Persistent decrease in heart rate after smoking cessation: a 1-year follow-up study.

The heart rate of 11 smokers was collected throughout their first year of abstinence. One day after smoking cessation, we recorded a significant mean heart rate drop of 9.07 beats per min, from 74.18 to 65.11 beats per min. No significant variation was afterwards detected at any chosen time point (week 1, 2, 3, 4, 6, month 3, 6, 12). In fact, 1 year after cessation the mean heart rate was still 66.36 beats per min, well below initial baseline values. These data indicate that the decrease in heart rate following smoking cessation mostly represents a permanent return to individual normal values in the absence of nicotine self-administration. Nonetheless, three subjects did show a trend toward the recovery of their precessation heart rate and one subject fully recovered it between months 3 and 6 of abstinence. This trend suggests that, while heart rate adaptation to nicotine is largely of an acute nature, there may also be a chronic component. Its role, though usually minor, should become detectable in a few subjects, because of wide interindividual variability.