Mathew Sloan, the executive editor of Harvard Men’s Heath Watch, summarizes a study that discovered a lasting benefit attributable to high-intensity interval training. 

Engaging in regular exercise is linked to multiple health benefits, including maintaining cognitive abilities and perhaps reducing the risk of dementia. 

Results from a study published online in July 2024 by Aging and Disease suggest high-intensity interval training (HIIT) may be better for brain health that other, less vigorous routines. HIIT workouts consist of repeated cycles of short bursts of high-intensity exercise followed by brief “recovery” periods of lower intensity movement. 

In the study, researchers enrolled 151 healthy adults, ages 65 to 86, in a six-month exercise program. Participants underwent a battery of tests to assess function in the hippocampus — the brain area associated with learning and memory. 

Study participants were randomly assigned to do one of three half-hour exercise routines: balance and stretching; brisk walking on a treadmill; or four HIIT cycles on a treadmill. Each HIIT cycle consisted of four minutes at 85% to 95% of a person’s maximum heart rate, followed by three minutes of recovery.      

Everyone did approximately 30-minute workouts three days a week for about six months, for a total of 72 sessions. On repeat testing, only the HIIT exercisers showed positive changes in hippocampus functioning compared to their initial evaluation. At a follow-up evaluation five years later, the researchers found that people in the HIIT group retained their improved cognitive function, even if they were no longer doing HIIT.