Eight elderly but healthy male subjects (mean age 71.1 years) were evaluated for response of heart rate, systolic blood pressure and pulmonary ventilation during 6 minute exercise bouts at three levels of intensity on each of three types of exercise. One type of exercise, crawling, involved heavy rhythmic activity of both legs and arms; a second, walking, involved only heavy work of the legs; the third was cycling where leg work was heavy and moderate isometric contractions of the upper limb muscles occurred. Integrated electromyographic data were also taken during die exercise bouts in order to estimate quantitatively the relative loading of each of twelve groups of muscles and also the amount of total muscle mass activated (TMMA). It was our purpose to evaluate the contribution of relative loading and TMMA as determinants of the responses of heart rate, blood pressure, and ventilation to the different exercises in older men.
Multiple regression analysis of the data suggests that the systolic blood pressure response was largely determined by the relative muscle loading factor as has been suggested by the work of Lind and McNicol (12,13,14). Heart rate and pulmonary ventilation were better related to die TMMA.