Are age-predicted equations valid in predicting maximum heart rate in individuals after stroke?

ABSTRACT

PURPOSE: To investigate the validity of six age-predicted maximum heart rate (HRmax) equations after stroke. MATERIAL AND METHODS: Sixty individuals (54 (12) years; 64 (69) months after stroke) were included. A Cardiopulmonary Exercise Test (CPET) performed on a treadmill obtained the HRmax. The most used age-predicted equations were investigated (1) 220-age, proposed by Fox; (2) 206.9- (0.67 × age), proposed by Gellish; (3) 208- (0.7 × age), proposed by Tanaka; (4) 216.6- (0.84 × age), proposed by Astrand; (5) 164- (0.72 × age) and (6) 200- (0.92 × age) proposed by Brawner. RESULTS: No statistically significant agreement was found between the HRmax obtained by the CPET and the one predicted by the equations 1-5 (-0.18 ≤ 95% confidence interval ≤0.79). A significant and moderate agreement was found between the HRmax obtained by the CPET and the one predicted by equation (6) (95% CI= 0.05-0.75; Intraclass Correlation Coefficient= 0.51). Bland-Altman plots showed that equations (1-4) and (6) overestimated the HRmax. Equation (6) presented the lower mean difference. CONCLUSIONS: The equations developed for non-disabled individuals (1-4) are not adequate to be used in individuals after a stroke. Equation (6) (Brawner) showed the best results to be used in individuals after stroke; however, it should be used cautiously.

Prediction equations for maximum heart rate (HRmax) are commonly used to prescribe aerobic exercise for individuals following a stroke.The equations developed for non-disabled individuals are not valid for use with individuals after stroke, leading to an overestimation of the HRmax.An age-predicted HRmax equation developed for individuals with coronary heart disease may provide outcomes that are more accurate for stroke survivors, but care should still be taken when using it.