June 09, 2021 9 min read

If somebody asked you what the best way to build muscle mass was, there’s a good chance that you’d say through high-load resistance training (a.k.a. lifting the heaviest weights for only a few reps at a time).  However, is lifting heavy really the best way to get big?

While it’s a well-known practice for muscle hypertrophy within the physical therapy and sports medicine worlds, blood flow restriction training is less well known within the realms of the gym and heavy lifters.  Yet, it’s an extremely effective way to build muscle mass.

Even though it isn’t all that well known, should you take advantage of blood flow restriction training to induce muscle growth?  We’re giving out all the answers in this complete guide to blood flow restriction training.

What is Blood Flow Restriction (BFR) Training?

The basis of blood flow restriction (BFR) training is manipulating your body’s natural blood flow pattern by cutting off flow to and from a specific part of your body.  This cutting off of blood is also known as vascular occlusion.  The most common way to cut off blood flow is by wrapping a tourniquet device around a particular body part to restrict its typical blood flow movements.

Or, even more practically, some people simply wrap with a resistance band instead. When you use a tourniquet system to restrict blood flow within one of your limbs, you partially cut off arterial blood flow towards your wrapped limb and fully cut off venous blood flow out of your limb. 

As a result, the muscles in your wrapped limb get filled with oxygen-rich blood from your arteries while also getting filled up with deoxygenated blood that can’t escape through your veins. While a part of your body is wrapped up with the tourniquet, you then perform low-intensity skeletal muscle contractions, also known as exercise, to increase either your cardiovascular (aerobic) or muscular strength (anaerobic) capacity. 

All you need to do is wrap the tourniquet proximally to the muscles that you activate during the exercise and get going. Unlike how you normally have to do high-intensity exercises to get stronger both aerobically and anaerobically, you don't have to go quite as hard with BFR training. 

Actually, you only need to do low-intensity aerobics and low-load resistance exercises to make the same cardiovascular and strength gains. That’s because BFR training adds an extra layer of difficulty on top of the low-intensity movements so they become just as challenging as if they were high-intensity.

The BFR method of training was first pioneered by Dr. Yoshiaki Sato in Japan as a way to improve your muscular strength, muscle recovery, rehabilitation, and overall athletic performance while still being very low impact. 

Along with cardiologists Dr. Toshiaki Nakajima and Dr. Toshihiro Morita, the team created the BFR training method in addition to developing their signature exercise program called KAATSU. 

Thanks to the work of these scientists, BFR training is now used all over the world. The real beauty of BFR training is that you make almost the same big gains as you would with heavy-load lifting without doing such highly intensive exercises.

The Top Benefits of BFR Training

So, now you know that BFR helps you make muscular gains without having to do high-intensity training.  But, BFR training does more than just help you build muscle!

Increases Muscle Hypertrophy and Endurance

BFR training results in muscle hypertrophy, which is the increased protein content within your muscle fibers that results in larger muscle size and greater muscle strength.  The greater the protein content in your muscles, the more muscle mass you have. 

In one study conducted by Dr. Yoshiaki Sato himself along with Dr. Naokata Ishii, they found that the overall size and strength of elbow and leg flexor muscles increased significantly more with low-load BFR training than it did in training without blood flow restriction. 

They believe that the accumulation of blood caused greater muscle activation which then grew stronger muscles. Also, BFR training results in greater muscular endurance because it involves lifting lighter weights for longer periods with only short rest periods.  This method of training is ideal for building up muscle endurance.

Improves Cardiovascular Endurance and Aerobic Capacity

When it comes to BFR training, most of the attention is focused on how it can help you build stronger muscles.  But there’s also a significant amount of research showing that BFR is equally as beneficial for your aerobic capacity as it is for your anaerobic. 

In one particular BFR study shown in the Journal of Strength of Conditioning (J Strength Cond Res.), young adults saw improvement in their aerobic fitness and performance when under occlusion pressures greater than 130 mm.  So, if you’re going to give BFR training a try, don’t forget that it's just as good for a cardio day as it is for any lifting day.

