Healthy lifestyle and heart rate variability in young adults

Background We aimed to determine the association of a comprehensive healthy lifestyle with heart rate variability (HRV), a validated measure of autonomic function. Design This was a prospective cohort study. Methods A population-based sample of 2079 individuals aged 25-41 years without prevalent cardiovascular disease was investigated. The standard deviation of all normal RR intervals (SDNN) during 24-hour electrocardiography was used as main HRV marker. Healthy lifestyle metrics were summed to a validated lifestyle-score ranging from 0=most unhealthy to 7=most healthy. One point was given for each of the following items: never smoking cigarettes; consuming a healthy diet; performing moderate (150min/week) or vigorous (75min/week) physical activity; body mass index (BMI)<25kg/m(2); total cholesterol<200mg/dl; glycated haemoglobin A1c<5.7%; and blood pressure<120 (systolic) and <80mmHg (diastolic). Results Median age of the participants (47% males) was 37 years. Mean SDNN was 153ms and median lifestyle-score was four. A score of 0/1 or 6/7 was found in 5.2% and 11.0%, respectively. In multivariable linear regression analysis with SDNN as the outcome variable, the -estimate (95% confidence interval (CI)) for a one-point increase of the lifestyle-score was 0.14 (0.11-0.17), p<0.0001. This relationship was attenuated but remained significant after additional adjustment for resting heart rate (HR) (-estimate (95% CI) 0.07 (0.07-0.10), p<0.0001) or 24-hour HR (0.04 (0.01-0.07), p=0.003). Conclusions Few individuals adopted a healthy lifestyle in this large contemporary cohort of young adults from the general population. Adopting a healthy lifestyle has an important effect on autonomic function.