You have probably been told to stay active as you get older, and not to overdo it. A gentle walk, a steady bike ride, maybe some light weights. The advice feels safe. But the gentler option may carry a quiet downside.
In a six-month trial of 123 healthy adults with an average age of 72, only high-intensity interval training trimmed body fat while fully preserving lean muscle. Moderate-intensity exercise burned fat too, but came with a small drop in muscle.
The results come from researchers at the University of the Sunshine Coast and the University of Queensland in Australia, published in the journal Maturitas.
That matters because muscle gradually fades with age, and the pace of loss speeds up after 60. Muscle is what helps you stand up from a chair, carry groceries, and catch yourself from a stumble.
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What the researchers actually did
The team recruited 123 healthy adults from the Greater Brisbane region in Australia, with an average age of 72. Participants were randomly placed into one of three supervised gym programs.
One group did high-intensity interval training. A second did moderate-intensity continuous exercise. The third did low-intensity sessions. All three trained three times a week for six months, with each session lasting about 45 minutes.
Both the high-intensity and moderate groups lost body fat over the six months. Only the HIIT group held on to all of their lean muscle. The moderate group lost a small amount of muscle along with the fat.
Why losing muscle after 70 is such a concern
Muscle loss has a medical name, sarcopenia. It is the age-related decline in muscle mass and strength that is linked to falls, disability, and a loss of independence.
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Research in the Journal of Cachexia, Sarcopenia and Muscle found that losing either muscle mass or muscle function alone raises an older adult's risk of losing physical independence.
For an adult over 70, keeping muscle is not about looking toned. It is about walking without wobbling, climbing stairs without stopping, and getting back up if a fall happens. A workout that trims fat but shaves off muscle is a mixed result at best.
What HIIT looks like for someone over 70
HIIT does not mean sprinting until you collapse. The study team described it as repeated short bursts of hard exercise, where breathing is heavy and conversation is difficult, alternated with easier recovery periods.
In practice, that can mean a few minutes of warm-up, then short rounds of fast cycling, uphill walking or similar effort, broken up by slower stretches of the same movement. The study ran these sessions in a supervised gym under trained instructors.
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"HIIT likely works better because it puts more stress on the muscles," study co-author Mia Schaumberg told Medical News Today. That stress gives "the body a stronger signal to keep muscle tissue rather than lose it."
The study tested only three supervised gym sessions a week. Whether the same muscle-preserving effect holds for shorter sessions or home workouts has not yet been shown.
Older adults with heart disease, joint problems or other conditions should talk to a doctor before adding hard intervals to a routine.
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This article is made and published by Aksel Kryhlmand, who may have used AI in the preparation.