Regular exercise offsets the harms of alcohol including cancer and heart disease, research shows.It found that adults who drink regularly but do an hour's physical activity a day are no more likely to die than teetotallers.
Experts say exercise counteracts many of the harmful processes which occur in the body after drinking alcohol. These include inflammation of the cells and a rise in certain hormone levels, which trigger cancer and other illnesses
‘Physical activity should be encouraged as a means to promote the health of the population even in the presence of other less healthy behaviors like alcohol drinking.’
The new research by University College London and the University of Sydney found that drinking - even within guidelines - raises the risk of early death by at least 16% and cancer by 47%. It also highlighted the health benefits of exercise.
But 150 minutes a week of moderate activity completely canceled out the impact of death from all causes while lowering the cancer risk by 36%. It also cut the chance of dying from hazardous drinking by more than half.
The scientists believe that drinking alcohol and exercising share a similar metabolic pathway in the body but operate in opposing directions. While alcohol forces the liver to abandon its work getting rid of fatty acids, exercise does the reverse, using up fat as fuel. So while drinking is damaging to health, exercise is protective.
The study published in the British Journal of Sports Medicine,
looked at six health surveys involving 36,370 people in England and Scotland carried out between 1994 and 2006 which included questions about drinking and activity levels among those aged over 40. During the study period nearly 6,000 people died.
Around 85% drank occasionally or often and this included 13% who exceeded the recommended safe limit of 14 units a week.
The researchers found that the chance of developing cancer and dying early rose steadily as people consumed more alcohol.
But when physical activity was factored in, the risk of death was canceled out or even lowered as people undertook more exercise even up to hazardous levels, the equivalent of 35 units for a woman and 49 for a man.
While hazardous drinking usually raises the risk of early death by 20% and cancer death by 52 %, moderate exercise lowered the risks to 9% and 18% respectively. Doubling the level of exercise per week to 5 hours completely among adults who exceeded the safe drinking levels made them less susceptible to deaths.
The study, although observational, concluded that meeting the current physical activity public health recommendations (two and a half hours) offsets some of the cancer and all-cause mortality risk associated with alcohol drinking.
Professor Matt Field, from the UK Centre for Tobacco and Alcohol Studies at the University of Liverpool said 'This is a rigorous piece of research with some clear conclusions. The relationship between drinking alcohol to excess and increased risk of death is significantly weaker in people who are physically active. Therefore, it appears that physical activity may partially offset some of the harmful effects of drinking, particularly alcohol-attributable cancers."
People who are already ill may be less active than those who are healthy and the researchers were unable to look at the role of different types of drinking.
But Professor Kevin McConway, an expert in statistics at the The Open University, said adults should not just assume they could drink as much as they wanted as long as they exercised. "Maybe the people who exercised a lot tended to have different diets, or different drinking patterns, and maybe that is what changed the risk pattern and not the exercise at all."he added.
However, no firm conclusions could be drawn from the study and some of the findings may be down to chance or other factors aside from exercise.