Even with regular exercise, the genetic makeup of about 20 percent of people means they won't see much improvement in their physical endurance, according to a new study.
An international team of scientists examined the DNA of 473 people and had them complete 20 weeks of endurance training. About 15 percent to 20 percent of the participants had much smaller endurance improvements than expected, USA Today reported.
A combination of about 30 genes predict "to a significant extent" a person's aerobic response to endurance training, said the scientists. The study appears in the Journal of Applied Physiology.
The researchers noted that their findings about endurance don't mean that some people shouldn't bother exercising.
Physical activity offers benefits in many other areas, including heart rate, cholesterol levels, blood pressure and insulin metabolism, said study co-author Tuomo Rankinen, a scientist in the human genomics laboratory at the Pennington Biomedical Research Center in Baton Rouge, USA Today reported.