A six-month study of more than 120 healthy adults in their 70s found that high-intensity interval training (HIIT) reduced body fat while maintaining lean muscle. Moderate- and low-intensity programs also produced modest fat loss, but moderate training was linked to a small decline in lean muscle.
Researchers from the University of the Sunshine Coast (UniSC) compared exercise intensities in more than 120 healthy older adults from Australia’s Greater Brisbane region.
Participants completed three gym-based, supervised exercise sessions per week over six months. The group’s average age was 72, and average body mass index (BMI) was 26 kg/m².
The study found that high-, moderate-, and low-intensity exercise programs all produced modest fat loss. But only the HIIT program preserved lean muscle, according to lead author Dr. Grace Rose.
"We found that high, medium and low intensity exercises all led to modest fat loss but only HIIT retained lean muscle," Rose said.
Rose said moderate-intensity training reduced fat mass but came with a tradeoff.
"While moderate training reduced fat mass, it also caused a small decline in lean muscle," she said.
UniSC Associate Professor of Physiology and co-author Mia Schaumberg said HIIT may protect muscle because it places greater stress on muscle tissue.
"HIIT likely works better because it puts more stress on the muscles, giving the body a stronger signal to keep muscle tissue rather than lose it."
The findings were published in the journal Maturitas, and the project involved UniSC researchers as well as collaborators from The University of Queensland.
