HIIT Preserves Muscle While Reducing Fat in Older Adults, Trial Finds
A six-month trial with 123 healthy older adults found that all exercise intensities produced modest fat loss, but only high-intensity interval training preserved lean muscle. HIIT also improved body composition around the waist, while moderate-intensity exercise was associated with a small loss of lean tissue. The University of the Sunshine Coast team published the results in Maturitas.
The trial involved 123 healthy older adults in Greater Brisbane, average age 72 and BMI about 26, which researchers considered normal for over-65s. They attended three supervised 45-minute gym sessions weekly for six months, assigned to high-, moderate-, or low-intensity groups. Body composition was scanned at baseline, three months, and six months.
Both high and moderate intensities cut fat mass more than the low-intensity comparison, but only HIIT avoided a decline in lean tissue. Scans measured lean mass, which includes muscle along with other tissues and water, so results don't directly indicate strength changes.
Older adults hoping to stay independent may find this useful, since muscle supports stair climbing, standing, and balance. If HIIT preserves lean tissue while trimming fat, it could appeal to people and clinicians planning exercise programs — though supervised sessions three times weekly may not suit everyone. The findings might also nudge fitness providers to offer age-appropriate interval options. Because scans measured lean tissue rather than strength, real-world benefits remain uncertain.