Breath-hold diving: respiratory function on the longer term.

WALTERSPACHER, S., T. SCHOLZ, K. TETZLAFF, and S. SORICHTER. Breath-Hold Diving: Respiratory Function on the Longer Term. Med. Sci. Sports Exerc., Vol. 43, No. 7, pp. 1214-1219, 2011. Purpose: Extensive breath-hold (BH) diving imposes high pulmonary stress by performing voluntary lung hyperinflation maneuvers (glossopharyngeal insufflation, GI), hyperinflating the lung up to 50% of total lung capacity. Breath-hold durations of up to 10 min without oxygen support may also presume cerebral alterations of respiratory drive. Little is known about the long-term effects of GI onto the pulmonary parenchyma and respiratory adaptation processes in this popular extreme sport. Methods: Lung function assessments and subsequent measures of pulmonary static compliance were obtained for 5 min after GI in 12 elite competitive breath-hold divers (BHD) with a mean apnea diving performance of 6.6 yr. Three-year follow-up measurements were performed in 4 BHD. Respiratory drive was assessed in steady-state measurements for 6% and 9% CO2 in ambient air. Results: Short-term pulmonary stress effects for static compliance during GI (13.75 L.kPa(-1)) could be confirmed in these 12 divers without exhibiting permanent changes to the lungs' distensibility (7.41 L.kPa(-1)) or lung function parameters as confirmed by the follow-up measurements and for 4 BHD after 3 yr (P > 0.05). Respiratory drive was significantly reduced in these BHD revealing a characteristic breathing pattern with a significant increase in (V) over dot(E) and mouth occlusion pressure (P-0.1) bet ween free breathing and 6% CO2, as well as between 6% CO2 and 9% CO2 (all P < 0.001). Conclusion: BH diving with performance of GI does not permanently alter pulmonary distensibility or impair ventilatory flows and volumes. A blunted response to elevated CO2 concentrations could be demonstrated, which was supportive of the hypothesis that CO2 tolerance is a training effect due to BH diving rather than being an inherited phenomenon.