For who? Baby Boomers, retirees, student-athletes, researchers
For what? Strength, stamina, functional movement, mobility, flexibility, recovery
Many people interchangeably refer to KAATSU as BFR and BFR as KAATSU. In fact, KAATSU is the original BFR.
But the contemporary use of the acronym BFR (Blood Flow Restriction) in the United States and Europe is much different than the original definition of BFR. The seminal paper on KAATSU was described by Drs. Takarada, Takazawa, Sato, Takebayashi, Tanaka, and Ishii in their paper entitle “Effects of resistance exercise combined with moderate vascular occlusion on muscular function in humans”, published in 2000 in the Journal of Applied Physiology.* It was this paper that gave impetus for others to research and publish articles where vascular occlusion gradually was replaced by BFR or Blood Flow Restriction.
But the KAATSU equipment and protocols are different with different outcomes and mechanisms than the BFR equipment and protocols currently practiced in the United States and Europe where Limb Occlusion Pressure (LOP) and other concepts are completely foreign and unnecessary with KAATSU.
This post attempts to explain in easy-to-understand, non-medical terms, why these differences and background. KAATSU was the original BFR because the editors of the first peer-review published studies did not recognize the word KAATSU and required that blood flow restriction or BFR was used. That being said, there are differences between KAATSU and BFR from a medical perspective.
First, let’s review the vernacular used for both BFR and KAATSU:
Restriction (noun): something that restricts, an act of restricting, the condition of being restricted from the Merriam-Webster online dictionary
Occlusion (noun): the act of occluding (or close up or block off or obstruct) from the Merriam-Webster online dictionary
Patent: open, unobstructed, affording free passage from MedicineNet
KAATSU (or 加圧 in Japanese): translated as additional pressure in English.
Blood Flow Restriction (or BFR): a training strategy that involves the use of blood pressure cuffs, tourniquets or occlusion wraps placed proximally around a limb that maintains some arterial inflow while occluding venous return during exercise or rehabilitation. KAATSU was original defined as such.
The Doppler ultrasound images above show the arm’s artery and vein of a male using KAATSU Air Bands at different pressures. The ultrasound shows that the blood flow from the torso to the arm (arterial flow in the artery) and the blood flow back from the arm to the torso (venous flow in the vein) remain open and not occluded or restricted.
Second, how is the pressure in BFR and KAATSU determined?
BFR is commonly started by occluding the brachial systolic blood pressure in the arms or the femoral systolic blood pressure in the legs. Once this pressure, measured in mmHg, is determined, then the BFR bands are set at a certain percentage of that pressure measured in mmHG. In other words, BFR starts by cutting off the arterial flow from the torso to the limbs – and then proceeding with exercise or rehabilitation at a lower pressure.
Some BFR advocates, with inexpensive equipment, recommend using the Borg Scale; a simple self-determination of the perceived exertion on a scale of 1 to 10. The ideal tightness for these BFR (or Occlusion) bands is reportedly 7 on the Borg Scale; but, if there is numbness, the BFR advocates recommend loosening the pressure.
In contrast, KAATSU starts at homeostasis or the stable state of equilibrium in the body with complete patent (i.e., open) arteries and veins. From this point, the “KAATSU Cycle” is used to very gradually and precisely increase the pressure until an “optimal pressure” for each person and each limb is reached (note: the pressure on each limb can be different if there is an injury or significant difference in limb strength, range of motion, or girth).
BFR equipment such as Delfi Portable Tourniquet System for Blood Flow Restriction, Air Cuffs, and Smart Bands start at the point of occlusion.
The user of these types of equipment place the tourniquets and cuffs around their arms and tighten the cuffs until there is no arterial blood flow to the limbs – this point is the well-used term, Limb Occlusion Pressure. In contrast, KAATSU starts at the point of homeostasis where there is complete and open arterial blood flow to the limbs.
