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Effects of immersion and static lung loading on submerged exercise at depth
Undersea Biomedical Research
|September 1, 1979
Summary
Static lung loading minimally impacted exercise physiology during submerged exercise. However, a +10 cmH2O load significantly reduced exercise-induced dyspnea, improving maximal performance at high pressures.
Area of Science:
- Environmental Physiology
- Exercise Physiology
- Respiratory Physiology
Background:
- Submerged exercise presents unique respiratory challenges due to increased ambient pressure and breathing gas density.
- Understanding the effects of static lung loading on physiological responses is crucial for optimizing performance and safety in hyperbaric environments.
Purpose of the Study:
- To investigate the impact of static lung loading on physiological parameters during submerged exercise.
- To assess the influence of static lung loading on exercise-induced dyspnea and maximal exercise capacity at various pressures.
Main Methods:
- Three male subjects performed maximal and submaximal submerged exercise in a prone position at pressures from 1.45 to 6.76 ATA.
- Static lung loading was applied in a range from +20 to -20 cmH2O using a low-resistance breathing apparatus.
- Measurements included oxygen consumption (VO2), carbon dioxide production (VCO2), ventilation (VE), heart rate, end-tidal PCO2, vital capacity (VC), expiratory reserve volume (ERV), and dyspnea scores.
Main Results:
- Static lung loading had minimal effects on VO2, VCO2, VE, heart rate, and end-tidal PCO2.
- Increased breathing gas density significantly affected these physiological parameters.
- Immersion reduced VE at a given VO2 and increased tidal volume (VT) and alveolar ventilation (VA) at a given VE.
- Positive static lung loads increased VC and ERV.
- A static load of +10 cmH2O minimized exercise-induced dyspnea, enabling maximal exercise at 6.76 ATA.
Conclusions:
- Static lung loading has a limited effect on core physiological responses during submerged exercise.
- Breathing gas density and immersion itself are more significant factors influencing respiratory and cardiovascular responses.
- Static lung loading, particularly a positive load of +10 cmH2O, can effectively mitigate exercise-induced dyspnea and enhance exercise capacity under hyperbaric conditions.