A gene linked to exercise-induced heart growth has been identified by Spanish researchers.

They found the hearts of athletes who had two copies of the D (deletion) form of the angiotensin-converting enzyme (ACE) gene grew more in response to exercise than the hearts of other athletes with 1 D allele and one I (insertion) allele.

The study, which appears in the August 6 issue of the Journal of the American College of Cardiology, may give new insight to scientists studying heart enlargement in certain diseases.

The findings indicate there's an association between this gene and heart growth, not that the gene itself is responsible for controlling the rate of heart growth. This fits in with other researcher linking variations of the ACE gene to heart enlargement.

The study included 61 male athletes, aged 25 to 40, with similar fitness training backgrounds. Ultrasound was used to measure the size of their hearts. The researchers found the DD genotype was associated with a higher left ventricular mass index than the ID genotype.