Key result
Females older than 50 years attained a lower percentage of age-predicted maximal heart rate (82.5% vs 94.37%) and could not reach the fourth stage of the Bruce protocol, suggesting 80% should be considered normal rather than chronotropic incompetence.
Why the study?
There is a lack of consensus regarding which regression equation to use for calculating age-predicted maximal heart rate during exercise stress testing.
Does the standard 220-age formula accurately predict maximal heart rate during treadmill stress testing in females older than 50 years?
Cross-Sectional (n=70)
No
Does the standard 220-age formula accurately predict maximal heart rate during treadmill stress testing in females older than 50 years?
The standard 220-age formula overestimates maximal heart rate in females over 50, suggesting 80% of predicted max HR should be considered normal to avoid misdiagnosing chronotropic incompetence.
There is lack of consensus regarding regression equation to be used for calculation of age predicted maximal heart rate for evaluation of exercise stress test. We evaluated stage wise increase in heart rate during treadmill stress testing using Bruce protocol in seventy normal individual after excluding various confounding factors. We analyzed the data in two genders of different age groups and calculated the statistical significance of difference between different groups. Formula of 220-age was used for calculation of age predicted maximal heart rate. Females older than fifty years could not reach fourth stage. Total increase in heart rate and percentage of age predicted maximal heart rate were also lower in females older than fifty years. Our study shows that 80% of age predicted maximal heart rate is normal for females older than fifty years and should not be ‘considered as chronotropic incompetence.’ There is need for developing a different regression equation for calculation of age predicted maximal heart rate for females older than fifty years.
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Mittal SR (2023) conducted a cross-sectional in Normal individuals (n=70). Female sex (age > 50 years) vs. Male sex (age > 50 years) was evaluated on Percentage of age-predicted maximal heart rate attained (p=>0.1). Females older than 50 years attained a lower percentage of age-predicted maximal heart rate (82.5% vs 94.37%) and could not reach the fourth stage of the Bruce protocol, suggesting 80% should be considered normal rather than chronotropic incompetence.
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