Even when the KAATSU Air Bands have significant air pressure inside them, there is no occlusion of arterial or venous flow [see photos above and read here]. The KAATSU Air Bands are specifically designed to allow this condition to occur even at the highest KAATSU pressure possible.
Decades of trials and testing with different material types, material elasticities, and widths enabled the KAATSU inventor, Dr. Yoshiaki Sato to come up with this innovative design. KAATSU protocols were tested and studied at the University of Tokyo Hospital under the supervision of trained and experienced cardiologists including Doctors Nakajima and Morita.
Third, the structure and composition of the KAATSU Air bands are different than all the other BFR and Occlusion Bands on the market today.
BFR or Occlusion bands are engineered to cut off or restrict blood flow – similar to blood pressure cuffs. Their structure and materials are purposefully designed to achieve this objective.
The width of the bands apply a pressure that is effective in reducing or restricting arterial flow.
In contrast, the KAATSU Air Bands are specifically engineered to maintain arterial flow, and only modify the venous flow. The width and the center axis of the inflated KAATSU Air Bands are significantly different than BFR / Occlusion Bands or modified tourniquets / cuffs. This means that the pressure transmission region of the KAATSU Air Bands – especially within the limb on the arteries and veins, is significantly less than the larger / wider BFR bands.
Larger pressure transmission region and effects of BFR bands.
Smaller, narrower pressure transmission region of KAATSU Air Bands.
When the optimal pressure in reached with the KAATSU Air Bands, the KAATSU users see a pinkness or a beefy redness in their limbs as the blood fills the capillary vascular space. When the limbs are moved in this state, there is alternating distension and emptying of the venous/capillary vascular space.
The KAATSU Air Bands gradually apply pressure to the veins. This modifies the venous outflow in the limbs. As the pressure increases during the KAATSU Cycle mode, this modification of the venous outflow eventually modifies the arterial inflow. As exercise or movement continues with the KAATSU Air Bands on, the blood flow into the limbs must soon match the (venous) blood flow out of the limbs. Give about 80% of the body’s blood is in the venous system, there is some capacitance for holding extra blood in the limb, and when that capacity is reached, the blood flow in must match the blood flow out of the limb.
Physiologically, exercise becomes unsustainable when light and easy exercises or movement (e.g., KAATSU Walking or unweighted KAATSU limb movements) are conducted with this impeded circulation. The pO2 and pH gradually (or quickly, depending on the KAATSU intensity) drop to critical levels with even mild exercise. Additionally, higher levels of lactate are generated during KAATSU (compared to non-KAATSU exercise). ATP levels drop as the ADP and Pi levels rise, and ATP dependant electrolyte pumps (e.g. Ca++) cannot maintain proper electrolyte gradients. In this state, there are a significant amount of metabolite and hormonal changes and increases that are subsequently realized.
The fact that KAATSU Air Bands do not approach occlusion pressure , nor result in Blood Flow Restriction, was identified by Professor Alyssa Weatherholt of the University of Southern Indiana, Professor William VanWye of Western Kentucky University, and Johnny Owens of Owens Recovery Science (the exclusive distributor of the Delfi Portable Tourniquet System for Blood Flow Restriction equipment). They presented a study called Pressure Needed to Achieve Complete Arterial Occlusion: A Comparison of Two Devices Used for Blood Flow Restriction Training [see above].
The researchers concluded the wider cuff of the Delfi Portable Tourniquet System for Blood Flow Restriction is able to restrict arterial blood flow at significantly lower pressures compared to the narrow cuffs [KAATSU Air Bands] using the KAATSU Master. The key finding of this study is as follows:
“We were unable to achieve complete arterial occlusion in any participant with the KAATSU cuff.”
The KAATSU equipment is designed and is specifically manufactured to avoid arterial occlusion in the limbs. This fact is precisely why KAATSU was originally defined by Dr. Yoshiaki Sato, the KAATSU inventor, and leading Japanese cardiologists at the University of Tokyo Hospital as a Blood Flow Moderation (BFM) device. KAATSU equipment is specifically not a Blood Flow Restriction (BFR) device.
