HIIT May Help Older Adults Lose Fat While Preserving Muscle Mass

What's new

New research suggests that high-intensity interval training (HIIT) could be particularly beneficial for older adults aiming to reduce body fat while simultaneously maintaining muscle mass. A study involving over 120 adults in their 70s found that while various exercise intensities led to some fat loss, only HIIT successfully preserved lean muscle mass [1]. This finding is significant because preserving muscle is crucial for health as people age.

The study, conducted by researchers at the University of the Sunshine Coast, compared the effects of high, moderate, and low-intensity exercise on body composition over a six-month period. Participants engaged in three supervised gym sessions per week. All groups experienced some reduction in body fat. However, the moderate-intensity group, despite losing fat, also saw a slight decrease in lean muscle. The low-intensity group's results on body composition require further analysis. These results highlight a unique benefit of HIIT for older populations [1].

The science behind it

The study enrolled more than 120 healthy older adults, with an average age of 72 and a body mass index (BMI) of 26 kg/m2, which is considered within the normal range for adults over 65. Participants were divided into groups performing different exercise intensities: high-intensity interval training (HIIT), moderate-intensity training, and low-intensity training. Each group completed three supervised exercise sessions per week for six months [1].

HIIT, in this context, involved short bursts of very demanding exercise where breathing was heavy and conversation difficult, alternated with periods of easier recovery. Researchers hypothesize that this type of training places greater stress on muscles, sending a stronger signal to the body to retain muscle tissue rather than break it down. This mechanism could explain why HIIT was uniquely effective in preserving lean muscle mass compared to other intensities [1].

Body composition, which refers to the proportion of fat and lean mass in the body, is a critical health indicator, especially in older adults. Changes in body composition, such as increased fat mass and decreased muscle mass (sarcopenia), are linked to the development and progression of many chronic diseases later in life. Therefore, an exercise regimen that supports fat loss while protecting muscle mass offers substantial health benefits for aging individuals [1].

What it means in practice

For older adults looking to improve their body composition, these findings suggest that incorporating HIIT into their fitness routine could be a highly effective strategy. While any form of exercise can contribute to fat loss, HIIT appears to offer the added benefit of muscle preservation, which is vital for maintaining strength, mobility, and overall health in later years [1].

Before starting any new exercise program, especially one involving high intensity, older adults should consult with a healthcare professional or a certified exercise physiologist. This ensures that the chosen program is appropriate for their individual health status and fitness level. Supervised sessions, as conducted in the study, can also help ensure proper form and safety [1].

HIIT typically involves alternating short periods of intense anaerobic exercise with less intense recovery periods. This can be adapted to various forms of exercise, such as cycling, brisk walking, or bodyweight exercises, making it accessible to many individuals. The key is to reach a high level of exertion during the intense intervals, where speaking becomes difficult [1].

Caveats

While the study provides promising insights, it's important to consider some limitations. The research focused on healthy older adults, and the findings may not be directly applicable to individuals with pre-existing health conditions or lower baseline fitness levels. The study was also conducted over six months, and the long-term effects of HIIT on body composition in older adults would require further investigation [1].

Additionally, the study was supervised, which might not always be feasible for individuals exercising independently. The specific types of exercises used within the HIIT protocol were not detailed, which could influence generalizability. Further research could explore optimal HIIT protocols, including frequency, duration, and specific exercises, for diverse older adult populations [1].

Source: [1] https://www.sciencedaily.com/releases/2026/06/260622014305.htm