Acute Effects of Breath-Hold Conditions on Aerobic Fitness in Elite Rugby Players.

The effects of face immersion and concurrent exercise on the diving reflex evoked by breath-hold (BH) differ, yet little is known about the combined effects of different BH conditions on aerobic fitness in elite athletes. This study aimed to assess the acute effects of various BH conditions on 18 male elite rugby players (age: 23.5 ± 1.8 years; height: 183.3 ± 3.4 cm; body mass: 84.8 ± 8.5 kg) and identify the BH condition eliciting the greatest aerobic fitness activation. Participants underwent five warm-up conditions: baseline regular breathing, dynamic dry BH (DD), static dry BH (SD), wet dynamic BH (WD), and wet static BH (WS). Significant differences ( < 0.05) were found in red blood cells (RBCs), red blood cell volume (RGB), and hematocrit (HCT) pre- and post-warm-up. Peak oxygen uptake (VOpeak) and relative oxygen uptake (VO/kgpeak) varied significantly across conditions, with BH groups showing notably higher values than the regular breathing group ( < 0.05). Interaction effects of facial immersion and movement conditions were significant for VOpeak, VO/kgpeak, and the cardiopulmonary optimal point ( < 0.05). Specifically, VOpeak and peak stroke volume (SVpeak) were significantly higher in the DD group compared to that in other conditions. Increases in VOpeak were strongly correlated with changes in RBCs and HCT induced by DD warm-up (r∆RBC = 0.84, r∆HCT = 0.77, < 0.01). In conclusion, DD BH warm-up appears to optimize subsequent aerobic performance in elite athletes.