Evidence of transient heart rate change after smoking cessation

Heart rate slows immediately after smoking cessation but it is unclear whether this is a permanent or transient effect. Examining this issue may improve our understanding of nicotine withdrawal effects. A transient heart rate pattern would suggest that the cardiovascular system adapts chronically to nicotine and requires a period of adjustment to achieve a new homeostasis after cessation. Heart rate was assessed on 110 smokers prior to quitting and at 1, 3, 8, 15, 30, 45, and 60 days post-cessation. For 12 subjects abstinent 60 days, heart rate slowed at day 1 by 8.1 bpm. Heart rate remained below baseline from days 1 through 45, although exhibiting partial recovery, and returned fully to baseline at day 60. The results indicate that heart rate exhibits a pattern of transient change after smoking cessation which seems to be a physiological effect of nicotine withdrawal.