ( BV ). Twenty male subjects ( age, 64±1yr; VO_<2, peak>, 32.8±1.2ml・kg^<-1>・min^<-1>, mean±SE ) were divided into 3 training regimens for 18 weeks; control ( C, n=7 ), aerobic training ( AT, n=8 ), and resistance training ( RT, n=8 ). Subjects in C were allowed to perform a walking of 〜10,000 steps a day, 6〜7days a week. Subjects in AT exercised on a cycle ergometer at 50-75 % VO_<2, peak> for 60 min a day, 3 days a week, besides the walking. Subjects in RT performed a resistance exercise including knee extension and flexion at 60-80 % of 1RM, 2-3 sets of 8 repetitions a day, 3 days a week, besides the walking. After training, VO_<2, peak> increased by 3.1±4.6% in C ( n.s. ), 14.3±2.4% in A ( p<0.01 ), and 8.4±2.9 % in R( p<0.05 ), but BV remained unchanged in all trials. Also, the esophageal temperature ( T_<es> ) thresholds for forearm skin vasodilation and sweating, determined during 30-min exercise of 60 % VO_<2, peak> at 30℃, increased in AT ( p<0.05 ) and RT ( p<0.05 ) but not in C ( P>0.0x ). In contrast, the slopes of forearm skin vascular conductance/ T_<es> and sweat rate/ T_<es>, remained unchanged in all trials, but increased in subjects with increased BV irrespective of trials. Thus, aerobic/ resistance training in older men increased VO_<2, peak> and lowered T_<es> threshold for forearm skin vasodilation and sweating, but did not increase BV. Further, the sensitivity of increase in skin vasodilation and sweating at a given increase in T_<es> was more associated with BV than VO_<2, peak>.
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