Influence of a Six-Week Swimming Training with Added Respiratory Dead Space on Respiratory Muscle Strength and Pulmonary Function in Recreational Swimmers

Warm-Up With Added Respiratory Dead Space Volume Mask Improves the Performance of the Cycling Sprint Interval Exercise: Cross-Over Study

Special breathing exercises performed during warm-up lead to hypercapnia and stimulation of mechanisms leading to increased exercise performance, but the effect of a device that increases the respiratory dead space volume (ARDSv) during warm-up has not been studied. The purpose of this study was to investigate the effect of 10 min warm-up with ARDSv on performance, physiological and biochemical responses during sprint interval cycling exercise (SIE). During four laboratory visits at least 72 h apart, they completed: (1) an incremental exercise test (IET) on a cycloergometer, (2) a familiarization session, and cross-over SIE sessions conducted in random order on visits (3) and (4). During one of them, 1200 mL of ARDSv was used for breathing over a 10-min warm-up. SIE consisted of 6 × 10-s all-out bouts with 4-min active recovery. Work capacity, cardiopulmonary parameters, body temperature, respiratory muscle strength, blood acid-base balance, lactate concentration, and rating of perceived exertion (RPE) were analyzed. After warm-up with ARDSv, P ET CO2 was 45.0 ± 3.7 vs. 41.6 ± 2.5 (mm Hg) (p < 0.001). Body temperature was 0.6 (°C) higher after this form of warm-up (p < 0.05), bicarbonate concentration increased by 1.8 (mmol⋅L-1) (p < 0.01). As a result, work performed was 2.9% greater (p < 0.01) compared to the control condition. Respiratory muscle strength did not decreased. Warming up with added respiratory dead space volume mask prior to cycling SIE produces an ergogenic effect by increasing body temperature and buffering capacity.

Impact of a Breathing Intervention on Engagement of Abdominal, Thoracic, and Subclavian Musculature during Exercise, a Randomized Trial

Background: Breathing technique may influence endurance exercise performance by reducing overall breathing work and delaying respiratory muscle fatigue. We investigated whether a two-month yoga-based breathing intervention could affect breathing characteristics during exercise. Methods: Forty-six endurance runners (age = 16.6 ± 1.2 years) were randomized to either a breathing intervention or control group. The contribution of abdominal, thoracic, and subclavian musculature to respiration and ventilation parameters during three different intensities on a cycle ergometer was assessed pre- and post-intervention. Results: Post-intervention, abdominal, thoracic, and subclavian ventilatory contributions were altered at 2 W·kg⁻¹ (27:23:50 to 31:28:41), 3 W·kg⁻¹ (26:22:52 to 28:31:41), and 4 W·kg⁻¹ (24:24:52 to 27:30:43), whereas minimal changes were observed in the control group. More specifically, a significant (p < 0.05) increase in abdominal contribution was observed at rest and during low intensity work (i.e., 2 and 3 W·kg⁻¹), and a decrease in respiratory rate and increase of tidal volume were observed in the experimental group. Conclusions: These data highlight an increased reliance on more efficient abdominal and thoracic musculature, and less recruitment of subclavian musculature, in young endurance athletes during exercise following a two-month yoga-based breathing intervention. More efficient ventilatory muscular recruitment may benefit endurance performance by reducing energy demand and thus optimize energy requirements for mechanical work.

Acute Effects of Using Added Respiratory Dead Space Volume in a Cycling Sprint Interval Exercise Protocol: A Cross-Over Study

Background: The aim of the study was to compare acute physiological, biochemical, and perceptual responses during sprint interval exercise (SIE) with breathing through a device increasing added respiratory dead space volume (ARDS_V) and without the device. Methods: The study involved 11 healthy, physically active men (mean maximal oxygen uptake: 52.6 ± 8.2 mL∙kg¹∙min^-1). During four visits to a laboratory with a minimum interval of 72 h, they participated in (1) an incremental test on a cycle ergometer; (2) a familiarization session; (3) and (4) cross-over SIE sessions. SIE consisted of 6 × 10-s all-out bouts with 4-min active recovery. During one of the sessions the participants breathed through a 1200-mL ARDSv (SIE_ARDS). Results: The work performed was significantly higher by 4.4% during SIE_ARDS, with no differences in the fatigue index. The mean respiratory ventilation was significantly higher by 13.2%, and the mean oxygen uptake was higher by 31.3% during SIE_ARDS. Respiratory muscle strength did not change after the two SIE sessions. In SIE_ARDS, the mean pH turned out significantly lower (7.26 vs. 7.29), and the mean HCO₃^- concentration was higher by 7.6%. Average La^- and rating of perceived exertion (RPE) did not differ between the sessions. Conclusions: Using ARDS_V during SIE provokes respiratory acidosis, causes stronger acute physiological responses, and does not increase RPE.