An equation to predict peak heart rate for prescribing exercise intensity in middle-aged to older patients requiring hemodialysis

Purpose: Exercise prescription based on a population-specific physiological response can help ensure safe and effective physical interventions. However, as a facile approach for exercise prescription in hemodialysis population that is based on their exercise capacity has not yet been established, the aim of our study was to develop a unique prediction formula for peak heart rate (HR) that can be used in this population.

Methods: This cross-sectional study measured physical function and HR at peak exercise and anaerobic threshold (AT) during cardiopulmonary exercise tests in 126 individuals. Participants were randomly assigned to the development group (n = 78), whose data were used to calculate the prediction equation, or the validation group (n = 48).

Results: The HR reserve in this population was significantly lower (0.44 ± 0.20%) and there was a large discrepancy between conventional age-predicted maximal HR and measured peak-HR values (R = 0.36). The average of the ratio between HR at AT point and peak HR was 85% (95% CI, 83.5%-86.4%). The peak-HR prediction equation was based on resting HR, presence of diabetes, physical dysfunction (gait speed < 1.0 m/s), and hypoalbuminemia (< 3.5 g/dL). It showed high prediction accuracy (R² [95%CI] = 0.71 [0.70-0.71]) with similar correlation coefficients between the development and validation groups (R = 0.82).

Conclusion: Aerobic exercise based on estimated peak HR < 85% obtained from the equation in this study may enable safe and effective physical intervention in this population.