Cardiorespiratory effects of expending 7000 and 14,000 kilocalories with varying energy expenditures per exercise session

The purpose of this l6 week study was to evaluate the effects of expending prescribed amounts of energy during a jogging program, and to see if these effects varied significantly when the energy expenditure each session was varied. Frequency and intensity of training were held constant. Specifically, the purposes of this study were: (1) to evaluate the effects of expending 7000 and l4,000 kcal of energy jogging at 80% of maximum heart rate three times a week, (2) to evaluate the differences in cardiorespiratory (c-R) improvement when expending a total of 700o kcal of energy with exercise sessions of 150 and 300 kcal expenditure, and (3) to evaluate the differences in C-R improvement when expending a total of l4,O00 kcal with exercise sessions of 300 and 450 kcal expenditure. Subjects were 38 college males (ages 18-24 years), 10 of whom served as a control group.

All experimental subjects were in one of three groups, each expending a prescribed amount of energy each session. The groups included a 150 kcal, 300 kcal, and 450 kcal group. Subjects were tested initially and after expending either 7000 or l4,000 kcal of energy. The 7ooo kcal test involved the testing of the control, 150 kcal, and 300 kcal groups. The 14,000 kcal test involved the testing of the control, 300 kcal, and 450 kcal groups. The test variables included resting heart rate, heart rate response to a fixed submaximal work rate, maximum heart rate, absolute maximun oxygen consumption, relative maximum oxygen consumption, body weight, and sum of skinfolds. Expending 150 kcal per workout for 16 weeks (total expenditure of approximately 700o kcal) significantly improved body composition, C-R efficiency, and maximal work capacity. Expending 450.kcal per workout for l0 weeks (total expenditure of approximately l4,000 kcal) significantly improved resting C-R function and maximal work capacity. It was found, also, that expending 150 kcal per workout for 16 weeks reduced body fat and improved C-R efficiency significantly greater than expending 300 kcal per workout for 8 weeks--the total energy expenditure being approximately 7000 kcal.

The improvements for the l50 kcal group were slightly exaggerated since three persons in that group ran more than what was prescribed. A separate analysis, run after deleting these three individuals, tended to point to the possibility of the 150 kcal group's improvements in maximal work capacity being not as great as they appeared. Also, this analysis revealed that, perhaps, the difference between the 150 kcal and 300 kcal groups at the 7000 kcal test was not significant.