A researcher from Brigham Young University in Provo, UT, found that running for 30 or 40 minutes every day for 5 days each week can reduce the shortening of telomeres and decrease cellular aging by 9 years.

Telomeres are the protective caps at the ends of chromosomes, which are thread-like structures in cells that hold our DNA. They are often compared with the plastic tips at the end of shoelaces, as they stop the ends of chromosomes from fraying and sticking to other chromosomes.

Telomeres are considered a marker of biological age. As we get older, telomere length shortens. When telomeres become too short, they are no longer able to protect chromosomes, which can cause cells to stop functioning and die.

Poor lifestyle factors, such as lack of exercise, can also contribute to telomere shortening by causing oxidative stress, which is the inability of the body to offset the cell damage caused by free radicals.

The new study - conducted by Prof. Larry Tucker of the Department of Exercise Sciences at Brigham - demonstrates just how important physical activity is for protecting against cellular aging.

The findings were recently published in the journal Preventative Medicine.

'A little exercise won't cut it' when it comes to slowing biological aging

For his study, Prof. Tucker analyzed the data of 5,823 adults who were a part of the 1999-2002 National Health and Nutrition Examination Survey.

The researcher looked at the telomere length of each participant. In addition, he looked at subjects' participation in 62 physical activities over a 30-day period, using this information to calculate their physical activity levels.

Compared with participants who were sedentary, those who were highly active were found to have telomere lengths representing a biological age of 9 years less, and a biological age of 7 years less compared with those who were moderately active.

Thirty minutes of jogging daily for 5 days per week was deemed highly active for women, while 40 minutes of jogging every day for 5 days each week was considered highly active for men.

Prof. Tucker says that he was surprised to discover that the telomere length between sedentary participants and those who were moderately active were not significantly different. This indicates that in order to protect against cellular aging, high levels of physical activity are best.

"If you want to see a real difference in slowing your biological aging, it appears that a little exercise won't cut it. You have to work out regularly at high levels.We know that regular physical activity helps to reduce mortality and prolong life, and now we know part of that advantage may be due to the preservation of telomeres." Prof. Larry Tucker