Acute Cardiovascular, Metabolic, and Muscular Responses to Blood Flow Restricted Rowing Exercise.

Microgravity leads to a progressive loss in muscular strength, endurance, and aerobic capacity (Vo). Blood flow restricted (BFR) exercise has been shown to elicit rapid gains in muscular strength and Vo. Rowing exercise combined with BFR could be a supplemental countermeasure to maintain preflight muscle function and Vo, especially within future space vehicles with restricted physical volume. There were 20 men who completed 19 min of rowing exercise during CON or BFR in a randomized order. Exercise intensity for all sets was 30% of peak work load achieved during a separate incremental maximal exercise test. Kaatsu training cuffs were inflated around each leg during BFR. Muscle oxygen saturation (Smo₂) and heart rate (HR) were measured throughout exercise and rest. Rate of perceived exertion (RPE) and muscle activation, using surface electromyography (sEMG), were measured during the last 30 s of each exercise set. Blood pressure (BP) and whole blood lactate ([La]) were measured at rest and postexercise. Smo₂ declined significantly in BFR during exercise and rest by 13% and 14%, respectively. HR and RPE showed significant increases during BFR (120.5 ± 5.53 vs. 128.9 ± 9.86 bts · min) (9.8 ± 1.85 vs. 11.8 ± 1.88 arbitrary units). No differences were observed for BP, [La], and sEMG. Findings indicate exercise intensity and cuff pressure elicited acute muscular, cardiovascular, and perceptual responses. BFR rowing exercise could be advantageous as an adjunct for future exercise countermeasures where aerobic and anaerobic exercise may be performed on one device or in limited physical space.