Better Regulates Metabolism

Last but not least, BFR training promotes a healthy metabolism.  Having a well-functioning metabolism is essential for maintaining a healthy weight and muscle protein synthesis.  Regardless of your fitness goals, having a healthy metabolism should be on the list of things you want to achieve.

Coagulation - Test with blood sample

A Few Potential Side Effects of BFR Training

Although BFR training is generally considered a safe way to change up your typical exercise plan, it has a few potential side effects including:

  • Dizziness
  • Numbness where the tourniquet device is
  • Fainting

In 2019, a systematic review including meta-analysis conducted by Dr. Cunha Nascimento concluded that there needs to be more research on BFR training to determine how safe it truly is.  And, specifically, more research needs to be done on how blood coagulation could potentially be a dangerous side effect of BFR. 

Therefore, if you're someone who has high blood pressure, diabetes, or a disorder of the circulatory system, then you may want to check with a trainer before doing BFR as it could lead to potentially bad reactions.

The Science Behind BFR Training

You might be wondering now how BFR training is so effective in terms of helping you build up your muscular strength capabilities?  Well, the answer unfortunately isn't all that straightforward because scientists don't have a single answer. 

Yet, there are several different scientifically-backed theories with mounting evidence that might help explain why BFR training works.  In fact, all you need to do is go on PubMed and you’ll see a plethora of BFR research going on right now!  Each of those theories stems back to two of the three ways in which muscles grow, mechanical tension and metabolic stress.

Mechanical tension is when your muscles come under tension while performing a weight-bearing movement.  The tension causes significant increases in your anabolic hormone levels

These hormones, including growth hormone (GH) and insulin-like growth factor (IGF-1), help lead to muscle growth. 

Metabolic stress, also known as acidosis, is a second way in which hypertrophy can occur.  It’s linked very closely to BFR training and how it helps you build such strong muscles.  When you do BFR training, metabolites accumulate in your muscles.  The metabolite accumulation leads to a hormone effect similar to what happens under mechanical tension. 

The hormones put your body in the right muscle-building condition. While there isn’t an exact answer to how BHR training works, these are some of the top theories.  Each of them incorporates either mechanical or metabolic stress.

  1. Cellular swelling causes muscle growth: Cellular swelling is a direct result of metabolic stress.  When the pooling of metabolites and blood that already comes with metabolic stress is added to extra blood accumulated from BFR training, you get an insane amount of swelling in your muscle cells.  That swelling then leads to anabolism of muscle tissue.
  2. Hypoxia kicks in: Hypoxia is a state in which your body is deprived of oxygen due to a lack of oxygenated blood.  In this state, a reaction occurs and your body begins to produce both lactate and hydrogen ions.  Together, these elements help build muscles.  Because BFR training gets your muscles filled up with oxygen-depleted blood, you enter hypoxia and start to build muscle.
  3. Growth hormones ignite:  When there is an increase in lactate and hydrogen ion concentration due to hypoxia, your body begins to up its production of growth hormone and insulin-like growth factor.  With the increased production of these two hormones, collagen synthesis occurs which in turn helps muscles grow stronger.

Is BFR Training Right For You?

Even though research shows that BFR training is great for building strength and endurance, is using BFR right for you?  Consider whether you fall into one of the following groups to get an answer. 

Did You Just Have a Surgery?

If you recently had surgery or are wearing a cast and are partially immobilized, then BFR training is perfect for you.  Even though having muscular strength is important regardless of whether you recently had surgery or not, making sure that you keep up with strength training post-op is particularly important because:

  • Having strong muscles prevents post-op disuse-related injuries
  • Muscle strength reduces operation recovery times
  • It reduces the likeliness of post-op muscular atrophy 

First off, you must keep your body strong post-op even if you’re partially immobilized.  That's because having strong muscles is linked to fewer post-op injuries and overall faster recovery times.  Second, the time spent laying in a bed or wearing a cast is a critical time to work your muscles as the increased sedentary time could contribute to muscle loss. 

