Oxygen consumption during repeated inertial load exercise sprints with differing recovery durations in older adults

As the generation termed the “baby boomers” continue to age the proportion of older adults in the population continues to climb increasing the demand for viable ways to improve “health span” by exercise to improve cardiovascular and musculoskeletal health and reduce medical costs due to unhealthy aging. Inertial load cycle ergometer (ILE) sprints lasting 4s each, have been shown to provide consistent maximum power outputs in individuals of all ages. This study examined the effect of 60s, 45s, and 30s recoveries between sprints, performed for a total of 15 minutes, on oxygen consumption and heart rate. Six subjects aged 61 ± 2.6 yrs and VO₂ [subscript peaks] of 2.91 ± 0.51 L/min completed three separate trials of 15 ILE sprints with 60s recovery, 20 ILE sprints with 45s recovery, and 30 ILE sprints with 30s recovery during weeks 1, 4, and 8 respectively of a progressive eight-week repeated ILE training program that consisted of three training sessions per week. During each trial 6 of the ILE sprints included VO₂ collection using breath by breath, average of total power, HR, and RPE were recorded across similar time points during each trial. Percentage of VO₂ [subscript peak] was measured at 38.22 ± 2.17, 61.3 ± 6.50, and 59.14 ± 5.31during the trials of 60s, 45s, and 30s recoveries between sprints respectively (60s recovery vs. 45s recovery p=0.0138; 60s recovery vs. 30s recovery p=0.0251). %HR maximal was not statistically different between trials (p=0.133). Within the population there was a correlation between average power maximums and VO₂ (r=.73; p=0.0006), VO₂ and estimated stroke volume (SVEst.) (r=0.94; p <0.0001), and rating of perceived exertion (RPE) and %HR maximal (r=0.24; p<0.05) during each ILE sprint trial. In conclusion, ILE sprints may elicit the same maximal power outputs with 60s, 45s, and 30s recoveries with comparable cardiovascular stress following 45s and 30s recovery periods.