Salivary Mitochondrial DNA Copy Number Is Associated With Exercise Ventilatory Efficiency

Area of Science:

• Exercise Physiology
• Molecular Biology
• Biochemistry

Background:

• Mitochondrial DNA copy number (mtDNAcn) indicates mitochondrial content and responds to exercise.
• Previous studies used invasive methods (muscle, blood) to assess mtDNAcn.
• Salivary mtDNAcn has not been studied in relation to athletic performance.

Purpose of the Study:

• To investigate the association between salivary mtDNAcn and exercise performance markers.
• To explore the potential of salivary mtDNAcn as a non-invasive index for athlete monitoring and exercise prescription.

Main Methods:

• Collected saliva samples from 15 adults for real-time polymerase chain reaction analysis of mtDNAcn.
• Participants completed an exercise challenge test to measure oxygen consumption (V[Combining Dot Above]O2·kg) and ventilatory efficiency (VE/V[Combining Dot Above]CO2).
• Used multiple linear regression to analyze the relationship between salivary mtDNAcn and exercise parameters, adjusting for physical activity.

Main Results:

• Higher salivary mtDNAcn was associated with lower ventilatory efficiency (VE/V[Combining Dot Above]CO2) and higher oxygen consumption (V[Combining Dot Above]O2·kg).
• After adjusting for physical activity, salivary mtDNAcn remained significantly associated with lower ventilatory efficiency (p < 0.05).
• No significant association was found between salivary mtDNAcn and V[Combining Dot Above]O2·kg after adjustment.

Conclusions:

• Salivary mtDNAcn is linked to improved ventilatory efficiency, suggesting it may reflect greater mitochondrial content and enhanced exercise efficiency.
• The non-invasive nature of saliva collection makes salivary mtDNAcn a promising tool for monitoring exercise training and optimizing exercise prescription.