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

Area of Science:

• Cardiology
• Exercise Physiology
• Neurology

Background:

• Accurate assessment of maximum heart rate (HRmax) is crucial for safe and effective exercise prescription, particularly for individuals recovering from stroke.
• Existing age-predicted HRmax equations are widely used but their validity in specific populations, such as stroke survivors, remains uncertain.

Purpose of the Study:

• To evaluate the accuracy of six common age-predicted maximum heart rate (HRmax) equations in individuals who have experienced a stroke.
• To determine if any of the investigated equations are suitable for estimating HRmax in this clinical population.

Main Methods:

• Sixty stroke survivors (mean age 54 years, 64 months post-stroke) underwent a Cardiopulmonary Exercise Test (CPET) to determine their actual HRmax.
• The measured HRmax was compared against predictions from six established equations: Fox (220-age), Gellish (206.9 - 0.67×age), Tanaka (208 - 0.7×age), Astrand (216.6 - 0.84×age), and two by Brawner (164 - 0.72×age and 200 - 0.92×age).

Main Results:

• No significant agreement was found between measured HRmax and predictions from the Fox, Gellish, Tanaka, and Astrand equations.
• A moderate agreement was observed with the Brawner equation (200 - 0.92×age), with an Intraclass Correlation Coefficient of 0.51.
• Bland-Altman analysis indicated that equations 1-4 and equation 6 tended to overestimate HRmax, with equation 6 showing the smallest mean difference.

Conclusions:

• Age-predicted HRmax equations developed for general populations are not adequate for individuals post-stroke.
• The Brawner equation (200 - 0.92×age) demonstrated the best performance among the tested equations for estimating HRmax in stroke survivors.
• While the Brawner equation offers improved accuracy, its application in this population warrants careful consideration and potential adjustment.