Association between resting heart rate, VOmax and carotid intima-media thickness in middle-aged men.

INTRODUCTION

Low resting heart rate (RHR) and high cardiorespiratory fitness (VOmax) are associated with a reduction in cardiovascular events (CV). Carotid intima-media thickness (CIMT) has been suggested as a predictor of CV. The purpose of this study was to investigate the association between RHR, VOmax and CIMT.

METHODS

The subjects of this study were 707 males aged 40-50 who visited the National Health Center of South Korea, a health examination institution, from 2010 to 2016. RHR was measured using electrocardiogram. RHR was divided into 4 levels (<60 beats per minute; bpm, 60-69 bpm, 70-79 bpm, ≥80 bpm). VOmax was measured by grade exercise test. Subject's VOmax was divided into 3 levels (first, second and third tertiles). CIMT was measured by B-mode ultrasound. Carotid atherosclerosis was defined as CIMT >1 mm.

RESULTS

There was no significant difference in CIMT according to RHR level and there was no correlation between RHR and CIMT. High and middle VOmax group had significant lower CIMT than low VOmax group ( < 0.001). There was also a correlation between VOmax and CIMT (R = -0.129,  < 0.001). The low VOmax group showed 3.56-fold (95% CI, 1.77-7.16) higher relative risk of carotid atherosclerosis than the high VOmax group.

CONCLUSION

These results suggest that cardiovascular fitness index VOmax is associated to CIMT in middle-aged men. In addition, this study shows that VOmax are important indicators for the prevalence of carotid atherosclerosis.