Is V̇O2 suppressed during nonapnoeic facial submersion?
The mammalian dive response (DR) is described as oxygen-conserving based on measures of bradycardia, peripheral vasoconstriction, and decreased ventilation (V̇E). Using a model of simulated diving, this study examined the effect of nonapnoeic facial submersions (NAFS) on oxygen consumption (V̇O2). 19 participants performed four 2-min NAFS with 8 min of rest between each. Two submersions were performed in 5 °C water, 2 in 25 °C water. Heart rate (HR) was collected using chest strap monitors. A tube connected to the inspired port of a non-rebreathing valve allowed participants to breathe during facial submersion. Expired air was directed to a metabolic cart to determine V̇O2 and V̇E. Baseline (BL) HR, V̇O2, and V̇E values were determined by the average during the 2 min prior to facial submersion; cold shock response (CSR) values were the maximum during the first 30 s of facial submersion; and NAFS values were the minimum during the last 90 s of facial submersion. A 2-way repeated-measures ANOVA indicated that both HR and V̇E were greater during the CSR (92.5 ± 3.6 beats/min, 16.3 ± 0.8 L/min) compared with BL (78.9 ± 3.2 beats/min, 8.7 ± 0.4 L/min), while both were decreased from BL during the NAFS (60.0 ± 4.0 beats/min, 6.0 ± 0.4 L/min) (all, p < 0.05). HRCSR was higher and HRNAFS lower in 5 °C versus 25 °C water (p < 0.05), while V̇E was greater in 5 °C conditions (p < 0.05). V̇O2 exceeded BL during the CSR and decreased below BL during the NAFS (BL: 5.3 ± 0.1, CSR: 9.8 ± 0.4, NAFS: 3.1 ± 0.2 mL·kg-1·min-1, p < 0.05). The data illustrate that NAFS alone contributes to the oxygen conservation associated with the human DR.
['Anderson|Sarah|S|', 'Chamberlain|Maggie R|MR|', 'Musgrove|Samantha|S|', 'Partusch|Antonia|A|', 'Tice|Keagan R J|KR|', 'Thorp|David B|DB|']
D000328:Adult D003080:Cold Temperature D065508:Diving Reflex D015536:Down-Regulation D005145:Face D005260:Female D006339:Heart Rate D006801:Humans D007101:Immersion D008297:Male D008954:Models, Biological D018670:Monitoring, Ambulatory D010101:Oxygen Consumption D012123:Pulmonary Ventilation D013997:Time Factors D055815:Young Adult
facial submersion dive response oxygen consumption cold shock response choc hypothermique consommation d’oxygène réponse à la plongée submersion faciale