Syncope Episodes and Blood Flow Restriction Training

Abstract

The combination of low-load resistance training [or more recently, neuromuscular electrical stimulation (NMES)] with a moderate local blood flow restriction (BFR) is becoming a widespread training and rehabilitation method. Scientific data indicate the overall safety of BFR, at least in healthy young people. However, it has been associated with side effects, usually minor, and further research is warranted regarding the safety and efficacy of this technique, especially in clinical populations. We found 3 syncope/presyncopal episodes among 21 healthy people (9 men), all occurring in men and during familiarization sessions (in which BFR was applied alone) but not thereafter (BFR sessions combined with NMES): 1 subject experienced a brief syncope and 2 other subjects exhibited presyncopal symptoms (sweating, lightheadedness, and pallor). Our cases are evidence that cardiovascular complications may emerge during BFR. Caution is thus needed in the application of BFR, and gentle familiarization with this training modality is also recommended.