Risk of death increased or decreased depending on the level of participants' physical activity.
Excessive alcohol use leads to around 88,000 deaths each year in the United States and shortens the life of those that die by almost 30 years.
Drinking too much alcohol has immediate effects that increase the risk of many harmful health conditions and are usually as a result of binge drinking.
Over time, excessive alcohol use can lead to the development of chronic diseases, such as heart disease and stroke and several types of cancer - including breast cancer, liver cancer, and colorectal cancer. High alcohol intake has been linked to a heightened risk of death from all causes.
Some research indicates that alcohol consumption and physical activity may be associated with chronic diseases through shared common biological pathways that act in opposite directions. For example, the biological pathways through which cancer formation begins (carcinogenesis) are similar to those by which physical activity may prevent cancer.
Researchers aimed to determine whether physical activity reduces the risk of death from all causes, and from cancer and cardiovascular diseases induced by alcohol intake.
Data examined was from responses to nationally representative health surveys in England and Scotland - each linked to cause-specific mortality - for the years 1994, 1998, 1999, 2003, 2004, and 2006.
The survey asked questions on daily, weekly, and monthly alcohol consumption and frequency of physical activity among individuals age 40 or above.
Associate Prof. Emmanuel Stamatakis, of the Charles Perkins Centre at the University of Sydney in New South Wales, Australia, and team identified six sex-specific categories of alcohol intake from the surveys including "never drunk," "ex-drinkers," "occasional drinkers" (no alcohol in the past week) within United Kingdom government guidelines, "hazardous drinking," and "harmful drinking."
One quarter of study participants were classed as inactive
Occasional drinkers were classified as having an intake of up to 14 units for women and 21 units for men, hazardous drinkers up to 35 units for women and 49 units for men, and harmful drinkers more than 35 and 49 units, respectively.
Of the people who responded to the surveys, 36,370 adults between the ages of 40-102 years were included in the study. A total of 14.6 percent (5,307) of survey responders who reported no alcohol intake were made up of lifelong abstainers from the "never drunk" category and former drinkers from the "ex-drinkers" category.
Some 13.3 percent of respondents exceeded the then recommended weekly maximum, while of the occasional drinkers, the alcohol intake averaged at just over six units.
Physical activity - including walking for any purpose and light, moderate, and vigorous sport or exercise that took place in the 4 weeks before the survey - was measured in Metabolic Equivalent of Task (MET) minutes. MET expresses the amount of energy, or calories, expended per minute of physical activity.
Weekly physical activity was divided into three categories: inactive (less than 7.5 MET/hour), active at the lower end of the recommended scale (more than 7.5 MET/hour), and active at the upper end (more than 15 MET/hour). On average, the weekly tally was found to be 8.8 MET/hour.
Of the people who answered the physical activity questions, approximately 1 in 4 (27.5 percent) people did not partake in physical activity of any kind.
Around 61 percent of individuals did not achieve 7.5 MET/hour a week, which corresponds to the 150 minutes of moderate-intensity physical activity needed to meet recommended guidelines.
Around 39 percent of respondents reached the lower recommended weekly target, and around 23.3 percent achieved physical activity at the higher end of the scale. During follow-up, there were a total of 5,735 deaths.
Physical activity level drives increase or decrease in death risk
Study results indicate a direct association between alcohol consumption and death from all causes and cancer.
When compared with lifelong non-drinkers, ex-drinkers and hazardous drinkers had a greater risk of death from all causes. As the number of weekly units increased, so did the risk of death from cancer, even when alcohol unit levels fell within the recommended guidelines.
Although researchers determined that occasional drinking had a marginally lower risk of death from all causes and cardiovascular diseases, the lower levels had no protective effects over death from cancer. This finding suggested a "J-shaped curve," explain the researchers.
The risk of death increased or decreased depending on the level of physical activity. People were more susceptible to die from cancer as alcohol intake rose from within the recommended limits up to harmful levels and if they failed to meet the minimum recommended levels of 7.5 MET/hour.
However, the risk was reduced or canceled out in those survey participants who were from the minimum recommended physical activity level group upward.
While this study is observational and cannot prove cause and effect, the team points out that physical activity - even at the minimum recommended weekly level of 7.5 MET an hour - may be able to promote health and limit some of the damaging effects of alcohol.
"The protective effects of physical activity were evident from a level of meeting the minimal public health recommendations of physical activity," the authors write.
"Our results provide an additional argument for the role of physical activity as a means to promote the health of the population even in the presence of other less healthy behaviors."
Stamatakis and co-authors conclude by saying that the public health relevance of their results is further highlighted by the alcohol consumption guidelines being recently updated by the U.K. Chief Medical Officer after finding that the risk of death from cancer begins from relatively low levels of alcohol consumption.