Controlled hyperventilation after training may accelerate altitude acclimatization

The positive effects of combined breathing techniques and cold exposure on perceived stress: a randomised trial

A pranayama-inspired breathing technique, cold exposure, and their combined application were assessed for their potential to reduce perceived stress in adults and compared to a control group. An experiment involving four groups was conducted, yielding separate cells for breathing technique-only and cold exposure-only, as well as a combined treatment and a control group. Eighty-six individuals participated in the study. Perceived stress is measured employing the 10-item version of the Perceived Stress Scale (PSS-10) and the 20-item version of the Perceived Stress Questionnaire (PSQ). The instruments exhibit a substantial correlation (r = 0.842, p < 0.001). The combined group exhibited a medium to large positive effect on perceived stress compared to the control group. The breathing technique and cold exposure on their own were not found to yield substantial effects, indicating synergies between both exercises. Combinations of breathing techniques and cold exposure may be employed to decrease individuals' perceived stress.

Voluntary Increase of Minute Ventilation for Prevention of Acute Mountain Sickness

This study evaluated the feasibility and efficacy of voluntary sustained hyperventilation during rapid ascent to high altitude for the prevention of acute mountain sickness (AMS). Study subjects (n=32) were volunteer participants in a 2-day expedition to Mount Leoneras (4954 m), starting at 2800m (base camp at 4120 m). Subjects were randomized to either: 1) an intervention group using the voluntary hyperventilation (VH) technique targeting an end-tidal CO₂ (ETCO₂)<20 mmHg; or 2) a group using acetazolamide (AZ). During the expedition, respiratory rate (28±20 vs. 18±5 breaths/min, mean±SD, P<0.01) and SpO₂ (95%±4% vs. 89%±5%, mean±SD, P<0.01) were higher, and ETCO₂ (17±4 vs. 26±4 mmHg, mean±SD, P<0.01) was lower in the VH group compared to the AZ group - as repeatedly measured at equal fixed intervals during the ascent - showing the feasibility of the VH technique. Regarding efficacy, the incidence of 6 (40%) subjects registering an LLS score≥3 in the VH group was non-inferior to the 3 (18%) subjects in the acetazolamide group (P=0.16, power 28%). Voluntary increase in minute ventilation is a feasible technique, but - despite the underpowered non-inferiority in this small-scale proof-of-concept trial - it is not likely to be as effective as acetazolamide to prevent AMS.