Many people fixate on the number of exercise calories they burn. New research, sponsored by Les Mills International, shows that even when two group fitness activities (indoor cycling and a resistance workout) were matched for duration and caloric expenditure, they did not have equivalent metabolic effects—which could influence long-term training results. Lead study author Nigel Harris, PhD, said, “The type of exercise used to burn those calories . . . impacts the long-term positive effects that exercise has on the body.”

Twelve healthy, active female participants completed the two workouts on separate days. Researchers then measured the women’s physiological and hormonal responses using blood samples taken before the sessions, immediately afterward and 45 minutes later. Data analysis showed that, at the 45-minute mark, human growth hormone and blood lactate levels were significantly higher after group resistance training than they were after cycling. Study authors noted that human growth hormone stimulates protein synthesis and bone mineralization, among other things.

The study is open access and is available in the Journal of Science and Medicine in Sport (2017; doi:10.1016/j.sams.2018.02.010).