If you’ve been told that “any exercise is good exercise” as you age, new research suggests the intensity may matter more than most people realize. A study out of Australia found that high-intensity interval training (HIIT) helped older adults reduce body fat while preserving lean muscle — a critical advantage in healthy aging.
That’s important because after 60, many people don’t just gain fat more easily — they also lose muscle more quickly, which can accelerate weakness, falls, metabolic slowdown, and loss of independence.
Researchers followed more than 120 healthy older adults (average age 72) who completed supervised exercise three times per week for six months. Participants were assigned to either HIIT (short bursts of very hard effort with recovery periods), moderate-intensity training, or low-intensity exercise.
All groups saw modest fat loss, but only the HIIT group maintained lean muscle mass over time. In the moderate-intensity group, researchers saw small declines in muscle — suggesting that while steady exercise can help with fat reduction, it may not provide a strong enough signal to protect muscle tissue in older age.
The takeaway is simple: in aging bodies, preserving muscle isn’t optional — it’s protective. Muscle helps stabilize blood sugar, supports balance, strengthens bones, and keeps metabolism resilient. HIIT may work better because it stresses the muscles more, encouraging the body to hold onto lean tissue rather than break it down.
That said, HIIT isn’t for everyone — especially if you have heart issues, joint pain or mobility limitations — but even adding small bursts of higher intensity (like brief faster walking intervals) may offer outsized benefits. The goal isn’t to “train like an athlete,” but to keep your body strong enough to age with power, not fragility.
SOURCE:
Medical News Today, February 2, 2026