Understanding Blood Flow Restriction | conditions
Tourniquet tourniquets — those arm and leg bands that look a bit like skinny blood pressure cuffs — made a splash at the Tokyo 2020 Olympics. Some competitive athletes and swimmers such as Michael Andrews and Galen Rupp used them when warming up or cooling down.
BFR has been hailed by some as “the new cupping,” referring to previous Olympics when many swimmers emerged with large circular marks on their skin from the ancient Chinese practice of cupping. Like cupping, BRF is the latest trend in pro sports and fitness that may also have applications for the less athletic set.
What is BFR?
Caroline Brunst, physical therapist and athletic trainer at Ohio State University’s Wexner Medical Center in Columbus, describes training to restrict blood flow as “a novel technique that has gained popularity in recent years.” It’s also known as tourniquet training because it involves the use of a cuff or tourniquet system on the “proximal end of a limb,” which is the upper arm or thigh.
Most systems use a pneumatic tourniquet, in which the band is inflated with air “to a pressure high enough to maintain arterial flow while restricting venous return,” Brunst explains. This means the cuff inflates enough to slow down the pressure return of blood from the muscle to the heart, but is not so narrow that it cuts off all circulation or even restricts blood flow to the working muscle.
This blockage of blood flow from the muscle back to the heart is the key component of the BFR. The presence of the extra blood signals to the brain that this muscle is working harder than it really is. This type of physical stimulation can help build muscle, “similar to higher-intensity, more resistive exercise,” Brunst says. In other words, it increases the effects of strength training.
A 2019 study in the Journal of Applied Physiology that looked at a group of men ages 55 and older over a 14-week period found that BFR combined with low-intensity resistance exercise offered muscle building gains that were similar to those achieved through high-intensity resistance exercise.
Origins of BFR
BFR has older origins, says Steven Munatones, CEO and co-founder of KAATSU Global, Inc., the company that makes the original blood flow modification device called KAATSU.
“KAATSU is a Japanese word meaning ‘extra pressure,'” says Munatones. The idea was first pioneered in 1966 by Japanese physiologist and powerlifter Dr. Yoshiaki Sato developed.
Sato developed the KAATSU system, hailed as the first of the blood flow restriction or blood flow modification systems. There are a variety of other brands and types of blood flow restriction devices on the market today, and they can range from around $25 for the most basic model to several thousand dollars for the high-end options.
How it works
Blood flow modification or restriction devices such as KAATSU are designed to increase pressure on the limbs. Munatones says KAATSU devices “apply gentle pressure to slow venous flow — or blood return from the limbs to the upper body.”
However, the equipment does not block the flow of oxygenated blood from the heart to the muscle,” which is extremely important. While tourniquet and blood pressure cuffs are specifically designed to shut off arterial flow from the torso to the limbs, KAATSU equipment is designed specifically in order to be able to continue the arterial flow unhindered and only slightly change the venous flow.”
Users can set the pressure to variable or constant levels, and you may want to start with very low pressure and build up to a more intense restriction over time. Depending on the program, this pressure typically remains elevated for around 30 to 45 seconds before being released, and can also be cycled at a set series or repetitions.
A small computer controls these pressure changes in the KAATSU device, and users can set it on a variety of programs to achieve their goals, whether it’s building speed, endurance, strength, flexibility, or recovery and rehabilitation.
Munatones says that when your limbs are engorged with blood and you move, “a series of biochemical reactions in the vasculature and brain occur as a result.” He says this involves increased secretion of several hormones and other compounds, including:
- Human Growth Hormone. HGH is a hormone produced by the pituitary gland that aids in muscle growth and cell regeneration. It is useful for building and repairing tissues in the body and is especially important after intense exercise to help repair and build stronger muscles.
- Insulin-like growth factor 1. IGF-1 is a growth hormone that is similar in structure to insulin but acts like HGH in building and repairing muscle in adults.
- Vascular endothelial growth factor. VEGF is a protein that stimulates the formation of new blood vessels. When blood vessels are blocked and less oxygen is reaching the tissues, VEGF is released to help new blood vessels develop and bypass the blockage.
