Is there a threshold between peak oxygen uptake and self-reported physical functioning in older adults?

Area of Science:

• Gerontology
• Cardiorespiratory Fitness
• Functional Independence

Background:

• Limited research exists on the direct relationship between measured oxygen uptake (VO2) and self-reported physical function (PF).
• Understanding this link is crucial for assessing functional capacity in aging populations.

Purpose of the Study:

• To investigate the association between peak oxygen uptake (VO2) and physical function (PF).
• To identify a potential threshold of VO2 that differentiates between individuals with low PF (requiring assistance) and high PF (independent).

Main Methods:

• 161 community-dwelling adults aged 65-90 participated.
• Peak VO2 was directly measured, and PF was assessed using a composite score from multiple validated questionnaires.
• Statistical analyses included decision trees, cubic splines, and logistic regression, controlling for covariates like age, gender, and chronic diseases.

Main Results:

• Peak VO2 demonstrated the strongest association with PF (P = 0.004).
• An optimal cut point of 18.3 mL·kg−1·min−1 was identified to distinguish between low and high PF (P < 0.0001).
• Gender differences in PF became non-significant when peak VO2 was included in the model, suggesting VO2 explains some of this disparity.

Conclusions:

• A peak VO2 below 18.3 mL·kg−1·min−1 is associated with significant difficulties in performing daily tasks.
• Differences in cardiorespiratory fitness (peak VO2) may partially explain why women report greater PF impairment.