Supplemental Oxygen Does Not Influence Self-selected Work Rate at Moderate Altitude

Area of Science:

• Exercise Physiology
• Altitude Physiology
• Respiratory Physiology

Background:

• Supplemental oxygen enhances aerobic capacity during maximal exercise at moderate altitude.
• The impact of supplemental oxygen on self-selected submaximal exercise intensity at altitude is not well understood.
• Arterial oxygen saturation (SaO2) may influence the regulation of exercise power output through teleoanticipatory mechanisms.

Purpose of the Study:

• To investigate the effects of supplemental oxygen on self-selected work rates during submaximal exercise at moderate altitude.
• To determine if SaO2 influences the regulation of power output at perceived exertion levels of RPE 9 (very light) and 13 (somewhat hard).

Main Methods:

• Twenty-three participants completed familiarization and two blinded experimental trials with varying fractions of inspired oxygen (FIO2).
• Subjects self-selected work rates on a cycle ergometer to match RPE 9 for 5 minutes and RPE 13 for 10 minutes.
• Oxygen consumption (V˙O2), SpO2, and power output were monitored, followed by an incremental test to exhaustion.

Main Results:

• Supplemental oxygen increased SpO2 by approximately 4% and peak power output and V˙O2 during the incremental test.
• No significant increase in average power output was observed during self-selected exercise at RPE 9 or RPE 13.
• Participants could not distinguish between the different FIO2 conditions, indicating imperceptible changes.

Conclusions:

• Slight increases in inspired oxygen concentration at moderate altitude are not perceived by individuals.
• Supplemental oxygen does not appear to alter the self-selected work rate during submaximal exercise at RPE levels up to 13.
• The findings suggest that teleoanticipatory regulation of power output is not significantly affected by small increases in oxygen availability at moderate altitude during submaximal exercise.