Nicotine intake is associated with lower body weight in both women and men. Despite its energy content, alcohol consumption is also associated with lower body weight in women but not in men. Each drug may reduce weight by acutely increasing thermogenesis. During four sessions, nicotine (20 μg/kg per dosing) or placebo was given to male and female smokers (n = 9 each) via measured-dose nasal spray every 30 min for 2 h after consumption of diet tonic water with or without alcohol (0.5 g/kg). Each nicotine/placebo dosing was followed by assessment of energy expenditure by indirect calorimetry. Alcohol alone induced no significant effect in men or women, whereas nicotine alone and combined with alcohol induced a significant thermogenic effect in men but not women. These results are consistent with other research suggesting a reduced thermogenic responsiveness to drugs in women and indicate that nicotine must act via appetite suppression to reduce body weight in women. Similarly, these findings do not support the notion that alcohol is inversely related to body weight in women because of excessive acute thermogenesis.

Individual variability in sensitivity to the acute thermic effects of nicotine has been difficult to study because of methodological limitations in the use of smoking to manipulate nicotine dose. This study examined the influence of smoking history, body composition, and, in a subset of subjects, aerobic fitness and physical activity on the thermic effect of nicotine using a measured-dose nasal spray procedure. Following overnight fasting and smoking abstinence, 38 healthy male smokers were intermittently administered a nicotine dose corrected for body weight (15 μg/kg, approx. 1.1 mg for average subject) or placebo on separate occasions in a within-subjects study. Indirect calorimetry was used to assess resting energy expenditure (REE) before and after dosing. Acute thermic response to nicotine ranged from −4.3 to + 10.8 kcal/h (−5.4% to + 12.6% of REE). Thermic response to nicotine was correlated significantly with aerobic fitness (r = 0.58, p < 0.005), physical activity (r = 0.44, p < 0.05), and number of pack-years of smoking (r = 0.43, p < 0.01). Thermic response was marginally correlated with percent body fat (r = −0.23, p < 0.10), but not with body weight (r = −0.04), percent of ideal weight for height (r = -0.10), or lean body mass (r = 0.05). These results indicate that male smokers higher in fitness and activity and with greater smoking exposure histories may experience greater increases in energy expenditure as a result of nicotine intake via smoking. Consequently, variability in these characteristics could help account for some of the variability in weight gain after stopping smoking.

Nicotine and alcohol are often consumed concurrently by smokers. Each drug alone produces significant subjective and cardiovascular responses, but the effects of the two drugs in combination have rarely been examined. Smokers who were moderate alcohol drinkers (n = 18, 9 males and 9 females) participated in four sessions, involving acute administration of nicotine/placebo and alcohol/no alcohol. Subjects abstained overnight from tobacco and alcohol prior to each session. Nicotine (20 µg/kg per presentation) or placebo was administered by measured-dose nasal spray every 30 min for 2 h following consumption of diet tonic water with or without alcohol (0.5 g/kg). Subjective (visual analog scales, Profile of Mood States, Addiction Research Center Inventory) and cardiovascular (heart rate, systolic and diastolic blood pressure) responses were assessed after each nicotine/placebo administration. Nicotine increased head rush, dizzy, and most stimulant effects (i.e. jittery, tension, and arousal and decreased fatigue and relaxed), while alcohol increased intoxication, head rush, dizzy, and jittery, with no other stimulant effects. Nicotine and alcohol generally produced additive subjective and cardiovascular effects when consumed together, although nicotine attenuated sedating and intoxicating effects of alcohol alone. Furthermore, there were several interaction effects on subjective measures involving gender. Nicotine plus alcohol tended to attenuate some subjective effects due to one drug or the other alone in men but enhanced the effects of either alone in women. These findings indicate that nicotine and alcohol generally have additive subjective and cardiovascular effects, but that men and women differentially respond on some subjective measures to the combination of alcohol and nicotine.

The thermogenic effects of nicotine and caffeine during physical activity compared with rest were examined in male and female smokers (n = 10 each). During eight sessions, nicotine (15 micrograms/kg) or placebo was given via measured-dose nasal spray intermittently after consumption of decaffeinated coffee with or without added caffeine (5 mg/kg), followed by assessment of energy expenditure by indirect calorimetry while subjects engaged in standardized, low-intensity cycle ergometer riding (activity) or remained at quiet rest. Results indicated significant thermogenic effects of nicotine and caffeine individually, with the combination of nicotine and caffeine producing additive effects. Expenditure attributable to nicotine, caffeine, or their combination was significantly enhanced during activity compared with rest, but only for males and not females. Plasma nicotine concentrations were influenced by activity and caffeine, but these pharmacokinetic changes did not appear to explain the differences in expenditure. These findings suggest a sex difference in thermogenic effects of nicotine and caffeine during casual physical activity and potentially explain some of the apparent individual variability in expenditure due to tobacco smoking.

