%HRmax target heart rate is dependent on heart rate performance curve deflection

Area of Science:

• Exercise Physiology
• Sports Science
• Cardiovascular Research

Background:

• The percent of maximal heart rate (%HRmax) model is a standard for setting training intensities in diverse populations.
• Accurate training intensity prescription is crucial for optimizing performance and rehabilitation.

Purpose of the Study:

• To examine how the heart rate performance curve (HRPC) influences the accuracy of target training heart rate calculations.
• To assess the validity of the %HRmax model across different HRPC patterns.

Main Methods:

• Sixty-two healthy males underwent incremental cycle ergometry to exhaustion.
• Subjects were categorized into four groups based on their HRPC time course (regular, indifferent, linear, inverted).
• Lactate turn points (LTP1, LTP2) and heart rate turn point (HRTP) were identified as performance markers.

Main Results:

• Heart rate at the second lactate turn point (LTP2) was significantly lower in groups with decreasing kHR2 values (indicating less regular HRPC).
• Heart rate at LTP1 and maximal heart rate (%HRmax) did not differ significantly across groups.
• Power output and lactate concentrations at LTP1, LTP2, and maximal workload were comparable between groups.

Conclusions:

• The %HRmax method may overestimate target training heart rate when the HRPC is not regular.
• Individual HRPC variability can affect the reliability of %HRmax-based training intensity recommendations.
• Further research is needed to refine training intensity models considering individual HRPC characteristics.