RESUMO
AIM: This study examined the effect of intermittent breath holding (IBH) on physiological response, including oxygenation in working muscle, to moderate-intensity exercise. METHODS: Thirteen men performed bicycle exercise for 5 min at 65% of peak oxygen uptake with normal breathing (NB) and with IBH. Muscle oxygenation, concentration changes of oxyhemoglobin (ΔOxy-Hb), deoxyhemoglobin (ΔDeoxy-Hb) and total hemoglobin (ΔTotal-Hb), in the right vastus lateralis were continuously monitored using near-infrared spectroscopy (NIRS). Finger capillary blood samples were taken after exercise for analyzing blood lactate concentration (BLa). RESULTS: NIRS parameters showed acute changes to each BH episode in the IBH condition (Total-Hb and ΔOxy-Hb decreased, ΔDeoxy-Hb increased). Accordingly, in the IBH condition, ΔOxy-Hb was lower (P<0.05) and ΔDeoxy-Hb was higher (P<0.05) compared to that in the NB condition, whereas there was no difference in ΔTotal-Hb in the both conditions. BLa levels were greater (P<0.05) in the IBH condition compare to the NB condition. CONCLUSION: These results suggest that IBH during moderate-intensity exercise provokes consistent changes in muscle oxygenation, leading to lower tissue oxygenation. Our data also indicate that exercise with IBH induces higher BLa.