Cigarette smoking is associated with reduced body weight, an effect which has often been attributed to acute anorectic actions of nicotine. In this study, male and female smokers (n = 10 each), abstinent overnight from smoking and food, participated in three 2-h sessions, involving intermittent, controlled exposure to their usual cigarette (mean yield = 0·75 mg nicotine), a very low nicotine cigarette (0·1 mg) or an unlit cigarette. Hunger and cigarette craving were assessed throughout each session, which ended with ad libitum consumption of a variety of food items ("lunch"). Plasma nicotine analyses confirmed successful control of nicotine exposure via smoking. Results indicated no differences across cigarette conditions in hunger, in contrast to the sharp differences in cigarette craving. There were no differences in total caloric intake, or in macronutrient or taste selection. There were also no differences in any responses to smoking condition as a function of gender. These findings cast into question the commonly held notion that nicotine or smoking has acute anorectic in smokers.

Nicotine is the primary psychoactive constituent of tobacco smoke, but it is not clear whether the reinforcing effects of cigarette smoking can be attributed solely to nicotine intake. In this study, two groups of male and female smokers participated in three sessions involving intermittent exposure to moderate low, or no nicotine doses via controlled tobacco smoking ("smoke," n = 20) or measured-dose nasal spray ("spray," n = 16). Visual analog scales of subjective effects (VAS) and heart rate (HR) were obtained within 5 min of each dosing. Plasma nicotine levels indicated comparable dosing between methods. For both methods, there were significant nicotine dose effects for most subjective measures and HR. More importantly, the pattern of effects across doses was virtually identical between methods, as nicotine intake via smoking or spray significantly increased HR and the VAS scales of Head Rush and Dizzy, decreased Hunger and Desire to Smoke, and had no effect on Comfortable, Jittery, or Relaxed. These results suggest that rapid nicotine uptake by novel methods may provide effects very similar to nicotine intake by smoking.

Cigarette smoking is linked with lower body weight and may be associated with alterations in caloric intake and energy expenditure (i.e., energy balance). However, the direct effects of smoking on content and pattern of energy balance are unclear because of possible confounding of smoking status with mediating variables related to energy balance, such as body weight and aerobic fitness. The present study compared daily caloric and nutrient intake, participation in leisure time activities, and resting metabolic rate (RMR) following overnight smoking abstinence between male smokers (n = 29) and nonsmokers (n = 21), with groups equated on age, body weight, and fitness. Results showed smokers reported being less active than nonsmokers, but there were no differences in RMR, total caloric intake, or pattern of nutrient intake. These findings indicate that, even after controlling for body weight and aerobic fitness, smoking status is independently associated with a less active lifestyle but may not have any direct effects on dietary content or RMR.

The acute thermogenic effect of nicotine was examined in cigarette smokers under conditions of rest and two levels of low-intensity physical activity comparable to that normally engaged in by sedentary adults. Male and female smokers (n = 10 each) each received 0 (placebo), 7.5, 15, or 30 micrograms/kg nicotine via measured-dose nasal spray once every 30 min for 90 min, with each dose presented on a separate occasion. After each dose presentation, subjects engaged in 10 min of rest or low-intensity activity at 30 or 60 watts (W) using a bicycle ergometer. For males, results indicated that expenditure attributable to nicotine was more than twice as large during 60-W activity compared with rest, while that during 30-W activity was intermediate. For females, expenditure attributable to nicotine was generally similar to that of males during rest and 30-W activity but was significantly lower during 60-W activity, indicating an apparent "inverted-U" relationship with activity intensity. The enhanced effect of nicotine was specific to energy expenditure, since heart rate showed dose-dependent changes that were generally similar regardless of activity level. These findings confirm a mediating influence of physical activity level on the acute metabolic effect of nicotine, especially in males, and may have implications for explaining individual differences in body weight changes due to tobacco smoking and cessation.

