High-Intensity Exercise Also Reduced Abdominal Fat
Beyond the preservation of muscle, the study highlighted another major health benefit of more vigorous exercise: the reduction of visceral adipose tissue, commonly known as abdominal fat. Unlike subcutaneous fat, which sits just beneath the skin, visceral fat is stored deep within the abdominal cavity, where it wraps around vital organs like the liver, pancreas, and intestines.
The presence of excessive visceral fat is a known risk factor for a host of metabolic and cardiovascular issues. It is highly active tissue that releases hormones and inflammatory substances, which can lead to insulin resistance, type 2 diabetes, and heart disease.
"Both high and moderate intensities improved the composition of weight carried around the middle," Dr. Rose noted, though she added that further analysis is required to fully understand the results from the low-intensity group.
The fact that HIIT was able to target this dangerous form of fat while simultaneously protecting muscle mass makes it an attractive option for those looking to mitigate the risks of chronic disease. As people age, the way their body stores fat often shifts toward the midsection, making targeted interventions more important than ever. Dr. Rose emphasized that these findings are vital because body composition—rather than just the number on the scale—is a primary driver of health outcomes and the progression of age-related illnesses.
Why HIIT May Help Aging Muscles Stay Strong
The biological "why" behind HIIT’s effectiveness lies in the stress it places on the musculoskeletal and cardiovascular systems. Unlike steady-state exercise, such as walking at a constant pace, HIIT requires the body to adapt to rapid changes in demand.
Associate Professor of Physiology and study co-author Mia Schaumberg explained the mechanics of the training used in the trial. "High-intensity training in this study involved repeated short bursts, or intervals, of very hard exercise—where breathing is heavy and conversation is difficult—alternated with easier recovery periods," she said.
This "all-out" effort, even if it only lasts for a minute or less, creates a physiological stimulus that moderate exercise cannot replicate. "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," Schaumberg added.
From an evolutionary perspective, the body is an efficient machine that seeks to shed tissues it deems unnecessary. If an exercise routine is moderate and predictable, the body may decide it does not need to maintain a high level of muscle mass to complete the task. However, when faced with the "emergency" demand of high-intensity intervals, the body prioritizes the retention of muscle fibers to meet that challenge.
This preservation is the frontline defense against sarcopenia. By maintaining a higher baseline of muscle through their 60s, 70s, and 80s, seniors can significantly extend their "healthspan"—the period of life spent in good health, free from the limitations of frailty.
When the University of the Sunshine Coast publicized these findings in early 2026, Professor Schaumberg noted that the timing was particularly relevant for those looking to reset their health habits. "With the festive season now behind most of us and New Year’s resolutions in full swing, this research can help inform people’s plans for healthy aging in 2026," she said.
