| 제목 |
Is age-predicted maximal heart rate applicable in elderly patients with heart or lung disease? |
| 소속 |
Pusan National University Hospital, Department of Rehabilitation Medicine and Biomedical Research Institute1, Pusan National University School of Medicine and Biomedical Research Institute, Pusan National University Hospital, Department of Rehabilitation Medicine2 |
| 저자 |
Sang Hun Han1*, Tae Woong Yang1, Dong Min Kim1, Mi Kyung Cho1, Ji Won Hong1, Jae Hyeok Chang2, Byeong Ju Lee1† |
Introduction
The maximal heart rate (HRmax) should be known to determine target heart rate (THR) for cardiopulmonary rehabilitation. Age-predicted formula by Fox; HRmax=220-age is widely used, but some researches revealed that it was inaccurate especially in the elderly. Furthermore, no previous studies have confirmed the accuracy of the formula in patients with heart and lung diseases. Therefore, we compared age-predicted HRmax and actual HRmax in the results of the cardiopulmonary exercise test (CPET).
Methods
This study is a retrospective study, and we analyzed medical records of 1060 patients who received CPET at the cardiac and pulmonary rehabilitation center since January 2017 to June 2020. Patients over 70 were defined as the elderly group and the rest as the younger group. The followings were excluded: (1) Failure to achieve 85% (62% for patients taking beta blockers) of the predicted HRmax (2) Peak value of respiratory exchange rate is less than 1.1 (3) Abnormal HR response due to dysrhythmia (4) Less than 20 years old (5) Upper limb ergometer test. The patients were classified according to their risk based on American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR) criteria for patients with heart disease and Michele's for lung disease. Ultimately, 840 patients were included and the general characteristics of the subjects are shown in Table 1.
Result
There was a significant difference between the actual HRmax and the predicted value (P<0.001) in all age groups. When divided by generation, there was no statistically difference between elderly group and younger group (Fig. 1). The moderate-severe risk group showed significant difference than the low risk group. Also, the patients with high minute ventilation/carbon dioxide production (VE/VCO2) slope over 35 showed significant difference compared to the low group. Even in the group with low Body Mass Index (BMI) less than 20kg/m2, there was a difference from the predicted value, and this could be explained by obesity paradox. We suggest a new formula for HRmax of cardiopulmonary patients; predicted HRmax = 200-0.81(age) (Fig. 2).
Discussion
We confirmed that the formula for estimating HRmax is applicable to elderly patients and aging alone is not a hindrance to CPET performance. Patients with moderate to high disease risk, high VE/VCO2 slope, and low BMI should perform exercise tests to achieve the actual HRmax.
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Baseline characteristics of patients
Comparison of actual maximal heart rate and age-predicted maximal heart rate by generation
Scatterplot between age and actual maximal heart rate
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