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. Last Updated: 07/27/2016

ACE Enzyme Makes for Genetically Better Athlete

There are, it turns out, natural-born athletes. Researchers have discovered a genetic reason that may explain why some people are more adept at sports than the rest of us.

In a brief article published Wednesday in the journal Nature, a research team in Britain reported some people have a slightly different form of an enzyme, and the difference helps muscles be more efficient after vigorous training. In other words, they can squeeze a little more oomph from any given amount of energy.

The enzyme - fittingly called ACE - is known as the "angiotensin-converting enzyme" that is found in human skeletal muscle. Through the genetic lottery, some people inherit a slightly different version of the gene that makes ACE. This longer version of the enzyme is less active, and that seems to enhance physical performance.

"The presence of this ACE allele [version of the gene] confers an enhanced mechanical efficiency in trained muscle," researcher Hugh Montgomery and eight co-workers wrote. They can't say why there is a difference, but suggest it may be linked to improved energy use by tiny bodies called mitochondria, the "energy factories" found inside cells.

Montgomery and his colleagues at the British Heart Foundation Center for Cardiovascular Genetics, in London, based their report on a study of 58 British army recruits doing workouts on exercise bikes during an 11-week period. Each soldier's oxygen use was measured during exercise periods to calculate the energy used to generate muscular motion.

Before the training, the muscular efficiency of the recruits was not correlated with whether they carried the long or short version of the enzyme. But the response to training was strongly dependent on which type of enzyme was present in each person.

At the end of their training regimen, Montgomery and his colleagues said, the bikers born with the slow-acting form of the enzyme were using energy more efficiently compared to those with the ordinary enzyme. By the end of training, those with the long form had improved more than 8 percent. The others even saw a slight decrease in efficiency.

"We do not know how the II genotype [the longer enzyme] helps to improve the mechanical efficiency of trained muscle," the researchers said. "But it may be related to an increase in slow-twitch rather than fast-twitch muscle fibers." The two types of muscle fibers, as indicated by their names, contract at different speeds and play some role in endurance.

In addition to the implications for athletic performance, Montgomery and his colleagues think the difference may also be important to the health of the cardiovascular system. If less energy is needed to do a given amount of work, then stress and strain on the heart would be reduced.

"Congestive heart failure, for example, interferes with the delivery of oxygen and metabolic substrates [nutrients] to the whole body, so improved skeletal muscle mechanical efficiency would be beneficial," the research team proposed.