Cognitive impairments after maximal repeated breath-holding in elite breath-hold divers

Breath-hold (BH) training over several years may result in mild but persistent neurocognitive impairment. Paradoxically, the acute effects of repeated BH generating intermittent hypoxia on neurocognitive functions are still poorly understood. Therefore, we decided to examine the impact of five-repeated maximal BH on attention, processing speed, and reasoning abilities.

Thirty six men separated in 3 groups (12 elite BH divers: EBHD; 12 novice BH divers: NBHD; and 12 non BH divers: CTL) performed before and after 5 maximal BHs, neuropsychological computerized tasks sensitive to hypoxia. Heart rate (HR) and peripheral oxygen saturation were recorded continuously during all tests.

Immediately after the five BHs, all the participants presented lower response time on the visual reaction task. EBHD did not exhibit difference in neuropsychological performance compared to NBHD and CTL, despite enduring longer BH durations.

Regardless of BHD training level, repeated maximal BH may affect certain aspects of neuropsychological performance, in particularly visual reaction times. However, elite BHDs may have developed adaptive mechanisms that allow them to maintain their neurocognitive function at levels comparable to those of less trained BHDs and CTL, even with a higher dose of hypoxia.