Which formula correctly converts %VO2 to % HR max?

The correct formula to convert %VO2 to %HR max is derived from research that establishes a relationship between oxygen consumption and heart rate response during physical activity. The conversion takes into account the typical linear relationship that exists between these two variables, allowing clinicians to estimate exercise intensity based on heart rate when direct heart monitoring may not be feasible.

Specifically, the formula in choice A, which is % HR max = (.64 X %VO2) + 37, reflects this relationship in a manner that has been validated through empirical studies. The coefficient (0.64) indicates the proportion of %VO2 that translates into an equivalent heart rate maximum, while the constant (37) adjusts the baseline to reflect individual variations in heart rates at lower exercise intensities. This method provides a useful approximation, especially in a geriatric population where direct measures may sometimes be impractical.

Understanding this formula is valuable for geriatric physical therapists as it helps in designing safe and effective exercise programs for older adults, ensuring that the training intensity aligns with their cardiovascular capacity without exceeding safe limits.