When it comes to advising how best to manage the medical conditions that are the principal causes of death in the prosperous west, there is absolute clarity from the health profession. Whether it is heart disease, stroke, diabetes or cancers of the breast and the colon, the simple message rings out very clear - more exercise is the one simple thing that almost anyone can do to reduce the risk of becoming a victim of one or other of these conditions.
But although this has been a consistent message for decades now, it still seems to fall, to a great extent on deaf ears. In the UK, the 2012 London Olympics had a significant increase in the proportion of the population engaged in regular activity as one of its major goals. And although the Games were hugely popular, and are widely seen as having delivered a real boost to popular morale, it is still far from clear whether they have lead to a lasting transformation in the attitude to and enthusiasm for exercise.
For some health professionals, this unwillingness to get up from the couch and break a sweat just a little amounts to a global pandemic which has a clear and measurable impact on health - and at the global level it has been characterised as being fatal as is smoking. The World Health Organisation has calculated that over a tenth of deaths from diabetes, breast and colon cancer can be attributed to lack of exercise, along with over 20% of coronary heart disease related deaths.
Looking at the issue from a slightly different perspective, researchers at Brigham and Women's Hospital in Boston found that increasing physical activity by about 10%, could avert some 533,000 deaths a year; increasing it by 25%, might lead to 1.3 million deaths being prevented.
Research has also suggested the line of causation between exercise (or the lack of it) and several major conditions.
For example, exercise can reduce factors such as raised blood pressure, blood sugar and cholesterol thereby cutting the risk of heart disease and diabetes. By keeping the heart itself healthy, physical activity can suppress development of atherosclerotic plaques that may result in blood clots.
With regard to breast cancer, fat reduction resulting from exercise may protect women -- particularly dangerous is belly fat, where the associated metabolic activity may bring about tumour growth in breast tissue. In the case of colon cancer, exercise may mean that digestion is regular and that cancer-causing waste is not able to encourage abnormal growths in the colon.
The unfortunate thing however, is that this evidence and the repeated and insistent message of the huge benefits from exercise is not having the desired impact.
A recent study undertaken by the University of Bristol which analysed the activity of over one million people in the UK made salutary reading. 80% of the sample didn't meet the national target for taking moderate exercise . Of the adults who were able to walk, 8% had not walked for five minutes continuously during a four-week period, while close to half had not walked for leisure for more than 30 minutes . The research revealed 88% hadn't swum, 90% hadn't been to a gym and around 20% of people over the age of 16 did only minimal amounts activity.
Recent research in the United States produced almost identical results regarding participation and also highlighted the extent to which results were skewed by factors such as social class/ educational attainment levels - in both UK and US people who were better educated or in higher income brackets were significantly more likely to exercise at the levels required to meet national standards.
These national standards are the same across the world. The target is that all adults take moderate intensity activity for at least two and a half hours every week - it is also suggested that this is best in a number of sessions, i.e five sessions of about thirty minutes. Moderate intensity activities could include cycling, fast walking and basketball. Alternatively, higher intensity activity such as jogging or fast swimming for 75 minutes each week can bring the same benefits. In addition, activities which strengthen muscles are encouraged twice or more per week for major muscle groups.
The evidence in the UK for an Olympics inspired bounce in physical activity isn't yet wholly clear. Efforts to promote more engagement actually kicked off in advance of the Games and the evidence comparing late 2012 with the picture a year earlier were positive. More recent statistics have suggested that this may not have been sustained much into 2013 but more complete data will become available soon. The major target is the current group of 16-24 year olds with the aim that this group would be inspired to continue sport activities in greater number after they leave school/ college.
The ultimate benefits in terms of national health and expenditure will only emerge as this (hopefully well exercised) group pass into the age bands most susceptible to the benefits of higher activity levels.