This is the first study to examine the effect of yoga on smoking cessation. Our results provide preliminary evidence that yoga may be an effective adjunctive treatment for smoking cessation in women. Specifically, yoga appears to enhance the effects of CBT on short-term smoking cessation outcomes. While the sample size precluded formal mediation analysis, results of secondary analyses suggest that the positive effects of yoga on smoking outcomes may occur via reduction of negative symptoms associated with quitting smoking, decreasing stress and cigarette cravings, and improving mood and perception of quality of life.
Numerous studies have shown that stress is a strong predictor of both inability to quit smoking and smoking relapse.72–74
Other research has shown significant reduction in stress and negative mood following even a few weeks of yoga practice.75–77
In addition to making quitting smoking uncomfortable and difficult, perceived stress, negative affect, and withdrawal symptoms themselves have all been shown to increase an individual's risk for relapse to smoking. Relapse within the first week of quitting is preceded by a marked increase in withdrawal symptoms, including craving for cigarettes, distress, and reductions in positive affect.49
Perceived stress and negative activated affect have also been shown to predict time to relapse among recent exsmokers.46,48,78
Thus, providing smokers with methods of coping with stress, such as a yoga program, may improve their ability to quit and remain exsmokers.
These findings are important because they suggest that yoga is a viable treatment adjunct for women who would like to quit smoking without the use of medications. Since this study did not include the use of medications, the relative effect of yoga versus medications on nicotine withdrawal and cigarette craving is not established. Additional work would be needed not only to compare those effects but also to determine whether the effect of yoga and medications might be redundant or have an additive or synergistic effect when used together.
Vinyasa yoga, which incorporates features of breathing exercises (pranayama
) and meditative components in addition to moderate-to-vigorous intensity exercise, may be especially appealing relative to traditional aerobic exercise. For example, in addition to producing improvements in cardiopulmonary functioning, the practice of yoga has been linked to improvements in affect, reductions in stress and anxiety, increases in self-efficacy, and improvements in overall well-being.53–56
These benefits may result from the unique aspects of yoga, including meditative approaches to focus attention and deliberate regulation of breathing during pranayama
exercises. Finally, yoga is intended to be a lifelong practice often sustained for years once begun by practitioners thereby having the potential to continue to reinforce quitting smoking once formal smoking treatment ends.
This pilot study had a number of strengths. First, in terms of study design, we used random assignment to study conditions, a contact control comparison condition, objective indicators of smoking cessation, and an ITT approach to analysis. Second, participants demonstrated good treatment adherence and retention rates, with no differential adherence to treatment or withdrawal from the study. Third, abstinence rates at follow-up were strong compared with previous smoking cessation studies of this kind, although these outcomes must be considered preliminary given the small sample size used in this pilot. Fourth, the observed differences between yoga and control conditions on variables hypothesized as mechanisms of action suggest that the treatment operated through the intended mechanisms and was not due to nonspecific effects. Fifth, our sample was representative for our recruitment area and was similar in age, demographic characteristics, and smoking behaviors to samples of women in our previous studies,58,59
suggesting good generalizability.
The study also had a number of limitations, many of which might be addressed in future research. First, because it is not possible to blind participants to study condition, expectancy effects cannot be completely ruled out. Second, the intervention period was only 8 weeks in duration. This allowed us to demonstrate proof of concept; however, a longer treatment period may be needed to demonstrate sustained efficacy. The superior results obtained in the yoga intervention appear to weaken over time during follow-up. An intervention protocol that encouraged more home-practice of yoga or eased the transition from active treatment/studio practice to practice on one's own may have reduced this attrition in efficacy. Third, the sample size was small, thus limiting power to detect significant differences between conditions during the follow-up period. A slow recruitment process necessitated randomization by cohort, which produced unequal groups. Finally, our intervention targeted generally healthy adult women smokers. It is unclear what the ultimate reach of the yoga intervention might be for less healthy populations or whether it would offer additional benefits to smokers who are not sedentary.