Research suggests that as many as one in every 10 deaths worldwide are the result of lazy, inactive lifestyles - almost as many as are caused by smoking.
In a study published in the Lancet medical journal, researchers reveal how people's growing apathy towards physical movement is a serious factor when it comes to global health.
While smoking and alcohol consumption are widely known to cause health problems, the researchers warn that many people believe they are healthy simply because they avoid such vices, and are slipping into sedentary lifestyles that can have similarly severe implications.
The authors claim that around one in 10 deaths from major diseases such as diabetes, breast and colon cancer, and heart disease are attributable to insufficient exercise - around 5.3 million deaths a year in total.
The researchers also estimate that up to 1.3 million deaths would be prevented if physical activity rose by 25 percent worldwide.
To avoid the health problems highlighted in the study, the authors recommend that people should attempt to spend at least 150 minutes a week performing moderate physical activity.
Dr I-Min Lee, who co-authored the report from her Boston laboratory, said: "This summer, we will admire the breathtaking feats of athletes competing in the 2012 Olympics Games. Although only the smallest fraction of the population will attain these heights, the overwhelming majority of us are able to be physically active at very modest levels - for example 15-30 minutes a day of brisk walking - which bring substantial health benefits."