- Brain-derived neurotrophic factor. BDNF is a protein that stimulates cell growth and repair in the brain and nervous system. Exercise encourages the release of BDNF in the brain.
- nitric oxide. NO is a compound that stimulates growth hormone secretion. It is also involved in vasodilation and when blood vessels are compressed it can increase the release of NO.
- plasmalogens. These lipids, or fats, can help protect other lipids and lipoprotein particles from oxidative stress — which is the daily wear and tear that cells undergo from the stresses of daily life, exposure to toxins, and other similar factors. Their function is thus similar to that of antioxidants, which are found in many plant-based foods.
- ceramides. These fats found in skin cells can also help build stronger blood vessel walls.
- Testosterone. The male sex hormone testosterone is known to increase strength and muscle mass.
“It’s this hormonal and metabolic response that leads to athletic gains and improved rehabilitation and recovery,” explains Munatones.
“It’s kind of a biohack,” says Chris Morgan, a Massachusetts-based swimming coach and chief aquatic officer at KAATSU Global. He adds that the device can offer a more efficient way to get the intensity you need for a workout.
For example, instead of 8 by 200 meters (1600 meters total), Morgan has his swimmers swim 16 by 25 meters (400 meters total) to achieve the same end result in a quarter of the time. “And you won’t tear your shoulders either. You will experience fewer ligament tears and less bone pain due to this reduced volume of exercise, especially if you are a land athlete.
Who can use BFR training and equipment?
Strength and competitive athletes, like those who perform explosive sprints or those who want big weightlifting muscles, are obvious candidates to add BFR to their training plans to reap the benefits of less wear and tear on the body.
But other people can benefit from it too. Thomas Roe, an American Council on Exercise-certified personal trainer, endurance athlete, founder of TRoe Fitness, and owner of Local Moves Studio in San Antonio, Texas, says, “An ideal candidate is anyone who has trouble lifting heavy loads, including of your own body weight. Think of the elderly or those who are not physically active prior to surgery or therapy session.”
Munatones agrees that older adults, sedentary people, people who lack mobility and balance, and people with musculoskeletal injuries who are recovering can also be considered ideal candidates.
If you’ve had surgery or are undergoing rehab for an injury, “the traditional strengthening model may not be feasible because of pain, instability, swelling, or other factors,” Brunst says. If this is the case, a sports medicine doctor can use BFR “to facilitate improvements in strength and function.”
The protocol can also help busy individuals get more out of each workout in less time, and even use the equipment while doing housework or walking the dog to get a workout without going to the gym.
Is BFR safe?
Brunst points out that people with certain medical conditions should avoid BFR training. These conditions include:
If you have any of these conditions, Brunst recommends speaking with your doctor and rehabilitation team to determine if BFR is appropriate or if an alternative treatment option might be a better choice.
Nonetheless, Brunst concludes that “when conducted with appropriate athlete selection and with a provider who has been adequately trained in BFR use, it has been shown to be safe with very few reported complications.”
Munatones agrees that KAATSU devices have been proven safe through over 50 years of research and development and “most but not all BFR devices are safe”. On some of the less expensive versions, especially those that more closely mimic a blood pressure cuff, “users can apply too much pressure or apply too much pressure for too long.”
It’s also possible to place the bands in the wrong place or perform exercises that are incompatible with constant pressure. For this reason, KAATSU recommends working with one of their certified practitioners when beginning this therapy. As with any exercise program, it’s best to check BFR use with your doctor before beginning, especially if you have any underlying medical conditions.
Munatones, who suffered a massive heart attack in 2016, says: “I am convinced that the main reason I am alive is that I used KAATSU for over 15 years before I had my heart attack.” He recovered also quickly following the KAASTU protocols for cardiac rehabilitation and is now competing in marathon swimming competitions again.
However, not everyone likes or wants these pressure devices as part of their training or rehab efforts. Roe, for example, does not follow this approach. “BFR is really a personal choice,” he says. “If it works for you, or you get repair and recovery results, then stick with it. Personally, I think most injuries or recovery from surgery can be achieved with deep tissue massage, yoga or Pilates, stretching and strengthening, or swimming.”
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