Tuesday August 4 2015
Small amounts of exercise can lower the risk of various conditions
Going for a 15-minute walk every day will "make you live longer", reports the Mail Online. It is one of several news outlets to report that small amounts of daily exercise may be enough to increase your chances of living longer.
A study found people aged 60 and over who did just 15 minutes of exercise a day reduced their risk of dying early by 22%, compared with those of a similar age who did no exercise at all.
To stay healthy or improve health, UK guidelines advise all adults do at least 150 minutes of moderate physical activity a week. But many older people fail to meet this target.
The authors of the study found 75 minutes of activity a week appeared to be beneficial. They concluded that lowering the activity target could encourage more adults to take up physical activity.
However, they acknowledge that the more exercise people do, the lower their risk of ill health and early death.
Their findings were based on the results of nine studies involving more than 120,000 people, who were followed up for an average of 10 years.
They found regular exercise reduced the risk of an early death, even if people did less than the recommended amount of 150 minutes. The overall results suggest any physical activity is a good thing, even if recommended targets cannot be met.
But it is premature to say "exercise targets should be cut", as in The Daily Telegraph. The evidence has limitations, especially the fact it was provided by pooling the results of observational studies.
This makes it difficult to know how much the reduced risk of dying is directly the result of how much physical activity we do. Further research is needed to explore the ideal amount of exercise for those aged over 60.
Older people are advised to do 150 minutes a week of moderate aerobic activity. This can be in 10 to 15-minute chunks of activities such as brisk walking, gardening, dancing or swimming. Doing some activity every day is better than doing nothing, and this is true at any age.
Where did the story come from?
The study was carried out by researchers from the University Hospital of Saint-Etienne, the University of Lyon, the University Hospital of Dijon, the University of Burgundy, the Regional Centre for Cancer Prevention, and Jean Monnet University in France, and Geneva University Hospitals in Switzerland.
Funding sources were not described.
The study was published in the peer-reviewed British Journal of Sports Medicine.
This story has been reported widely in the media, providing recommendations and guidelines for better health and improved life expectancy.
What kind of research was this?
This was a systematic review and meta-analysis that aimed to determine whether lower amounts of moderate to vigorous physical activity in those aged 60 and over reduced the risk of dying early. Adults over 60 are currently advised to do 150 minutes of physical activity a week, but it is recognised this may not always be met.
A systematic review is useful for identifying all relevant studies that have examined this question, and combines the results to draw overall conclusions on the direction of the effect. However, the strength of the findings depends on the quality of the trials included.
What did the research involve?
Two literature databases (PubMed and Embase) were searched up to February 2015 for English language prospective cohort studies.
Eligible studies were required to have included people over the age of 60 and examined how the amount of physical activity was related to deaths from any cause during at least three years of follow-up.
What were the basic results?
Nine studies were used, which included a total of 122,417 participants aged 60 years and above (73,745 women and 48,672 men). The average age of participants (from seven studies only) was 72.9 years, and they were followed up for an average of 9.8 years. Six of the studies came from the US, two were from the Pacific region, and one included an Asian population.
Researchers found doing small amounts of physical activity of less than 150 minutes a week reduced the risk of dying early by 22% compared with doing no activity at all (relative Risk [RR] = 0.78, 95% confidence interval [CI] 0.71 to 0.87). A significant difference was found with gender – reduction in mortality was 14% for men and 32% for women.
Following the recommended 150 minutes a week reduced mortality by 28% compared with inactive individuals (RR 0.72, 95% CI 0.65 to 0.80).
It appears the benefit of increased physical activity on reducing mortality grows with increased duration, as participants who exceeded the 150-minute recommendation had 35% reduced risk compared with inactive participants (RR 0.65, 95% CI 0.61 to 0.70).
How did the researchers interpret the results?
The researchers concluded that physical activity "reduces all-cause mortality in older adults". They found the first few minutes of any exercise session were the most beneficial for health.
The researchers acknowledged that the more activity people do, the greater the health benefits. However, they observed health benefits even in those who did only 15 minutes a day.
This systematic review and meta-analysis aimed to investigate whether doing less exercise than the recommended activity levels was still effective in reducing the risk of dying early among adults aged 60 or over.
The study found physical activity even below the recommended amount reduced mortality in this group. However, higher levels of physical activity were associated with an even lower risk of dying early.
This study has strengths in its systematic review methods, the fact it searched the literature for studies published over 20 years that assessed the effects of physical activity, and that it only included studies with good methodological quality.
However, the results are only as reliable as the studies included. Some limitations include the following:
- These were all observational studies. The researchers have used risk figures that have been adjusted for confounders. However, the confounders the nine individual studies have accounted for are not reported and are likely to have varied. Other health and lifestyle factors may influence both the amount of exercise a person takes and their mortality risk. For example, a person with health problems that increase their mortality risk may also be taking less exercise. Similarly, a person taking more exercise may also be following other healthy lifestyle habits, such as not smoking, drinking little alcohol, and eating a healthy, balanced diet. Overall, this makes it difficult to single out the direct effect the amount of physical activity has had on mortality risk.
- The overall sample size was large, but a large proportion of study participants came from two of the nine studies.
- Definitions of bouts of physical activity or "doses" may have differed.
- None of the studies were conducted in the UK, which may limit their usefulness for this population as ethnic, cultural and environmental influences may have an effect.
Many people in the UK are failing to meet the recommended levels of physical activity. This study suggests that even if you can't meet the recommended amount, some exercise is better than none at all.
However, because of the limitations of the review, more research would be needed to look into the ideal exercise level before recommending reducing amounts for older adults.
We know that taking regular exercise has many health benefits, so being as active as possible is always beneficial. Regular exercise can reduce the risk of numerous major illnesses, such as heart disease, stroke, diabetes and cancer.
Exercise may also have beneficial effects on general wellbeing and may have some effect on mental health, such as reducing stress levels and depression.