Exercise may hold the key to youth, according to a study published, which showed people who keep fit are up to nine years biologically younger than those who do not.
The findings are the first to show how keeping fit affects the aging process in humans.
The study of 2,401 twins found that a sedentary lifestyle raises the risk of a range of problems from heart disease to cancer and appears to play a key role in the aging process.
It all appears to boil down to the length of structures called telomeres - which protect the DNA on the chromosomes - the researchers from King's College London wrote in the Archives of Internal Medicine.
Many studies have shown telomeres get shorter over time, suggesting the cells are ageing or dying. The study, which extracted a DNA sample from their volunteers, found people who exercised more each week had longer telomeres.
Exercise lowers the risk of a range of problems such as heart disease, diabetes and cancer, the researchers said.
"It is not just walking around the block. It is really working up a sweat," Tim Spector, a genetic epidemiologist who led the study, said in a telephone interview.
The study found people who exercised vigorously 3 hours each week had longer telomeres and were biologically 9 years younger than people who did under 15 minutes.
Spector's team, which also adjusted for body weight, smoking, economic status and physical activity at work, also said moderate exercise for 1-1/2 hours each week provided a four-year advantage.
"We are making a logical next step to say people who have shorter telomeres are more prone to age-related diseases," he said. "We think it is because these cells are auto-destructing and the aging process is speeded up."
Studying twins also provided a unique opportunity to gauge the effects of exercise on people with the same or similar genetic make-up and backgrounds, the researchers said.
Questions:
1. If people exercise regularly, up to how many years young biologically could they be?
2. What are telomeres and what do they tell scientists?
3. How much exercise does one need to do in order to have longer telomeres?
Answers:
1.Up to nine years.
2.They protect the DNA around the chromosomes and the longer they are, the more fit and younger the person is.
3.They should do three hours of vigorous exercise each week.
（英语点津 Celene 编辑）
About the broadcaster:
Bernice Chan is a foreign expert at China Daily Website. Originally from Vancouver, Canada, Bernice has written for newspapers and magazines in Hong Kong and most recently worked as a broadcaster for the Canadian Broadcasting Corporation, producing current affairs shows and documentaries.
