Study highlights link between exercise and smoking habits
People who are physically active as teenagers are less likely to become smokers than inactive teenagers, according to new research from a team of Finnish and American researchers. The work, which was partly funded by the EU, is published in the journal Addiction. It has long been known that people who exercise regularly are less likely to smoke than those who are relatively inactive. Most people ascribe this fact to the family, arguing that children whose parents encourage physical activity are more likely to adopt a healthy lifestyle themselves. In this latest study, scientists observed almost 2,000 pairs of twins, asking them about exercise levels and smoking habits in their late teens and then again in their early to mid twenties. They found that physically inactive adolescents were five times more likely to be smokers by the age of 24 than physically active teenagers. To test whether the differences could be due to upbringing, the scientists then compared twins who showed different levels of activity as teenagers. They found that physically inactive twins were three times more likely to take up smoking than their physically active brothers and sisters. As the twins shared the same upbringing, the difference cannot be put down to different family circumstances, the researchers note. 'Persistent physical activity seems to be an important factor in the causal pathway in selecting and maintaining non-smoking behaviour,' they write. The scientists put forward a number of mechanisms by which physical activity could influence smoking habits. One idea is that physically active children may be keen to improve and maintain their fitness, and know that smoking will interfere with this goal. Furthermore, these youngsters will probably seek friends with similar interests. Exercise is also known to have a positive effect on other factors that protect against smoking, such as perceived ability to cope and self esteem, the scientists note. Finally, they point to other research which indicates that smoking and exercise could stimulate the same parts of the central nervous system. In a related editorial, Paul Aveyard of the University of Birmingham and Michael Ussher of the University of London welcome the new findings, and call for trials to test their usefulness in discouraging young people from smoking. 'Given the strength of these findings, we feel that there is a strong case for trials to examine whether physical activity interventions reduce smoking initiation in adolescents and young adults,' they write. 'These studies will need to identify and recruit actively those who are most susceptible to starting smoking, including the sedentary, those with mood disturbance and those already experimenting with addictive substances.' EU funding for the study came from the Fifth Framework Programme GenomEUtwin project.
Countries
Finland, United States