Over the years you’ve likely realized you’re better at some activities more than others. Perhaps there’s a type of sport that comes natural to you. Maybe you’re taller than most people, which helps in a number of activities. Or, like me, you might be better suited for going for long walks, runs or bike rides. This could be due to your genes, or DNA. And with DNA, we’ve always been told you can’t change it. But more research is showing us how exercise can affect your DNA.
A Primer on DNA
Deoxyribonucleic acid (or commonly known as DNA) contains our genetic, or hereditary material. It’s like an old family recipe passed on for generations. And we get a copy from each of our biological parents. Only in this case, DNA is a recipe for how our body works. With it, our body knows how to make the many proteins we need to function. From building-blocks of muscle, to hormones that regulate our metabolism, without DNA we wouldn’t exist.
Each of us has somewhere between 20-30 000 genes, with the exact number a matter of vigorous debate. But needless to say, we have a lot. And the number and type of genes are mostly the same from person to person. However, within these genes, there’s variation. This variation is extremely small <0.001% (and smaller between those who are related). But it’s these differences that account for why two people aren’t the same.
While DNA may differ from person to person, within the same person, the same DNA is found in almost every cell in your body. Even still, not all genes are used in each cell. Or all the time. Genes are regulated within the cell depending on their purpose. Similar to lights in a house, in which you can turn them on and off as you need them. For example, the genes active in your eyes may differ from those in your heart.
Exercise Turns on Your Genes
When you exercise, you’re putting your body under physical stress. It adapts to that stress by becoming stronger and more efficient. This can lead to a number of changes, some of which include increasing the number of red blood cells, building muscle and/or making it easier to use fats as fuel.
One way exercise works is to upregulate your genes. Upregulate means a gene is being used to create the protein it’s coded for. And exercise can be the reason a gene is upregulated. After people exercised for up to two weeks, a protein involved in the breakdown of fat (lipoprotein lipase) increased.
The effects are also known to happen in short bouts of exercise. As little as three 20 second bursts of high intensity activities, like an exercise snack, may be enough to turn on genes helpful to the working muscles. But you don’t need to be doing all-out sprints to affect your genes. Even two minutes of light walking after sitting was enough to upregulate genes related to using fat for energy.
Make Your DNA Look Younger
The human body contains trillions of cells, and each day billions undergo the process of dividing to replenish lost cells. Every time a cell divides, DNA is copied so the two new cells have their own exact copy. This process is extremely efficient, but sometimes mistakes happen. As we age, more mistakes accumulate leading to DNA damage. Many of these mistakes have no effect, but some increase one’s chance of getting diseases such as cancer. However, people who exercise have less DNA damage than non-exercisers at the same age.
Exercise also has other anti-ageing effects on DNA. When not in use, DNA is tightly packed into chromosomes. These chromosomes are capped off by telomeres meant to protect the chromosomes from breaking down. Every time a cell divides your telomeres shorten. And as we age, our telomeres get shorter. It’s believed the length of telomeres may be related to one’s life expectancy.
However, regular exercise is associated with longer telomeres. Compared to non-exercisers, exercise an hour per day was similar to preventing nine years of telomere ageing. But it’s not just preventing shortening that exercise can help. After six months of moderate activity in older adults, telomeres increased in length, even while they shortened in the non-exercise group.
Exercise can Change the Tags on Your DNA
But even if you have a certain gene, it may not matter if it is modified in a way that keeps it turned off. This occurs when the gene becomes methylated. Methylation is a chemical tag on a gene that’s like someone putting their hand on a light switch to prevent it from being turned on. These tags are in all of us and can also be inherited (this area of research is called epigenetics). However, as we get older, the more DNA tags we have.
Exercise may prevent these tags from forming. Older men who were lifelong exercises, had fewer tags on their genes related to metabolism and muscle function, compared to men who were inactive. Similar findings have been reported in women and the benefit of exercise is greater with age. It was thought these chemical tags were irreversible; once a gene had them, they couldn’t come off. This doesn’t seem to be the case as a single bout of exercise has been shown to remove chemical tags. And the more intense the exercise, the more likely the tags were removed.
As these chemical tags can also be inherited, exercise in parents may impact the genes of their children. Women who are active during pregnancy have children who tend to have improved motor control as infants and lower risk for obesity and heart disease, even into adulthood. It’s believed some of these changes are due to fewer chemical tags inherited from the mother to the child. Indeed, women who were more active during and before pregnancy had children with fewer chemical tags on a gene associated with increased weight.
While it’s still true you can’t change your DNA, exercise can keep your genes primed and ready to go, as well as keep them looking younger.
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