Simply standing may blitz exercise when it comes to preserving our DNA. The link between inactive time rather than the exercise time emerges in many studies.

Sitting down for hours-at-a-time shortens telomeres – the protective caps which sit at the end of chromosomes – a 2014 study found. Scientists liken these caps to those plastic tips on the ends of shoelaces.

Short telomeres have been linked to premature ageing, disease and early death in many studies. So how does standing prevent DNA from shortening, and ageing?

People who were frequently on their feet had longer telomeres, which were keeping the genetic code safe from wear and tear, the research found.

The study, published in the British Medical Journal showed that although people who did more exercise tended to be healthier, the key factor was how much time they spent sitting down.  The less time a person spent sitting, the longer their telomeres were.

Formal exercise may be increasing in many countries, but at the same time people spend more time sitting, Professor Mai-Lis Hellenius, from Karolinska University Hospital in Stockholm, says.

“There is growing concern that not only low physical activity but probably also sitting and sedentary behaviour is an important and new health hazard of our time.

“We hypothesise that a reduction in sitting hours is of greater importance than an increase in exercise time for elderly risk individuals,” he says.

The Swedish study was the first one of it’s kind to look at the association between exercise, sedentary time and telomere length. The study was only conducted on a small sample (49 people) – but first studies are usually small. Larger more complex studies are then designed to see if the effect is consistent, so we’d expect to see more studies soon.

Plenty of other studies* have shown associations between sitting time and premature death or poor health outcomes. The health conditions associated with sitting – like  cardiovascular disease or diabetes – have also been associated with shortened telomeres.  But this Swedish study looks to be the first study to start looking into the possible reasons contributing to that.

The physiological reason for decline may be the muscle inactivity time, one study has shown. The exercise people do gets the muscles active, but it’s amount of inactive time between exercise which seems to be the contributing factor to poor health such as worse HDL cholesterol levels, studies show.

The link between inactive time rather than the exercise time was also found in the Swedish telomere study. Sitting doesn’t work the hamstrings or thighs, whereas standing does cause a baseline amount of work by those muscles, which are some of the largest in the body, so it might be that base level of activity and work that occurs which is a protective effect. Another study has shown similar effects of breaking up sitting time for cardiovascular risk.

The Swedish study was looking at telomere length specifically in blood cells in older people, so it’s likely we’ll see from further studies on the effect in other cell types, on other age groups.

There’s no doubt we’ll see more about the link between exercise, sedentary time and telomere length soon,  so stay tuned, and standing!

More info:

* Studies showing associations between sitting time and poor health outcomes. study 1, study 2, study 3, study 4),

“If you imagine the end of your shoelace, think of the shoelace as the chromosome which is where the genetic information is carried. If you don’t protect the ends of the shoelaces they’ll fray away, and by analogy the telomere is a little bit like the tip at the end of the shoelace, it protects the shoelace, or in this case the genetic material from fraying away from the ends.”  Professor Elizabeth Blackburn.