Vision Loss by Central Retinal Vein Occlusion After Kaatsu Training: A Case Report

Kaatsu training is an exercise method involving the application of pressure to the target muscle, and is being increasingly used in rehabilitation programs for heart disease patients in some hospitals. This method restricts blood flow to the muscles during exercise, and the resultant hypoxia effectively causes muscle hypertrophy and strengthening. However, no medical guidelines or risk factors for its use have been established. We report a case involving a 45-year-old man who suffered from 2 episodes of central retinal vein occlusion (CRVO), both occurring on the day following a Kaatsu training session. As a characteristic of the CRVO and its subsequent complications, the affected eye lost vision despite treatment. The patient had a history of hypertension and diabetes, and thus was at an increased risk of CRVO. Kaatsu training, which changes the heart rate and serum growth hormone levels, may have triggered the onset of CRVO. This case highlights that underlying medical conditions such as hypertension, diabetes, and the consequent inflammation, could be risk factors for vascular side effects resulting from Kaatsu training. Further studies are required before the medical and recreational use of Kaatsu training become widespread.