What is Kaatsu?
Kaatsu (additional pressure in English), also known as Blood Flow Restriction (BFR), traces its origins back to a Japanese temple ceremony in 1966. This fitness trend is gaining in popularity with Olympians, everyday athletes and people undergoing physical therapy, who use Kaatsu to strengthen their muscles and speed up recovery. and rehabilitation centers around the world. It goes by many names, such as occlusion training and hypoxic training, among others. The goal of BFR is to reduce the time it takes to increase your strength and the size of your muscles by restricting blood flow to the muscle that you’re exercising. So, how does this work? Elastic wraps or pneumatic cuffs around your limbs reduce the flow of blood back to your heart, which causes the muscle you’re exercising to become filled with blood. Let me say from the get-go that BFR training is not without controversy and conflicting schools of thought. I’m neither a physician nor a physiotherapist, but after reading numerous articles and scientific journals, my overall impression is very favorable.
Let’s take your biceps, for example. Before you do your dumbbell curls, tightly wrap your upper arms to work your biceps harder. When performed properly, BFR allows blood to enter the muscle via the arteries but restricts the veins to partially prevent blood from leaving the muscle you’re working. Doing this allows you to exercise at a lower intensity yet achieve the feeling of a much harder workout. This engorgement expedites several naturally occurring biochemical reactions, such as secreting nitric oxide, human growth hormone, insulin growth factor-1 and beta endorphins, all of which have differential roles in increasing blood supply, preventing tissue damage, regulating body composition and muscle growth, growing bone and tissue, and suppressing pain. Whenever your brain believes you’re experiencing a difficult physical challenge, it stimulates the pituitary gland to release more growth hormones, which, in turn, leads to muscle growth. “Individuals exercise during the application of BFR to improve muscle mass, muscle strength, reduce pain, improve recovery, increase cardiovascular capacity and augment sports performance,” says physical therapist Nicholas Rolnick.
Physical therapists are using BFR as an alternative to resistance training when moderate loads are not possible to use. This increases strength and muscular growth while using low loads. Moreover, when done properly, BFR provides acceptable gains without the stress on your cardiovascular system and joints associated with normal heavy-load training, according to 2016 study, allowing patients to recover more quickly. Anytime you use a tourniquet-like procedure to limit blood flow, you must be sure that you have the right size of cuff, align it on the body properly and apply the correct amount of pressure. Wider bands restrict blood flow at a lower pressure than narrow bands, although some research states that a narrower cuff width (5-9 cm) reduces the risk of occluding the arteries, compared to a wider cuff or wrap (13+ cm). Current research, however, indicates that BFR training is a safe way to increase muscle size and strength.
How to do it
Warm up by walking or doing some light cycling. Then do 10-12 repetitions of the weight you’re going to use without any wrapping. Then it’s time to wrap the limb you’re going to work out. Think of BFR exercises as something like a warm-up set where you use maybe 30-50% of your normal 1-rep maximum. Traditionally, BFR involves the use of a specialized inflatable KAATSU cuff developed by Dr. Yoshiaki Sato to restrict venous blood flow. Devices such as these allow you to control the pressure accurately and repeat it on future workouts. Now, make sure you don’t restrict both the arteries and the veins, or you won’t get the desired swelling response. It’s the veins you want to restrict! When you restrict blood flow, lactic acid and other metabolites (an intermediate or end product of metabolism) build up to directly stimulate muscle growth through fatigue.
Is BFR training safe?
Before you begin any exercise program, you should consult your physician. I would recommend BFR training for healthy individuals who already incorporate high-intensity weight training in their exercise routines, the exception being people using this in physical therapy to recover from an injury. Research has shown that heavy resistance training (80-100% 1-rep maximum), causes arterial blood pressure to more than double, with heart rates reaching maximal levels, while low-intensity BFR increases blood pressure and heart rate by some 11-13%. In other words, traditional resistance exercise increases blood pressure, heart rate and even cardiac-output changes much more than low-intensity BFR. Groups for whom blood flow restriction might not be appropriate include people with hypertension, uncontrolled diabetes, obesity, kidney disease, arterial calcification, a history of blood clots and medications or conditions causing a higher risk of clotting, venous thromboembolism, vascular diseases, sickle cell anemia, cancer, poor circulatory systems or open fracture, according to experts. If you do BFR training correctly you shouldn’t have to worry about anything – except a little soreness.