While the vernacular nuance between BFM and BFR may be overlooked by many (venous flow modification versus arterial flow restriction), the modification of venous flow is critical to understanding the safety and goal of KAATSU, as certified KAATSU Specialists understand.
“There is no part of the KAATSU protocols which tries to achieve arterial occlusion. This is why KAATSU is not BFR, occlusion training, tourniquet training, O-training, or any kind of blood flow restriction modality,” explains Steven Munatones. “This is why KAATSU equipment does not use blood pressure cuffs or surgical tourniquets that are specifically designed to occlude, or manufactured to restrict arterial flow. Rather, the stretchable KAATSU Air Bands are designed with flexible, elastic air bladders that inflate inwards, towards the limb, at very moderate pressures to minimally modify venous flow.
This pressure is gentle on the body and uniform, because the limb is evenly and safely compressed by a bed of air. This principle and practical engineered solution leads to blood pooling in the limb – not arterial occlusion. This fact was independently determined by researchers and the leading Delfi proponent of BFR.
Furthermore, the patented KAATSU Cycle allows normal arterial and venous flow every 20 seconds which means it is safe, effective and gentle for people of all ages (including up to 104 years – see here).
1. The purpose of KAATSU equipment and its protocols is a reduction in venous flow via blood flow moderation, a term first coined in the 1990s by Dr. Sato and Doctors Nakajima and Morita, cardiologists at the University of Tokyo Hospital.
2. The pneumatically controlled KAATSU Air Bands are designed to achieve a reduction in venous flow, and is a very different approach from BFR and widely-promoted use of blood pressure cuffs that are specifically designed to achieve limb occlusion.
3. When the KAATSU equipment is used, its users agree to follow the specific protocols as defined by its inventor, Dr. Sato. Specifically, KAATSU protocols and equipment are designed not to occlude.
4. The stretchable, pneumatically controlled KAATSU Air Bands are not (blood pressure) cuffs. A cuff is a term that refers to devices specifically engineered for limb occlusion.
5. KAATSU Specialists understand the importance of users to know both their Base SKU pressure and their Optimal SKU pressure while using in the KAATSU Cycle and KAATSU Training modes. To refer to KAATSU pressure without reference to both Base SKU and Optimal SKU pressures is misleading.
There is another paper written by Jeremy P. Loenneke, Christopher Fahs, Lindy Rossow, Robert Thiebaud, Kevin T. Mattocks, Takashi Abe, and Michael G. Bemben (Blood flow restriction pressure recommendations: a tale of two cuffs) that addresses this subject from another perspective.
* The first peer-review paper published in the Journal of Applied Physiology is the origin of the term BFR.
Dr. Sato and Professor Ishii knew that their findings would be difficult for the journal editors to accept as is because the word “KAATSU” was unknown in the research and sports world outside of Japan. KAATSU is a Japanese word that is written as 加圧 where the first character (加) means additional and the second character (圧) means pressure. In other words, restriction and occlusion were not the intention of KAATSU; the primary intention was incrementally adding pressure to sufficiently and temporarily modify the venous flow and not impact the arterial flow.
After discussions with the journal editors, the preferred word “KAATSU” was deleted and was instead described in the literature as vascular occlusion – to the grudging disagreement of Dr. Sato and Professor Ishii who most definitely wanted to steer away from the word “occlusion” because that was never their intention or purpose of the KAATSU equipment or protocols.
They knew that there is no arterial limb occlusion of the brachial artery and brachial veins even at high pressures with the pneumatic KAATSU Air Bands.
The ultrasound image on above shows the brachial artery and brachial veins at 300 SKU (mmHg) of a 21-year-old collegiate athlete, but vascular occlusion and, ultimately, BFR or Blood Flow Restriction stuck and was further discussed and defined in the scientific literature.