Breathing valve resistance alters physiological responses during a graded exercise test

Area of Science:

• Exercise Physiology
• Sports Science
• Biomechanics

Background:

• Breathing valves are essential tools in exercise physiology research.
• The resistance offered by different breathing valves can potentially influence physiological measurements.
• Understanding this impact is crucial for accurate data interpretation in sports science.

Purpose of the Study:

• To investigate how breathing valve resistance affects peak aerobic capacity and running economy.
• To compare the influence of high-resistance versus low-resistance valves on exercise performance metrics.
• To assess these effects across different fitness levels and sexes.

Main Methods:

• Participants included endurance-trained males and females, and recreationally active males and females.
• Subjects performed graded exercise treadmill tests using two different two-way non-rebreathing valves with varying resistance.
• Key parameters measured included energy expenditure, ventilation, heart rate, respiratory exchange ratio, running economy, peak aerobic capacity, and time to exhaustion.

Main Results:

• Lower resistance valves (Daniels') resulted in reduced submaximal energy expenditure and improved running economy across all groups.
• Endurance-trained groups showed reduced submaximal oxygen consumption with the low-resistance valve.
• Time to exhaustion increased with the low-resistance valve, while peak aerobic capacity remained unchanged.

Conclusions:

• High-resistance valves (Hans Rudolph 2700) alter the assessment of running economy, submaximal energy expenditure, and time to exhaustion compared to low-resistance valves.
• These alterations occur irrespective of an individual's fitness level or sex.
• Airflow resistance of breathing valves is a critical factor to consider for accurate exercise performance assessments in research and practice.