A Brief Stroll Helps Smokers Walk Away from Cigarettes

EXETER, England, March 13 -- A short walk may help smokers curb tobacco cravings and other withdrawal symptoms, according to a meta-analysis.

A single session of even low intensity exercise significantly improved craving scores and doubled or tripled the time between cigarettes for smokers, said Adrian H. Taylor, Ph.D., of the University of Exeter here, and colleagues, in the April issue of the journal Addiction.

The immediate effects of exercise compare well to sugar or nicotine-replacement therapy, Dr. Taylor and colleagues said.

Although the 14 studies included in their systematic review included predominately smokers who were not attempting to quit, the results suggest that exercise may aid those who are, they said.

"Relatively small doses of exercise should be recommended as an aid to managing cigarette cravings and withdrawal symptoms," the researchers wrote. "A relatively small dose of exercise in which most people can conveniently engage appears to be sufficient."

Among the studies reviewed, 12 compared exercise to a passive control while two studies compared only exercise of differing intensities. Two were unpublished, and two were published only as abstracts.

Most of the studies were small, and all but one involved current smokers temporarily abstaining for the experiment. The 1,369 total participants typically had an inactive or low-activity lifestyle.

The results were:

• All 12 studies comparing exercise with a control found a positive effect on at least one key outcome measure of cravings, withdrawal symptoms and smoking behavior.
• Nine of 10 studies comparing exercise with a control found a significant reduction on cravings with an effect size ranging from 0.29 for five minutes of seated isometric exercise to 4.6 for a brisk one-mile walk (mean overall effect size 1.1 at 10 minutes after exercise).
• Eight of the nine studies looking at withdrawal symptoms found a fairly consistent, significant reduction in at least two measures such as stress, anxiety, tension, poor concentration, irritability, and restlessness.
• Three of four studies looking at mood found improvements with exercise.
• Four studies reported a significant increase in net time to next cigarette by 24 (effect size 1.0), 8, 57 (effect size 1.2) and 35 minutes (effect size 0.85), respectively.

The one study to include actual quitters during an 11-week cessation intervention found that exercise reduced negative mood, nicotine withdrawal and cigarette cravings in all weeks after the quit date.

While temporary abstinence among smokers is commonly used for these experiments, the severity of symptoms among these individuals may not be the same as those experienced by quitters, Dr. Taylor and colleagues wrote.

Among three studies looking at exercise intensity, one found significantly lower cravings with high-intensity cycling for five minutes versus low-intensity cycling but the others were underpowered or found no difference in outcomes.

"Given the relatively small number of studies and the heterogeneous doses of exercise across those studies, it is probably premature to consider the impact of methodology on the findings," the researchers wrote.

"However, it would appear that the effects of exercise are similar following brief or longer periods of abstinence, and for moderate or higher levels of baseline cravings," they added.

The reduction in strength of desire to smoke ranged from 0.7 points on the seven-point scale for five minutes of isometric exercise to 4.6 for a one-mile walk whereas a previous study of glucose versus placebo reported a 1.0 reduction. Also, exercise showed an effect on cravings during and after activity whereas a rigorous study showed a 10-minute delay in the effects of nicotine gum.

"The magnitude of the reduction in cravings is encouraging and comparable with, or in many cases exceeding, the acute response to glucose and oral nicotine replacement therapy," the authors wrote.

A previous systematic review published in The Cochrane Library in 2005, found evidence from only one trial that exercise assists smokers quit long term compared to smoking cessation support alone.

Exercise is often recommended as an aid to smoking cessation, which Dr. Taylor and colleagues noted has been predominately to limit weight gain and the fear of weight gain.

They concluded that exercise may also be important in managing withdrawal symptoms as well.

Distraction was unlikely a primary mechanism since the effects lasted for up to 50 minutes, they said. Stress reduction and psychobiological mechanisms may be more likely explanations, they added.

Further research into the mechanisms involved and in the setting of actual quit attempts will be needed since "this line of research is in its infancy," the researchers wrote.