Background: Taking regular exercise may help people give up smoking by moderating nicotine withdrawal and cravings.
Objectives: To determine whether exercise-based interventions alone or combined with a smoking cessation programme are more effective than a smoking cessation intervention alone.
Search strategy: We searched the Cochrane Tobacco Addiction Group specialized register for studies including the terms 'exercise' or 'physical activity' in July 2004. In August 2004 we searched MEDLINE, EMBASE, PsycINFO, CINAHL, Dissertation Abstracts and SPORTDiscus.
Selection criteria: We included randomized trials which compared an exercise programme alone, or an exercise programme as an adjunct to a cessation programme, with a cessation programme, recruiting smokers or recent quitters, and with a follow up of six months or more.
Data collection and analysis: We extracted data on study characteristics and smoking outcomes. Because of differences in studies we summarized the results narratively, making no attempt at meta-analysis.
Main results: We identified 11 trials, six of which had fewer than 25 people in each treatment arm. They varied in the timing and intensity of the smoking cessation and exercise programmes. Three studies showed significantly higher abstinence rates in a physically active group versus a control group at end of treatment. One of these studies also showed a benefit for exercise versus control on abstinence at both the three month and 12 month follow-up points. One study showed significantly higher abstinence rates for the exercise group versus a control group at the three month follow up but not at the end of treatment or at 12 month follow up. The other studies showed no significant effect for exercise on abstinence.
Authors' conclusions: Only one of the 11 trials offered evidence for exercise aiding smoking cessation. All but one of the other trials were too small to conclude that the intervention was ineffective, or included an exercise intervention which was insufficiently intense to achieve the desired level of exercise. Trials are needed with larger sample sizes, sufficiently intense exercise interventions, equal contact control conditions and measures of exercise adherence.