Nicotine may decrease perceived exertion during physical work, which may be a potentially reinforcing effect of tobacco smoking. This study examined the effects of nicotine on ratings of perceived exertion (RPE) during low-intensity physical activity representative of activity normally engaged in by adult smokers. Ten male and 10 female smokers participated in four morning sessions, one for placebo and each of three nicotine doses (7.5, 15, and 30 micrograms.kg-1), which were administered by measured-dose nasal spray. Using a bicycle ergometer, subjects exercised at each of two lower power outputs (30 and 60 W) before and after nicotine dosing, while RPE and cardiovascular measures of heart rate and systolic and diastolic blood pressure were obtained. Results indicated no significant effect of nicotine on RPE for either males or females. In contrast, nicotine significantly increased each cardiovascular measure during activity, confirming that cardiovascular responses during exercise do not mediate RPE. Thus, nicotine did not influence perception of exertion during low-intensity physical activity.

Performance on finger-tapping and handsteadiness, tasks opposite in response requirements, was compared between male smokers and nonsmokers (n = 10 each) on two occasions, once following intake of nicotine (15 μg/kg) by measured-dose nasal spray and once following placebo. Compared with nonsmokers, smokers had significantly greater increase in finger-tapping speed due to nicotine. On the other hand, smokers tended to have improved performance on handsteadiness (i.e., less involuntary movement) due to nicotine, while nonsmokers had impaired performance, although this difference was not significant. Nicotine-induced changes in performance on each task were inversely related, suggesting specificity of the behavioral effects of nicotine depending on task demands, rather than a generalized effect. These effects of nicotine on behavioral performance may be important in understanding the reinforcing value of nicotine intake, and differences in effects as a function of smoking history may suggest chronic adaptation to nicotine.

The thermogenic effect of nicotine intake after calorie consumption was investigated to determine if nicotine influences metabolic response to a calorie challenge. Smokers and nonsmokers (10 males in each group), matched for body weight, age, and physical fitness, each participated in four sessions that involved consuming a liquid calorie load (4.77 kcal/kg body wt) or water, followed by nicotine (15 micrograms/kg body wt) or placebo via nasal spray every 20 min for 2 h. Energy expenditure was significantly increased above baseline resting metabolic rate (RMR) over the 2 h by nicotine alone (6.5% of RMR, p less than 0.01). However, the combined effect of nicotine after calorie load (20.1% of RMR, p less than 0.001) was not significantly greater than the effect of calorie load alone (18.4% of RMR, p less than 0.001). Smokers and nonsmokers did not differ in baseline RMR or in response to nicotine or calorie load. These results confirm the thermogenic effect of nicotine but suggest that the effect of nicotine after calorie consumption is less than additive.

SUMMARY 1. In two separate studies using healthy male smokers as subjects, the acute cardiovascular effects of a measured dose of nicotine (15 μg/kg) were examined in conjunction with light physical activity and following consumption of a meal, conditions typical of nicotine intake via smoking. 2. Increases in heart rate and systolic blood pressure attributable to nicotine were similar during rest, physical activity, and following eating, demonstrating additivity with the cardiovascular effects of activity and a caloric load. Diastolic blood pressure was less affected by nicotine. 3. These results indicate that cardiovascular activity is acutely increased following nicotine (smoking) regardless of other influences on the cardiovascular system. Such effects may help explain increased risks of acute cardiac abnormalities due to smoking.

Nicotine's effects on reducing perception and/or hedonics of sweet and fat taste may lead to less intake of sweet tasting, high-fat foods by smokers, helping to explain their generally lower body weights. Smokers and nonsmokers (n = 10 males each) rated perception (intensity and sensitivity) and hedonics (liking) of sweet/fat taste in milk samples varying both in sucrose (0, 5, 10, 20% w/w) and fat (0.1, 3.5, 11.7, 37.6% w/w) concentrating on two occasions, once following intermittent presentation of nicotine (15 μg/kg) via measured dose nasal spray and the other following placebo. Nicotine significantly reduced perceived intensity of fat but not sweet taste and had no effect on sensitivity to either taste. There was no effect of nicotine on hedonics of sweet/fat taste. On the other hand, although there were no differences between smokers and nonsmokers in perception of sweet or fat, hedonics of sweet/fat taste was reduced in smokers regardless of nicotine or placebo intake. Thus, nicotine may acutely decrease fat taste perception without influencing sweet/fat hedonics, while long-term exposure (i.e., being a smoker) may produce chronically decreased taste hedonics without altering perception.

Christman, J. V.; Sexton, J. E.; Dupaul, L. M.; Hultquist, C. M.; Willey, E. S.; Alpert, B. S. Author Information