Sex, age, ethnicity influence physical fitness in exercise treadmill tests
Males and younger individuals tend to perform better on the exercise treadmill test (ETT), demonstrating higher functional capacity and physical fitness, according to a Singapore study presented at the recently concluded 23rd ASEAN Federation of Cardiology Congress (AFCC 2018) in Bangkok, Thailand.
The “[r]ecognition of factors that may influence physical fitness in the young is relevant when prescribing ETT to avoid inconclusive studies due to low workload,” said researchers, adding that ethnicity, aside from age and gender, should also be considered.
Of the 6,967 patients who underwent ETT and had normal findings, 94.1 percent (n=6,554) achieved ≥85 percent of the target heart rate (THR) and were thus included in the analysis. Majority of these participants were male (86.2 percent), and the median age was 40 years. The remaining 413 patients who did not meet the THR cutoff were excluded. [AFCC 2018, abstract P015]
In terms of ethnic background, the study sample was predominantly Chinese (60.7 percent). There were 19.3 percent Malay and 9.7 percent Indian participants, while the remaining 10.3 percent were of other ethnicities.
Overall, the group achieved a mean functional capacity of 12±2.15 metabolic equivalents (METS). Most participants (48.6 percent) scored 10–13 METS, while 10.8 percent scored <10 METS. Less than half (40.6 percent) scored >13 METS.
Among those who failed to reach the 13-METS threshold, majority (63 percent) were administered the ETT due to chest pains. Other major study indications were as an assessment required for reserve military (21 percent) and health screenings (9 percent).
Chest pains were likewise the principal reason for ETT in those with >13 METS functional capacity (66 percent). Pre-reservist assessment (17 percent) and health screenings (10 percent) remained the major study indications in this group.
Health concerns such as shortness of breath and abnormal findings on electrocardiography were rarely the reasons for undergoing ETT, resulting in a total of only 7 percent in both groups.
On multivariate logistic regression analysis, researchers showed that age was an important factor for functional capacity. Relative to those aged 14–30 years, 31–40-year-olds (risk ratio [RR], 0.38; 95 percent CI, 0.33–0.45; p=0.0000) and 41–50-year-olds (RR, 0.31; 0.27–0.36; p=0.0000) were significantly less likely to achieve functional capacity of >13 METS.
Likewise, males were almost four times as likely as females to achieve METS >13 (RR, 3.53; 3.01–4.15; p=0.0000). Those of Chinese background were also approximately 30 percent and 50 percent more likely than Indians (RR, 0.67; 0.56–0.80; p=0.0000) and Malays (RR, 0.55; 0.48–0.64; p=0.0000) to achieve METS >13.
In contrast, those of other ethnic backgrounds were significantly more likely than Chinese participants to reach METS >13 (RR, 1.54; 1.31–1.82; p=0.0000).