Abstract
Introduction: Smoking cessation decreases the risk of heart disease. Alterations in heart rate variability (HRV) have been associated with heart disease. HRV increases immediately after smoking cessation, but it is unknown whether tobacco induced alterations are fully reversible.
Objective: To evaluate whether smoking cessation results in long-term normalization of HRV, and whether normalization was associated with the amount of smoking and physical activity.
Methods: We analyzed 1468 subjects (54% ever smokers) of the SAPALDIA cohort aged ≥50 years, followed prospectively for 11 years. Multivariable linear regressions were used to evaluate the association of smoking status (never/former light/current light/former heavy/current heavy smokers) with HRV. Traditional measures and new more sensitive methods of nonlinear time series analysis were used to assess HRV (i.e. Lyapunov exponent, sample entropy, DFA). Effectof physical activity on HRV was explored in ever smokers, stratifying by heavy and light smokers. All models were adjusted for known confounders.
Results: HRV was not decreased in light ex-smokers compared to never smokers while it remained decreased, in some parameters, until 10% in heavy ex-smokers. In ever smokers, physical activity (≥30 min/week) increased HRV until 30% in light smokers but not in heavy smokers.
Conclusion: These findings give some evidence that heavy smoking triggers irreversible adverse changes in the cardiovascular system. Light ex-smokers presented a normalized HRV. Among them, the ones performing physical activity tended to show an increased HRV. This may support the recommendation to increase physical activity in addition to smoking cessation.
- © 2014 ERS