Association between cigarette smoking and erectile tumescence: the mediating role of heart rate variability.

Cigarette smoking deleteriously affects erectile function, and conversely, quitting smoking improves erectile hemodynamics. Underlying mechanisms by which smoking (or reduction of smoking frequency) may affect erectile physiology are not well understood. This study examined the mediating role of heart rate variability (HRV; a marker of sympathovagal balance) among a sample of male chronic smokers from the United States. Sixty-two healthy men (Mage=38.27 years; s.d.=10.62) were assessed at baseline (while smoking regularly), at mid-treatment (while using a nicotine patch) and at follow-up, 4 weeks after patch discontinuation. Cigarette use, frequency-domain parameters of HRV (low frequency (LF), high frequency (HF), LF/HF ratio) and physiological sexual arousal responses (via penile plethysmography) were assessed at each visit. Results were consistent with mediation, in that greater reductions in cigarette use from baseline to follow-up were associated with longitudinal increases in LF, which in turn showed positive relationships with across-time changes in erectile tumescence. Neither HF nor LF/HF ratio mediated the relationship between smoking and erection. In conclusion, HRV mediated the inverse relationship between reductions in smoking and enhancements in erectile tumescence. Results underscore the possibility that cigarette use may deleteriously affect erectile function peripherally, in part, by disrupting cardiac autonomic function.

The effects of nicotine and sucrose on spatial memory and attention.

Both nicotine and sucrose can enhance performance on cognitive tasks. However, little is known about whether nicotine and sucrose could act jointly to augment mental performance. To investigate if there is an interaction between nicotine and sucrose on cognitive behavior, performance on a continuous performance task (CPT) and a spatial memory task was examined in 14 healthy smokers after they had drunk 8 oz of either a sucrose- or aspartame-containing beverage, and then chewed a piece of gum containing either 2 mg nicotine or no nicotine. To assess changes in mood as a function of nicotine and sucrose intake, the profile of mood states (POMS) test was administered three times during each test session. Participants made significantly more correct responses and significantly fewer incorrect responses on the CPT when they received nicotine than when they received the placebo gum. Closer analysis of the data revealed that there was an interaction between sucrose consumption and nicotine intake. Nicotine increased hits and decreased misses when participants were given the sucrose-containing beverage, but not when they were given the aspartame-containing beverage. Neither nicotine nor sucrose affected spatial memory or mood across experimental sessions. However, when data were analyzed for just the first session, participants who drank the sucrose-containing beverage performed significantly better on the spatial memory task than those who drank the aspartame-containing beverage. No gender differences in the effects of nicotine or sucrose on cognitive performance were detected. The results provide support that both nicotine and sucrose have positive effects on cognitive behavior, and that under some conditions the two variables have additive effects on performance.