Delayed heart rate recovery after exercise ups risk of MetS in men
A lowered autonomic function, measured as the delayed heart rate recovery (HRR) after exercise, increases the risk of cardiometabolic syndrome (MetS) in otherwise healthy men, reports a new study.
Researchers enrolled 2,740 men (mean age 47.7 years) who had no evidence of MetS, cardiovascular disease, hypertension and diabetes at baseline. Participants were asked to perform peak treadmill exercise testing. This was followed by a recovery protocol consisting of a 2-minute slow walking without incline, during which HRR was calculated.
After a mean follow-up period of 5 years, 845 developed MetS while 1,895 did not. The resulting incidence rate of MetS was 61 per 1,000 person-years. Those who developed MetS tended to have higher body mass index and waist girth (p<0.001 for both).
Categorizing the participants according to quartiles of 1-minute HRR, researchers found that those in the lowest vs highest quartile were significantly more likely to develop MetS. This relationship remained significant even after adjusting for confounders such as body mass index, uric acid, smoking and alcohol intake (relative risk [RR], 1.24; 95 percent CI, 1.02–1.51).
Results were more pronounced when 2-minute HRR was used (first vs fourth quartile: RR, 2.02; 1.58–2.60). In contrast, when HRR was taken as a continuous variable, no significant correlations were observed (1-minute: RR, 0.99; 0.98–1.00; 2-minute: RR, 0.98; 0.97–0.99).
The present findings suggest that a delay in HRR after exercise testing increases the risk of incident MetS, independent of important confounders such as oxygen uptake and resting heart rate, said researchers.