Leisure-time physical activity and artery lumen diameters: A monozygotic co-twin control study


Corresponding author: Urho M. Kujala, Department of Health Sciences, Sports and Health Laboratory, Rautpohjankatu 8, University of Jyväskylä, P.O. Box 35 (LL), FIN-40014 University of Jyväskylä, Jyväskylä, Finland. Tel: +358 14 260 2171, Fax: +358 14 260 20111, E-mail: urho.m.kujala@jyu.fi


Exercise is thought to increase the diameter of the conduit arteries supplying the muscles involved. We studied the effects of a physically active vs inactive lifestyle on artery diameters in monozygotic (MZ) twin pairs discordant over 30 years for leisure-time physical activity habits. In a population-based co-twin control study design, six middle-aged (50–65 years) same-sex MZ twin pairs with long-term discordance for physical activity were comprehensively identified from the Finnish Twin Cohort (TWINACTIVE study). Discordance was initially defined in 1975 and the same co-twin remained significantly more active during the 32-year follow-up. The main outcomes were arterial lumen diameters measured from maximal intensity projections of contrast-enhanced MR angiography images. Paired differences between active and inactive co-twins were studied. Compared with inactive members, active members of MZ twin pairs had larger diameters for the distal aorta and iliac and femoral arteries (P<0.05 for all comparisons). The mean intrapair differences in the diameters of the arteries in these locations were 19% or larger. No significant differences between active and inactive co-twins (P>0.2 for all comparisons) were found in the dimensions of the carotid arteries. Our genetically controlled study confirms that habitual physical activity during adulthood enlarges arteries in a site-specific manner.