Acute Cardiopulmonary Response to Interval and Continuous Exercise in Older Adults: A Randomized Crossover Study

The purpose of this study was to compare the cardiopulmonary response with different exercise protocols in healthy older adults. Subjects (n = 30; 15 women, age: 69.6 +/- 6.2 years) completed an exercise test (MAX) on a cycle ergometer to determine maximal oxygen consumption (<(V) over dot>O(2)max) and peak power output (PPO). Exercise sessions were randomized: high-intensity interval exercise (HIIE, 1 minute 90% PPO followed by 1 minute 10% PPO, x10), moderate-intensity continuous exercise (MOD, 20 minutes at 50% PPO), and sprint-interval exercise (SPRT, 20 seconds "all-out" sprints followed by 2 minutes at 50 W, x3). <(V) over dot>O(2)max was highest during MAX in men (MAX: 28.2 +/- 6.3; MOD: 22.6 +/- 4.5; HIIE: 26.7 +/- 5.7; SPRT: 26.0 +/- 4.3; F(2.1) = 28.6, rho = 0.0001, eta(2)(rho) = 0.67), whereas similar peaks were observed between HIIE, SPRT, and MAX in women (MAX: 21.9 +/- 6.1; MOD: 18.9 +/- 4.5; HIIE: 21.6 +/- 5.3; SPRT: 21.7 +/- 3.9; F(2.2) = 10.2, rho = 0.0001, eta(2)(rho) = 0.42). The peak heart rate (b.min(-1)) was similar across all exercise sessions in both men (MAX: 148.1 +/- 17.1; MOD: 132.6 +/- 21.8; HIIE: 144.9 +/- 16.6; SPRT: 148.6 +/- 14.2; F(1.9) = 59.1, rho = 50.001, eta(2 )(rho)= 50.41) and women (MAX: 148.1 +/- 13.1; MOD: 136.3 +/- 18.2; HIIE: 147.0 +/- 16.4; SPRT: 148.5 +/- 18.0; F(2.0) = 5.3, rho = 0.011, eta(2 )(rho)= 50.27). The %<(V) over dot>O-2 at which sessions were performed varied significantly across individual subjects. In conclusion, older women work at near maximal <(V) over dot>O-2 when performing HIIE and SPRT; this has implications for exercise testing and prescription protocols in older adults.