The primary aim of this project is to test the effect of exercise on acute nicotine withdrawal. Acute nicotine withdrawal is characterized by a complex array of symptoms associated with increased risk of relapse among individuals attempting smoking cessation. The available remedies do not target all aspects of withdrawal. For example, pharmacologic treatments reduce withdrawal-based craving, but have no effect on cue-related craving, altered sleep, and mood disturbances during withdrawal. Therefore, non-pharmacologic behavioral techniques with the potential to attenuate persistent withdrawal symptoms are needed. We hypothesized that exercise can be a valid non-pharmacologic strategy to improve these domains. The goal of the proposed work is to test: 1) the effects of exercise on mood, objective measures of sleep, and cue reactivity; 2) the effects of exercise at a given intensity and duration, after a short (few hours) and more prolonged (24 to 72 hours) abstinence from smoking; and 3) the effects of exercising in the morning versus exercising in the evening on the proposed outcome domains. We plan to implement a within-subject design that will allow us to collect measures for each subject aged 18 to 39 in four different conditions: 1) ad libitum smoking; 2) evening exercise after 2 to 72 hours of abstinence; 3) morning exercise after 2 to 72 hours of abstinence; and 4) no exercise after 2 to 72 hours of abstinence. Exercise will be conducted at a fixed and monitored dose and duration. By collecting morning and evening measures of withdrawal symptoms and cue reactivity, we will also test whether the effects of exercise in reducing withdrawal symptoms and cue reactivity will show a prolonged effect beyond the minutes/hours immediately after the exercise bout. We also hypothesize that the timing of exercise may have differential effects on different aspect of withdrawal. The proposed work will allow us to examine the extent to which exercise, a promising nonpharmacologic behavioral treatment method, can attenuate key symptoms of withdrawal recognized to impede abstinence efforts. A better understanding of these effects will allow us to implement exercise at the time of day that may be more troublesome for the individual attempting to quit. The development of new behavioral methods for attenuating withdrawal symptoms will be directly transferable to smoking cessation treatments aimed at reducing withdrawal symptoms and aiding efforts to avoid relapse after quitting smoking. This application is being submitted in response to RFA-DA-09-013 (Interactions between Physical Activity and Drug Abuse). PUBLIC HEALTH RELEVANCE: Cigarette smoking is the leading preventable cause of morbidity and mortality in the United Sates. Although there are numerous compelling reasons to stop smoking, smoking cessation is difficult, partly because of the unpleasant withdrawal symptoms that individuals experience. These include effects of smoking cessation on mood, sleep, as well as cue-induced craving. The available remedies do not target all aspects of withdrawal. Exercise is clearly an under-utilized intervention and has immense potential benefits for improving smoking cessation. The proposed work will allow us to examine the extent to which exercise, a promising nonpharmacologic behavioral treatment method, can attenuate key symptoms of withdrawal recognized to impede abstinence efforts. A better understanding of these effects will allow us to implement exercise at the time of day that may be more troublesome for the individual attempting to quit. The development of new behavioral methods for attenuating withdrawal symptoms will be directly transferable to smoking cessation treatments aimed at reducing withdrawal symptoms and aiding efforts to avoid relapse after quitting smoking.