Q: What is blood flow restricted exercise? Is it effective—and safe?
A: According to some studies, blood flow restricted (BFR) exercise can produce some pretty impressive results, though it’s not for everyone. To do it, you wrap an elastic band, such as an Ace bandage, around your arm or leg while you work out.
The idea is that by restricting blood flow to your muscles, you can stimulate muscle growth using lighter weights.
This could be especially useful for older people who can’t lift weights heavy enough to get benefits due to joint problems (such as arthritis) or muscle loss—and for people who have had injuries or surgery (for example, knee or hip surgery).
In a small study in the Journal of Applied Physiology in 2010, older men who did leg extensions with cuffs on had greater muscle protein synthesis than when they did the exercise without the cuffs, with results similar to that seen when young people do high-intensity strength training.
In another study in 2010, in the Journal of Gerontology, older people who did treadmill walking with cuffs around the tops of their legs had significant increases in muscle size and strength after ten weeks, compared to those who walked without cuffs.
How BFR exercise may work is not clear. Reducing oxygen to a muscle causes alterations in the muscle’s metabolism as well as changes in hormones and other factors that can affect the amount of force the muscle produces. BFR may also activate a certain type of muscle fiber called fast twitch.
Many people find the exercise uncomfortable, however. And it’s not without risks. It can cause bruising where the cuff or band is applied, as well as numbness and lightheadedness. Plus, it may temporarily raise blood pressure and heart rate (more so than regular weight lifting) and increase the risk of blood clots. More studies are needed to make sure any long-term benefits of BFR exercise outweigh any short-term risks.
If you are thinking of doing BFR exercise, talk to your doctor first. You may not be a good candidate if you have a clotting disorder, hypertension, or other cardiovascular condition.
If your doctor gives you the okay, you should work with a physical therapist or certified trainer, who can make sure you are doing it properly and safely.