If you\u2019re looking to improve your workout routine, especially if you\u2019re focused on building muscle, you might love the trick Hailey Bieber uses. The bands wrapped around her thighs aren\u2019t an aesthetic choice or one of the latest fashion trends. They\u2019re BFR bands, used for a method known as Blood Flow Restriction, which involves deliberately restricting blood flow during exercise.<\/p>\n
Although BFR may seem like the latest social media craze, its roots go back to 1960s Japan, where it was known as Kaatsu training. The method was invented by Dr. Yoshiaki Sato after he noticed numbness in his calves while sitting in the traditional Japanese position known as seiza for an extended period. He realised that deliberately and carefully reducing blood flow to the muscles could trigger cellular stress similar to that experienced when lifting heavy weights.<\/p>\n
Related: Harvard Confirms This Type of Exercise Is Key to Longevity, Yet Many People Skip It<\/a><\/p>\n Professional athletes have been using BFR for decades, and the method is also popular in physical therapy, particularly for muscle rehabilitation. Now, thanks to the growing popularity of biohacking methods, it\u2019s making its way into gyms as well.<\/p>\n How Does BFR Work and What Is It Used For?<\/p>\n BFR is used on the limbs and involves placing specialised bands around the uppermost part of the arms (just below the shoulders) or legs (at the top of the thighs). The aim is to partially restrict venous blood flow (the return of blood from the muscles to the heart), while allowing arterial blood flow (which delivers oxygen to the muscles) to remain partially open. Creating these specific conditions of restricted blood flow causes oxygen to be depleted more quickly and metabolic by-products, such as lactic acid, to accumulate. The body interprets this as extremely demanding exercise and responds by activating metabolic pathways responsible for muscle growth and the release of growth hormone, even when you\u2019re lifting very light weights.<\/p>\n