Researchers comparing exercise regimens in adults 40-60 report that steady zone 2 sessions produced larger VO2 max gains than high-intensity intervals over 12 weeks.
Participants also reported better adherence and fewer joint complaints on the moderate protocol. Coaches say the finding does not eliminate HIIT but reframes it as a seasoning rather than a staple.
Home-fitness apps are already pivoting to longer, lower-intensity programming.
