One of the least pleasant things about getting older is the tendency to lose muscle. Research shows that starts happening by the age of 40, and by the time you hit 80 you can have lost as much as 50% of your skeletal muscle.

This decline is known as sarcopenia, and in addition to reducing strength, it can affect things like balance and the ability to get out of a chair later in life.

But losing muscle is not preordained.

You can maintain and even restore your muscle mass by practicing regular resistance training, also known as lifting weights. You can regain muscle in as little as four months, research in older adults has shown, but exercise orthodoxy has always held that to build muscle you must exercise with heavy weights—70% to 80% of the weight that you can lift just once.

The biggest problem with this is not the science but the motivation needed to follow such a grueling regimen regularly. You may find the prospect of going to a gym crowded with gorgeous young bodies off-putting, and the prospect of lifting such heavy weights can be daunting.

Is there an alternative? For the last year, I’ve been experimenting with a different kind of resistance training involving extremely light-weight workouts. It’s called blood flow restriction training (BFR), and extensive research has found it to be as effective as lifting heavy weights.

Here’s what you need to know.

The science behind the bands

Developed in Japan, which has the world’s largest population of seniors, BFR consists of putting inflatable bands a bit like a blood pressure cuff on your arms or legs. You use a pump to inflate the bands to a specific pressure determined by a number of factors, such as the circumference of the limb.

Example of BFR bands on the biceps
credit BStrong

With the bands in place, you do a very brief workout using extremely light weights — only 20% to 30% of what’s normally needed to gain muscle. For example, I’ve been getting a great upper arm workout using BFR and hand weights weighing just two and a half pounds.

A 2017 study by researchers in Sao Paulo involving 23 men and women between the ages of 51 and 70 found that while high-intensity weight training produced the best results, BFR training with weights weighing one-fourth as much produced substantial gains in both strength and muscle mass. BFR “constitutes an important surrogate approach to high-intensity resistance training as an effective training method to induce gains in muscle strength and mass in elderly,” wrote Carlos Ugrinowitsch and his colleagues.

Many of the benefits can be achieved simply by using the bands when you take a walk.

Other research by scientists at Deakins University in Australia has found that many of the benefits of using BFR can be achieved simply by using the bands when you take a walk. What’s more, they seem to help with problems like bone loss and arthritis.

Peter T. Lansbury, Jr., an associate professor of neurology at the Harvard Medical School and the chief scientific officer at drugmaker Lysosomal Therapeutics, told me he started using BFR bands five years ago when he developed inflammatory arthritis in his arms and couldn’t even lift a large carton of milk.

“It got me over a huge hump,” says Lansbury, who is now 60 years old. “My strength has really improved.”

What’s going on with BFR

How do the bands work? I spoke with Jim Stray-Gundersen, a sports medicine doctor in Park City, Utah, who works with the U.S. and Norwegian Olympic teams. He notes that the bands collapse the veins directly beneath them in your arms and legs, creating a kind of valve. When you exercise, that pushes the blood past the valve back toward the heart.

Like all resistance training, BFR carries risks if done improperly, mainly bruising or dizziness.

“The bands slow down the delivery of oxygen so that the working muscle cannot keep up, creating a bit of a crisis in the muscle,” Stray-Gundersen explains. “Our brains end up releasing a bunch of hormones, including growth hormone, that pours through the whole body, and that is the mechanism with which we are able to rapidly improve the size and strength of muscles, build new blood vessels, and actually strengthen bone.”

Like all resistance training, BFR carries risks if done improperly, mainly bruising or dizziness. In fact, Lansbury recommends getting some type of training in how to properly attach and inflate the bands as well as how to work out with them before trying them. (More on that below.)

Plus you need to know the difference between occlusion—blocking the blood flow to your arteries—and BFR, which should employ only moderate pressure that just slows the blood in your veins. Some bands on the market use occlusion, which could be dangerous and won’t give you the benefits associated with BFR.

How to get started

I’ve been working with two systems that use inflatable bladders in the bands to apply just a measured amount of pressure. The first, developed in Japan by a medical doctor named Yoshiaki Sato, is called KAATSU, which means “additional pressure” in Japanese.

The KAATSU system has been extensively studied in Japan. For example, a group of researchers at Tokyo Metropolitan University achieved between 7% and 10% increases in strength after two weeks of twice daily workouts.

At $2,100 for the KAATSU Nano I have been using, KAATSU is not cheap. One advantage of the high price is that a course on using the bands is included. In addition, you’ll find a large network of KAATSU trainers in the U.S. who can come to your home for lessons and workouts.

A second, much more affordable system called BStrong has been developed by Stray-Gundersen, who formerly worked with KAATSU. Instead of an electric pump guided by a small computer, which the KAATSU system has, BStrong uses a small hand pump much like you find with blood pressure devices. It relies on a smartphone app, online videos, and a user’s guide instead of a separate device. With four bands, BStrong sells for around $300.

I’ve found both systems give me a great workout, including that “pump” you get from lifting heavy weights. In addition, there is an added sensation that feels like your skin is momentarily itchy. That’s a sign that blood is really flowing in your smallest capillaries.