Did you know DNA affects your athletic power ability?
Not just blood pressure: the AGT gene and muscle power
Whoever coined the phrase “you can’t teach an old dog new tricks” probably wasn’t thinking about genes. The more scientists study our genes, the more they become convinced that we’ve barely scratched the surface on unraveling the mysteries in our DNA. For one, our physiology seems to be almost fool-proof, with often more than one genetic pathway available to achieve the same end result, highlighted by the finding that only about 2,000 (~10%) human genes may be absolutely necessary for survival. And then there are genes that control many different traits at the same time (think of hair colour or eye colour), as well as genes that make more than one protein at a time.
As if this wasn’t confusing enough, sometimes our bodies appear to work in mysterious ways, like the AGT gene. For years it appeared that angiotensinogen, the protein product of the AGT gene, was involved in controlling blood pressure, immunity and inflammation. Now we also know that inheriting a specific version of AGT can also give you an advantage in sports that require strength and power.
Traditionally, angiotensinogen (Agt) was considered to be a passive substrate of the renin-angiotensin system that controls our blood pressure. Agt is present constantly in our blood, but when the kidneys notice a drop in blood pressure or salt levels, it releases a hormone called renin, which converts Agt to angiotensin I. Angiotensin I is further processed into angiotensin II by the action of the Ace enzyme. Ace is another protein also linked to athletic performance. Angiotensin II is responsible for several physiological effects, including increasing salt reabsorption in the kidneys and narrowing of the arteries. Narrow blood vessels restrict the movement of blood, thus increase blood pressure. Some of us naturally have higher Agt levels due to the presence of a genetic variant of AGT called rs699. This variant elevates blood pressure, and increases the risk of heart disease. This same variant is also linked to conditions such as type II diabetes and cancer, suggesting that the role of Agt is far from simple.
The link between AGT genetic variation and athletic performance is a perfect example of how many other characteristics the AGT gene can also influence. One variant, called rs699 C, is linked to higher Agt levels and increased risk of high blood pressure, but is also associated with an athletic power advantage. Power athletes such as jumpers, throwers and sprinters are more likely to have the rs699 C variant, compared to endurance athletes and non-athletes. One study has shown that inheriting two copies of the rs699 C allele increases the odds of becoming a power athlete by 68%. Additionally, it appears that people with the rs699 C allele respond better to training targeted to improve explosive power. But, why a genetic variant that increases blood pressure also makes you better at sports that require power isn’t really obvious. There is some evidence that it may have to do with angiotensin II promoting muscle growth. However, more research is necessary to substantiate this claim.
Linking AGT to athletic performance isn’t exactly teaching an old dog a new trick. It’s actually more like uncovering a trick the dog possessed that we were unaware of. Regardless, it’s a story worth following, especially if you have the version of AGT associated with high blood pressure. The odds are it will reveal just how you can ameliorate your risk of heart attack by choosing the right type of exercise.