{'fraction_non_alphanumeric': 0.05363321799307959, 'fraction_numerical': 0.05478662053056517, 'mean_word_length': 4.525477707006369, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Sex-Specific Maximum Predicted Heart Rate and Its Prognosis for Mortality and MI.

PURPOSE
Maximum predicted heart rate (MPHR) is traditionally calculated by (220-Age). However, this formula's validity has been questioned in women. The purpose of this study was to derive sex-specific formulas for MPHR in a clinical population, and compare their prognostic significance to the traditional formula.


METHODS
This was a retrospective cohort of adults referred for exercise treadmill testing (ETT) between 1991 and 2009. Peak heart rate versus age was plotted by sex, and linear regression analysis was used to derive sex-specific MPHR formulas. Cox models were used to calculate risk of death and MI based on attainment of 85% MPHR using both formulas.


RESULTS
Of 31,090 patients (mean age 55±10 years), there were 2,824 deaths over mean 11±5 years. MPHR was best estimated by 197-0.8xAge for women and 204-0.9xAge for men (P-interaction<0.001). Compared to the sex-specific formulas, the traditional formula overestimated peak heart rate by mean 12±2 bpm in women and 11±1 bpm in men. There were 1,868 patients (6%) who achieved target heart rate using the sex-specific formulas but not with the traditional formula. Achievement of ≥85% MPHR was similarly associated with lower risk of death [adjusted hazard ratio 0.76 (95% confidence interval 0.60-0.97) vs. 0.75 (0.62-0.90)] and MI [0.71 (0.47-1.06) vs. 0.79 (0.57-1.10)] for the sex-specific vs. traditional formula.


CONCLUSIONS
In patients referred for ETT, sex-specific formulas more accurately estimated peak heart rate than the traditional MPHR formula, reclassified 6% of stress tests from inadequate to adequate, and were similarly associated with risk of MI and death.