How much do we know about diet and exercise in older age?


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One of the drawbacks to getting older is that it gets harder to stay in shape. The reality is that nature dictates muscle loss in our later years. Although some studies have found that diet and exercise can offset this problem, new research from the University of Southampton suggests the current evidence about what works and what doesn't is inconsistent.


Running up that hill

No matter how well we might look after ourselves when we're younger, on average, we start to lose muscle mass — eventually around 30 to 50 percent of it — between the ages of 40 and 80. Naturally, this results in a decrease in strength and means a reduced ability to carry out everyday tasks. This condition — called sarcopenia — is linked to frailty and poorer health in older people and is relatively common. According to a report from the National Institutes of Health (NIH) in 2010: "it is estimated that 5–13 percent of elderly people aged 60–70 years are affected by sarcopenia. The numbers increase to 11–50 percent for those aged 80 or above." Unsurprisingly, the associated health care costs are substantial.

To combat the condition, the traditional advice is to combine exercise training with diet supplementation. Although this approach has shown results in preventing muscle loss in some studies, little is certain about the combined effects of training with supplements, particularly in older people. This is partly because measuring the extent and effects of sarcopenia itself is quite hard. The NIH report concludes that "it is difficult to estimate the prevalence of sarcopenia, mostly because of practical difficulties in assessing muscle mass. Many different methodologies have been used over the last 20 years, and new techniques are still being introduced."


Deeper understanding

For the new study, the team at Southampton decided that what was needed was a clearer picture. In their research, published in the journal Clinical Interventions in Aging, the scientists reviewed thousands of combined diet and exercise training trials in men and women who were over 65 years old. In total, almost 5,000 scientific articles were screened. Their findings show that results differ across studies and so suggest that more research is needed. "Although some studies have found enhanced effects of exercise training when combined with diet supplementation," says Professor Sian Robinson who led the review, "our review shows that current evidence is incomplete and inconsistent. Further research to determine the benefits of supplementation and exercise training for older people is therefore needed."

As the world population ages, this kind of research is of growing importance, not just for personal health care but increasingly for local, national and international planning of social care. Avan Aihie Sayer, Professor of Geriatric Medicine who oversaw the review, comments: "Sarcopenia is now recognised as a major clinical problem for older people. Gaining insights into the effects of lifestyle on losses of muscle mass and strength will be essential for the development of future public health strategies to promote better health in later life."


Don't give up

Fundamental changes occur as we get older, all of which contribute to sarcopenia. Among these are the changes in our hormone levels and protein requirements as well as the fact that we tend to lead more sedentary lifestyles. The Centers for Disease Control and Prevention (CDC) advises on the effectiveness of strengthening exercises as we get older. They can, the CDC say, help in the fight against arthritis, diabetes, osteoporosis, obesity, back pain, depression, heart disease and poor sleep. "Exercise can slow the physiological aging clock," they say. "While aerobic exercise, such as walking, jogging, or swimming, has many excellent health benefits — it maintains the heart and lungs and increases cardiovascular fitness and endurance — it does not make your muscles strong. Strength training does. Studies have shown that lifting weights two or three times a week increases strength by building muscle mass and bone density."

The new research shows that there is still a way to go before we can fully understand the best strategy for combining nutrition with exercise as we get older. However, knowing what we don't know is, presumably, half the battle. Yet, Robinson argues, a strong overview is not just a useful tool for understanding the effectiveness of such an approach, it is, in light of its developing social significance, a first concern.  "Poor diets and being physically inactive are common in older age. Understanding the benefits of maintaining sufficient levels of physical activity and diet quality to prevent sarcopenia is therefore a priority," she says. So whatever you do, stay active!