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 (HR_max) 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 HR_max. 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 HR_max 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 HR_max 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 HR_max. 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.

IMPLICATIONS FOR REHABILITATION

• Prediction equations for maximum heart rate (HR_max) 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 HR_max.

• An age-predicted HR_max 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.

Keywords:

• Aerobic exercise
• cardiopulmonary exercise test
• heart rate
• stroke
• validity

Acknowledgements

The authors would like to acknowledge the support from Faculdade Ciências Médicas de Minas Gerais.

Ethics approval

This work was approved by the Institutional Review Board of the Universidade Federal de Minas Gerais.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) [grant number 001]; Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); and Pró-reitoria de Pesquisa da Universidade Federal de Minas Gerais (PRPq/UFMG).