Cardiorespiratory and muscle oxygenation responses to voluntary hypoventilation at low lung volume in upper body repeated sprints

To investigate the impact of voluntary hypoventilation at low lung volumes (VHL) during upper body repeated sprints (RS) on performance, metabolic markers and muscle oxygenation in Brazilian Jiu-Jitsu (BJJ) athletes.

Eighteen male well-trained athletes performed two randomized RS sessions, one with normal breathing (RSN) and another with VHL (RS-VHL), on an arm cycle ergometer, consisting of two sets of eight all-out 6-s sprints performed every 30 s. Peak (PPO), mean power output (MPO), and RS percentage decrement score were calculated. Arterial oxygen saturation (SpO₂), heart rate (HR), gas exchange, and muscle oxygenation of the long head of the triceps brachii were continuously recorded. Blood lactate concentration ([La]) was measured at the end of each set. Bench press throw peak power (BP_PP) was recorded before and after the RS protocol.

Although SpO₂ was not different between conditions, PPO and MPO were significantly lower in RS-VHL. \({\dot{\text{V}}}\) $\dot{\text{V}}$ _E, HR, [La], and RER were lower in RS-VHL, and VO₂ was higher in RS-VLH than in RSN. Muscle oxygenation was not different between conditions nor was its pattern of change across the RS protocol influenced by condition. [La] was lower in RS-VHL than in RSN after both sets.

Performance was significantly lower in RS-VHL, even though SPO₂ was not consistent with hypoxemia. However, the fatigue index was not significantly affected by VHL, nor was the neuromuscular upper body power after the RS-VHL protocol. Additionally, [La] was lower, and oxygen consumption was higher in RS-VHL, suggesting a higher aerobic contribution in this condition.