Restricted nasal-only breathing during self-selected low intensity training does not affect training intensity distribution

Ludwig Rappelt; Steffen Held; Tim Wiedenmann; Jan-Philip Deutsch; Jonas Hochstrate; Pamela Wicker; Lars Donath

doi:10.3389/fphys.2023.1134778

Restricted nasal-only breathing during self-selected low intensity training does not affect training intensity distribution

Front Physiol. 2023 Apr 20:14:1134778. doi: 10.3389/fphys.2023.1134778. eCollection 2023.

Authors

Ludwig Rappelt^{1

2}, Steffen Held^{1

3}, Tim Wiedenmann¹, Jan-Philip Deutsch¹, Jonas Hochstrate¹, Pamela Wicker⁴, Lars Donath¹

Affiliations

¹ Department of Intervention Research in Exercise Training, German Sport University Cologne, Cologne, Germany.
² Department of Movement and Training Science, University of Wuppertal, Wuppertal, Germany.
³ Department of Sport and Management, IST University of Applied Sciences, Duesseldorf, Germany.
⁴ Department of Sports Science, Bielefeld University, Bielefeld, Germany.

Abstract

Introduction: Low-intensity endurance training is frequently performed at gradually higher training intensities than intended, resulting in a shift towards threshold training. By restricting oral breathing and only allowing for nasal breathing this shift might be reduced. Methods: Nineteen physically healthy adults (3 females, age: 26.5 ± 5.1 years; height: 1.77 ± 0.08 m; body mass: 77.3 ± 11.4 kg; VO₂peak: 53.4 ± 6.6 mL·kg^-1 min^-1) performed 60 min of self-selected, similar (144.7 ± 56.3 vs. 147.0 ± 54.2 W, p = 0.60) low-intensity cycling with breathing restriction (nasal-only breathing) and without restrictions (oro-nasal breathing). During these sessions heart rate, respiratory gas exchange data and power output data were recorded continuously. Results: Total ventilation (p < 0.001, η_p ² = 0.45), carbon dioxide release (p = 0.02, η_p ² = 0.28), oxygen uptake (p = 0.03, η_p ² = 0.23), and breathing frequency (p = 0.01, η_p ² = 0.35) were lower during nasal-only breathing. Furthermore, lower capillary blood lactate concentrations were found towards the end of the training session during nasal-only breathing (time x condition-interaction effect: p = 0.02, η_p ² = 0.17). Even though discomfort was rated marginally higher during nasal-only breathing (p = 0.03, η_p ² = 0.24), ratings of perceived effort did not differ between the two conditions (p ≥ 0.06, η_p ² = 0.01). No significant "condition" differences were found for intensity distribution (time spent in training zone quantified by power output and heart rate) (p ≥ 0.24, η_p ² ≤ 0.07). Conclusion: Nasal-only breathing seems to be associated with possible physiological changes that may help to maintain physical health in endurance athletes during low intensity endurance training. However, it did not prevent participants from performing low-intensity training at higher intensities than intended. Longitudinal studies are warranted to evaluate longitudinal responses of changes in breathing patterns.

Keywords: TID; blood lactate; endurance; heart rate; power; rating of perceived exertion; ventilatory LiT.