The Best Exercise To Reduce Fat AND Retain Muscle In Later Life

Good news: you won’t even have to do a lot of it! In fact, just a few minutes daily, adding up to 15–20 minutes per week, is already a huge and beneficial improvement over not doing that.

See for example: How Useful Is “Exercise Snacking”, Really?

If you have the time/energy though, then yes, more is better, so it’s good to do more or work towards more if you can, and the study we’ll look at today did 135 minutes per week, so that’s can be a laudable benchmark to aim for if practical for you.

But, what is is it exactly that we need to do?

HIIT it!

This is about high-intensity interval training, or HIIT.

Researchers (Dr. Grace Rose et al.) did a randomized controlled trial involving 123 healthy adults with an average age of 72 years and an average body mass index (BMI) of 25.8 kg/m² to compare the effects of:

• High-intensity interval training (HIIT)
• Moderate-intensity exercise
• Low-intensity exercise

…on body composition over 6 months.

In each case, participants completed 3 supervised 45-minute treadmill-based exercise sessions each week, with exercise intensity prescribed individually using heart rate.

In fewest words: all exercise intensities produced modest fat loss, but only HIIT reduced fat while maintaining lean body mass*

^{*which is largely a stand-in term for muscle in practical terms, but saying lean body mass is technically more accurate since lean body mass also includes bones, water, organs, etc, but bone weight won’t meaningfully change in 6 months and water weight is not linked to exercise (and organ weight mostly follows water weight), so the muscle mass is the variable in question here.}

In a little more detail:

• HIIT significantly reduced fat mass, maintained fat-free mass (lean mass), improved body fat percentage, and reduced visceral (abdominal) fat
• Moderate-intensity exercise reduced fat mass and visceral fat but also caused small reductions in fat-free mass
• Low-intensity exercise produced modest fat loss, while muscular atrophy proceeded unabated.

Those other metrics that HIIT changes are worthy of note too, and we’ve written about those before, for example:

• How To Make Your Body Fat Heart-Healthier
• Losing Visceral Fat Cuts Diabetes Risk By 28% (Even If You Regain The Weight!)
• Visceral Belly Fat & How To Lose It

If you’d like to read the paper in full, here it is: Exercise intensity influences body composition: a 6-month comparison of high-intensity interval, moderate- and low-intensity training among healthy older adults

If you’d like to get started, a good place to begin is: How To Do HIIT (Without Wrecking Your Body) ← important, because the “high-intensity” part can cause problems for some people, if not undertaken attentively!

Want to learn more?

If cardio isn’t your thing and you prefer for your HIIT to be more resistance focused, then check out:

HIIT, But Make It HIRT

And if you’d like to delve much more deeply into the science of the broader topic, then you’ll surely love:

Science of HIIT – by Ingrid Clay

Lastly, if you’re comfortable that you know what you need to do, but knowing isn’t the problem, then consider:

I Will Make You Passionate About Exercise – by Bevan Eyles

What this isn’t: a “just do it!” motivational pep-talk.

What this is: a compassionate and thoughtful approach to help non-exercisers become regular exercisers, by looking at the real life factors of what holds people back (learning from his own early failures as a coach, by paying attention now to things he inadvertently neglected back then), both in the material/practical and in the psychological/emotional.

Enjoy!