Even short physical activity has benefits: US health authorities

The Straits Times by SALMA KHALIK

Just moving more can help you stay healthy, sleep better and even be smarter, according to the latest American guidelines on physical activities released last week.

More information on the benefits of greater physical activity has emerged since the previous guidelines a decade back.

One of the biggest changes is that there is now evidence to show "any amount of physical activity has some health benefits". Previously, the recommendation was that at least 10 minutes are needed for activity to count.

There are both immediate and long-term cumulative benefits to exercise. Just a single bout can reduce anxiety and blood pressure, improve quality of sleep and insulin sensitivity.

Regular exercise reduces the risk of eight types of cancers - bladder, breast, colon, endometrium, oesophagus, kidney, stomach and lung - and decreases pain for people suffering from osteoarthritis, as well as improves cognition for those with dementia.

Keeping children aged three to five physically active throughout the day enhances their growth and development. They need at least three hours of active play ranging from light to vigorous intensity daily.

The latest guidelines from the United States Department of Health and Human Services were released at the American Heart Association's Scientific Sessions in Chicago last Monday, following extensive study of available literature over the past two years.

The guidelines say adolescents aged six to 17 need 60 minutes of moderate to vigorous activity that makes their hearts beat faster on a daily basis. They also need activities to make their muscles and bones strong. These activities include climbing playground equipment, playing basketball or skipping, and they need to do this at least three times a week.

New evidence also shows that exercise improves the cognitive function of children aged six to 13.

For adults, the guidelines say: "For substantial health benefits, adults should do at least 150 to 300 minutes a week of moderate intensity, or 75 to 150 minutes a week of vigorous intensity aerobic physical activity."

This should preferably be spread throughout the week. They also need to do muscle-strengthening exercise at least twice a week.

Older adults need multi-component activities that include balance training, aerobic and muscle strengthening. It recommends activities such as dancing, yoga, taiji, gardening or sports.

By exercising more, they are "less likely to fall, and if they do fall, the risk of injury is lower".

For people with chronic medical conditions, new evidence shows that exercising "reduced risk of all cause-and disease-specific mortality, improved function and improved quality of life".

Even those who are frail can benefit from exercise as it can improve their physical function, and help with daily activities such as bathing or moving from the bed to the chair.

Pregnant women can exercise without increasing pregnancy risks. Exercising reduces risk of gestational diabetes, which puts women at higher risk of getting diabetes in future, as well as symptoms of post-partum depression.

The guidelines add that there is "some evidence" that exercise may reduce pregnancy complications such as pre-eclampsia and the need for caesarean delivery, as well as reduce the length of labour.

The US government says insufficient physical activity costs the nation US$117 billion (S$161 billion) in annual healthcare costs and is responsible for 10 per cent of premature deaths in the US.

Mr Zee Yoong Kang, chief executive officer of the Health Promotion Board, said: "HPB has been encouraging a wide range of exercise types. These include improving cardiovascular fitness, building strength, balance and agility, improving muscle mass and preventing bone mass loss."

He added that, over time, the board plans to adjust local guidelines to cater to the needs of different age groups.