Aerobic exercise is a physical activity that exercises the body’s large muscles rhythmically and repetitively, eg walking, cycling, and swimming. Aerobic exercise increases the heart rate and your body’s oxygen consumption and reduces the risk of contracting heart disease, diabetes, high blood pressure and high cholesterol.
The official recommendations, based largely on surveys of participants’ reports of exercise activity, are that 150–300 minutes of moderate (eg walking) to vigorous (eg running, swimming) physical exercise or 75–150 minutes of vigorous physical activity (VPA) per week is necessary to achieve optimum health results. However, this is a substantial time commitment — an hour a day if you are using your local gym. Many people find it very difficult to maintain this commitment and quickly drop out of aerobic exercise programmes.
However, recent studies have demonstrated that cumulative intermittent short bouts (two minutes) of VPA, easily integrated even into the busiest schedule, very significantly boosts health. This work is summarised by Chuck Dinerstein, and published in the American Council on Science and Health.
The link between exercise and general health has been appreciated since ancient times: “In order for man to succeed in life, God provided two means, education and physical activity. Lack of activity destroys the good condition of every human being, while movement and methodical physical exercise can save it and preserve it” — Plato.
Epidemiological evidence showing the relationship between physical activity levels and mortality was reported in the classic studies of Jeremy Morris and Ralph Paffenbarger from the 1950s on. Morris showed the incidence of coronary heart disease and sudden cardiac death was lower in London bus conductors compared with bus drivers. The difference was attributed to the greater physical activity levels of conductors. Paffenbarger and colleagues during the 1970s demonstrated an inverse relationship between physical activity and cardiac disease and all-cause mortality.
The beneficial health effects of intermittent short bouts of VPA were most recently reported in detail by M Ahmadi and others in the European Heart Journal. The authors concluded that VPAs totalling 15-20 minutes per week, each VPA lasting two minutes, is associated with a 16 to 40 per cent lower mortality rate, with further decreases in mortality rate attainable up to 50 to 57 minutes VPA per week. 103,000 adults aged 40–69 from the UK Biobank participated in the study. The researchers drew on lifestyle characteristics/incidence and mortality data from cancer and cardiovascular disease over six years and used accelerometer data to accurately measure physical activity.
How can such a marked reduction (threefold) in the amount of time necessary to reduce the risk of cardiovascular disease and cancer by an equivalent amount to that attainable by following the official standard guidelines of 75-150 minutes of vigorous exercise per week be accomplished by following the latest VPA recommendations? Was the research underpinning the standard guidelines wrong?
Dinerstein thinks not, proposing that the discrepancy is much more likely explained by the different ways physical activity was measured in the different studies. The standard guidelines rely heavily on measurements of activity based on self-reported exercise. These reports could well be uncertain because of memory and could be affected by personal bias about how strenuous the exercise was and/or even by a desire to look good. Accelerometer data, used in this recent study, is much more accurate in measuring exertions.
These latest results on the positive health effects of very short intermittent bouts of vigorous exercise must, of course, be confirmed by other researchers in this field. But, if these reports hold up, and I think they will, this discovery represents the most exciting and important health news announced for a very long time. It will mean that nobody has any excuse any more not to exercise sufficiently to dramatically improve their good health prospects.
It seems amazing to me that these greatly reduced health risks are attainable through such modest amounts of exercise accrued in short bursts throughout the week. Every mobile person could easily incorporate these short exercise bursts into their daily routines — simply take a brisk walk for several minutes or rapidly climb two flights of stairs, for example. I now take several daily brisk five-minute walks in my garden.
This latest research deserves the widest publicity. These new VPA recommendations, so easily achievable by almost everybody, promise an enormous boon to improved public health.
- William Reville is an emeritus professor of biochemistry at UCC