Therefore, do BFR training to keep your muscles working.  BFR allows you to get a good workout without carrying too heavy of a load that would cause muscle damage.

Are You Experiencing Muscle Atrophy Due to Aging or a Medical Condition?

The older we get, the more challenging it is to lift heavy loads in the gym because of the strain it creates on our joints.  Yet, despite our age, we probably still want to get stronger and build larger muscles.  The solution to this challenge is occlusion training with BFR.  

Because BFR is super lower resistance yet still leads to muscle growth, it's excellent for people who have age-related challenges or certain medical conditions.  For these people, instead of going to the gym and lifting the heaviest weights, the use of BFR leads to the same results with far less wear and tear on the body.  

And, not only does BFR help elderly populations build up strength, but it also has several other benefits for them including increasing positive bone density markers and functional stability.  While these benefits are good for everyone, they're particularly helpful for those concerned with age-related challenges.

For people with certain medical conditions that make it difficult for them to lift heavy loads, BFR is the way to go.  For example, certain autoimmune and musculoskeletal conditions can make your body weaker and therefore make it harder to lift heavy weights.  The solution is doing BFR with low load resistance.

Are You A Generally Healthy Person?

Last but not least, should healthy people practice BFR training despite being fully able to build muscle through traditional high-load resistance training?  In short, yes!  You don't need to ditch your existing training program for BFR training. 

Rather you can integrate it into your current program for extra muscle-building benefits.  You'll still build strong muscles, but you'll also reduce the load on your body which prevents potentially debilitating injuries. Also, research shows that even athletes performing at the highest levels can benefit from BFR training. 

In one study done on athletes, those who incorporated BFR training into their regular training schedule experienced muscle hypertrophy because the blood restriction added an additional stimulus for building muscles.  In a second study, collegiate athletes saw improvements in their jumping performances after just 8 days of BFR training.

Therefore, if you're a healthy person or even an elite athlete, give BFR training a try to keep challenging your muscles in new ways and increasing strength levels.

How You Can Practice BFR Training

If you’re ready to start BFR training, then give the following blood flow restriction exercises a try.  For each of these exercises, be sure to keep in mind that you should decrease your max speed or max load to a level below your usual benchmark. 

For example, when lifting weights during BFR training, lift 30% to 40% of your one-rep max load rather than 70% to 80%.  Also, do more reps with shorter rest periods than you would at your max load.

Go For a Walk or Jog With With a Wrapped Muscle

​The easiest way to build up cardiovascular strength through BFR training is to simply go for a walk or jog with your thighs wrapped.  Unlike when you typically do cardio and it takes some time to feel the effects of the exercise, you'll feel your heart pounding right away due to the cut-off blood flow. 

Therefore, you can decrease your speed to below your average pace and still get a very effective workout.

powerlifter in knee wraps at powerlifting competition

Do Typical Strength Training Exercises With a Wrapped Muscle

If you want to make BFR training a part of your regular hypertrophy routine, then we suggest doing classic high-load resistance training then finishing it off with ten minutes of BFR. 

If you're having an upper-body day, then round things out with some low-load upper body exercises such as bicep curls or tricep extensions with a tourniquet device wrapped around each arm.  Or, if you're having a lower body day, then wrap the device around your legs and do squats or lunges.

See a Physical Therapist or Sports Med Doctor

If you're an athlete who's trying to improve their performance or you're overcoming an injury, then a light resistance modality of training such as BFR is a solid method to go with. 

With the help of a professional, you could see even greater improvements.  Whether you’re trying to get better athletically or need to recover faster, BFR training will help you do it.

Final Thoughts on Blood Flow Restriction Training

If you’re looking for a new way to change up your strength training routine while getting stronger in the process, then give blood flow restriction training a try.  Even though you won’t be lifting as heavy of weights, the low-load blood flow will do wonders for your muscle mass while reducing the impact on your body.  Even if it looks easy, trust us when we say it will prove just as challenging for your muscles as high-load lifting. 

Bonus tip: If you’re concerned about aging and how BFR training comes in handy as we age, then be sure to check out how anabolic resistance affects us as we get older.


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