HIIT holds its own after 60, and may edge out steady cardio

High-intensity interval training has a solid record in younger people, where it delivers gains similar to or better than steady moderate cardio. Whether that holds after 60 has been far less certain, and it matters: older adults are often steered towards gentler continuous exercise by default, and if intervals work as well or better, that default deserves questioning. This meta-analysis set out to compare the two approaches head to head in older adults across fitness, body composition, vascular, metabolic and hormonal measures, cognitive function and quality of life.

The researchers searched six databases from inception to December 2023 for trials in adults aged 60 and over that compared high-intensity interval training with continuous moderate-intensity training. Twenty-nine trials covering 1,227 participants, with an average age of 65.4, were pooled. Effect sizes were calculated for each outcome, and the team also tested whether study quality and features of the training programmes changed the results.

For most outcomes the two approaches were equals: VO2max, peak workload, body fat percentage, blood sugar, and both systolic and diastolic blood pressure improved significantly and similarly with either. HIIT alone produced significant improvements in fat mass, waist circumference, testosterone and performance on a complex Stroop test of cognitive function, where moderate training did not reach significance. One further wrinkle favoured intervals: in the controlled trials, gains in VO2max appeared only after HIIT, not after moderate continuous training.

This extends what was already known in younger populations into the over-60s, where the evidence had been uncertain. It confirms that both training styles work for older adults on the headline health markers, while complicating the picture in HIIT's favour on body composition, cognition and, in the higher-quality trials, cardiorespiratory fitness. Open questions include which interval protocols work best for this age group and whether the cognitive and hormonal signals hold up in larger, longer trials.

If you are past 60, or planning for it, this is a reason to think intervals are not just for the young: they delivered everything steady cardio did in these pooled trials, plus a few things it did not. It is equally a reason not to abandon moderate continuous exercise, which matched HIIT on most measures, including blood pressure and blood sugar. The takeaway is that intensity appears to remain a usable tool at older ages, not something to be retired.