Relationship between % heart rate reserve and % VO2 reserve in treadmill exercise

Area of Science:

• Exercise Physiology
• Cardiovascular Health
• Sports Science

Background:

• Exercise intensity prescription commonly uses % heart rate reserve (%HRR) as a proxy for %VO2max.
• Previous research indicated %HRR aligns with %VO2reserve (%VO2R) during cycling, not %VO2max.
• The equivalence of %HRR and %VO2max during treadmill exercise remains to be clarified.

Purpose of the Study:

• To investigate the relationship between %HRR and both %VO2max and %VO2R during treadmill exercise.
• To determine if %HRR can be used interchangeably with %VO2max for exercise intensity prescription on a treadmill.
• To compare the correlation of %HRR with %VO2max versus %VO2R.

Main Methods:

• Fifty healthy adults underwent maximal Bruce protocol treadmill tests.
• Collected data included resting, submaximal, and maximal heart rate and oxygen consumption.
• Linear regression analyses were performed to compare %HRR against %VO2max and %VO2R.

Main Results:

• The regression of %HRR versus %VO2max showed a significant deviation from the line of identity (intercept -6.1, slope 1.10).
• The regression of %HRR versus %VO2R demonstrated a closer approximation to the line of identity (intercept 1.5, slope 1.03).
• %HRR showed a statistically stronger relationship with %VO2R than with %VO2max (P < 0.001).

Conclusions:

• During treadmill exercise, %HRR is a more accurate indicator of %VO2R than %VO2max.
• Exercise intensity prescription using %HRR on treadmills should be based on %VO2R, not %VO2max.
• These findings align with previous conclusions for cycling exercise, supporting a consistent approach to exercise prescription.