This Workout Style Could Help Preserve Muscle as You Age

All movement counts, especially when you do it safely and with good form. But depending on your goal, whether that is moving more, building strength, improving fitness, or reducing body fat, some types of exercise may offer extra benefits.

New research suggests one style of training may have an advantage when it comes to reducing body fat while preserving valuable muscle mass, especially in older adults.

A recent study published in Maturitas looked at which type of exercise most effectively reduced body fat without reducing muscle mass. The study included 123 older adults with an average age of 72 and no pre-existing medical conditions.

Researchers split participants into three groups. One group followed a low-impact exercise program, one followed a moderate-intensity program and one followed a high-intensity interval training program, also known as HIIT.

Each group completed three supervised 45-minute exercise sessions a week for six months. Researchers then analysed body composition scans taken at the beginning and end of the study.

The results were interesting. Both HIIT and moderate-intensity exercise helped reduce body fat. But the moderate-intensity program was also linked with a small decline in muscle mass. HIIT was the only approach that reduced fat while helping maintain muscle.

Before you overhaul your current routine, it is worth understanding what that means in real life. Fitness experts explain below.

Why might HIIT exercise reduce fat without reducing muscle?

First, what is HIIT?

“High-intensity interval training is a type of exercise training that incorporates high-intensity cardiovascular intervals with active recovery built in between,” explains a board-certified clinical specialist in orthopaedic physical therapy. Karena Wu. “This exercise training allows the body to recover before performing activities that require a lot of energy expenditure.”

In this study, the HIIT sessions were performed on a treadmill. But HIIT can also include other whole-body exercises, including cycling, rowing, resistance exercises, or bodyweight moves. The defining feature is the interval structure: short bursts of higher effort followed by active recovery.

That structure may be part of why HIIT helps preserve muscle.

“Interval training reinforces active recovery for the body to optimize peak performance in both strength training and fat burning. The extremely high-intensity exercises will recruit more muscle fibers to help with muscle mass maintenance,” Wu explains.

In simple terms, HIIT asks the muscles to work hard, then gives them time to recover before the next effort. That repeated challenge may help the body use energy while still giving muscles a strong reason to stay active and engaged.

Corrective exercise specialist and chiropractor Anna Di says the idea is not new in fitness circles.

“Interestingly, this idea of using higher-intensity cardio while trying to preserve muscle isn’t new,” Di says. “It’s one of the reasons many competitive bodybuilders choose HIIT during fat loss phases because they’re trying to maintain as much lean muscle as possible while reducing body fat. They’re obviously training for a very different goal than the average person, but the concept is similar.”

What makes this study useful, Di says, is that it looked at relatively healthy older adults. That makes the findings more relevant for people who are not athletes, but still want to protect muscle as they age.

That matters because muscle is not only about strength or appearance. It supports balance, metabolism, mobility, blood sugar control and the ability to keep doing everyday tasks, from climbing stairs to carrying groceries.

Does HIIT exercise have other benefits?

Reducing body fat and preserving muscle are not the only reasons HIIT gets attention.

“HIIT has been shown in many studies to improve cardiovascular fitness, blood sugar regulation, and overall conditioning,” Di explains.

That said, higher-intensity exercise is not the right starting point for everyone. It can place more demand on the heart, joints, muscles and balance than gentler exercise. That is why Di cautions people with underlying health conditions, balance issues, or little recent exercise experience against jumping in without medical advice.

“Individuals with cardiovascular conditions that are not well controlled, poor core/pelvic weakness, or significant joint problems should avoid HIIT due to the high-impact forces,” Wu adds. “People with elevated stress and poor management should not participate as HIIT can spike cortisol levels.”

If you are new to exercise, returning after injury, managing high blood pressure, living with heart disease, or dealing with joint pain, speak with your GP, physiotherapist, or accredited exercise professional before trying HIIT.

What does this mean for you?

If you are in good health and have cleared any concerns with a healthcare professional, HIIT may be worth adding to your routine, especially as you get older.

“Maintaining muscle mass becomes increasingly important as we age because muscles are what give us strength, mobility, and balance,” Di explains. “Muscle also plays an important role in regulating blood sugar.”

Muscle also supports bone health.

“Something many people don’t realize is that muscles are also what pull on our bones,” Di says. “That mechanical stress is one of the signals that helps bones stay thicker and stronger over time, which is especially important as we get older and for women after menopause when the risk of osteoporosis increases.”

That does not mean low- or moderate-intensity exercise should be dismissed.

“The biggest takeaway is that both high-intensity and moderate-intensity exercises worked. Both reduced body fat, which is really the goal for many people,” Di says.

The low-impact exercises used in the study, such as stretching and toning classes, may also offer benefits that were not the main focus of the results, including flexibility, mobility and balance. Those are especially important for injury prevention, independence and confidence with movement.

“Yes, preserving muscle is important, but the amount of lean muscle loss in the moderate-intensity group was actually very small,” Di says. “For someone who’s older, new to exercise, or simply doesn’t enjoy high-intensity workouts, a regular walking program may still be an excellent option if it’s something they’ll consistently do.”

The best approach depends on your body, goals and current fitness level. For some people, HIIT may look like short treadmill intervals. For others, it may be brisk walking uphill, cycling with bursts of effort, or low-impact intervals on a stationary bike.

Intensity is personal. A power walk may feel challenging for one person, while a jog may feel moderate for someone else.

The bottom line

HIIT may have an advantage if your goal is to reduce body fat while preserving muscle. But the bigger message is not that everyone needs to train at maximum intensity.

All three exercise styles in the study had benefits. HIIT helped preserve muscle. Moderate-intensity exercise reduced body fat. Low-impact movement may support mobility, flexibility and balance.

The most useful exercise plan is the one you can do safely, consistently and realistically.

“In my opinion, consistency is much more important than chasing a small difference in muscle preservation if the alternative is not exercising at all,” Di explains.

Ultimately, “the best exercise is usually the one you’ll continue doing months and years from now.”