Older adults may benefit most from HIIT exercise, study suggests

Maintaining both muscle mass and a healthy body fat percentage is a key component of healthy aging. Recent research suggests that the type of exercise may play a significant role in achieving this balance. A new study from Australia indicates that high-intensity interval training, or HIIT, may be particularly effective for older adults seeking to reduce body fat while preserving muscle.

Understanding Body Composition

Body composition, which refers to the proportions of lean body mass and body fat, offers a more precise measure of health and fitness than body mass index (BMI). Healthcare professionals recommend regular physical activity for older adults to promote health and manage changes in body composition. However, until recently, limited research existed on the optimal exercise types for improving body composition in this age group.

The Australian Study

Researchers at the University of the Sunshine Coast investigated the effects of different exercise intensities on body composition in over 120 healthy older adults from the Greater Brisbane region. Participants, with an average age of 72 and a BMI of 26 kg/m2 – categorized as normal for those over 65 – were divided into three groups and participated in supervised exercise programmes three times a week for six months.

Exercise Groups

HIIT: Short bursts of very vigorous activity alternated with recovery periods.
Moderate-intensity training: Continuous exercise at a steady, moderate effort.
Low-intensity training: Gentler sessions designed for ease and sustainability.

Did You Know? The study participants had an average BMI of 26 kg/m2, which researchers categorized as normal for people aged over 65.

All three groups experienced modest reductions in body fat. However, only the HIIT group successfully maintained their lean muscle mass throughout the six-month study period. The moderate-intensity group showed slight muscle declines, while the effect of low-intensity training was less clear.

What Makes HIIT Different?

HIIT involves alternating short bursts of vigorous activity – where breathing is heavy and conversation is difficult – with easier recovery periods. Researchers believe that HIIT’s effectiveness stems from the greater stress it places on muscles, signaling the body to retain muscle tissue rather than lose it. This type of training forces the body to work anaerobically, breaking down glucose for energy without using oxygen.

Expert Insight: This research adds to the growing body of evidence suggesting that exercise intensity may be a more critical factor in healthy aging than simply the quantity of physical activity.

Study lead author Grace Rose, PhD, of the University of the Sunshine Coast, stated, “We found that high, medium and low intensity exercises all led to modest fat loss but only HIIT retained lean muscle.” Study co-author Mia Schaumberg, PhD, added, “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.”

Looking Ahead

While all exercise offers benefits, these findings suggest that incorporating high-intensity intervals into fitness routines could be a valuable strategy for older adults aiming to reduce fat mass without sacrificing muscle. However, HIIT may not be suitable for everyone, particularly those with existing health conditions or mobility limitations. Further research is needed to understand the long-term effects of different exercise types on diverse aging populations.

Frequently Asked Questions

What is body composition?

Body composition describes the relative proportions of lean body mass (muscles, bones, skin, organs, and water) and body fat mass. It can offer a more precise measure of health and fitness than body mass index (BMI).

What type of exercise was most effective in the study?

High-intensity interval training (HIIT) was found to be the most effective exercise for reducing body fat while maintaining lean muscle mass in older adults.

Is HIIT safe for all older adults?

The study generally involved healthy older adults, so results may differ for those with certain health conditions or mobility limitations. Anyone considering a new or more intense exercise regimen should consult a healthcare professional or qualified trainer.

As research continues to refine our understanding of exercise and aging, how might these findings influence personalized fitness recommendations for older adults in the future?