Exercise Vs. Genetics: Which Has A Greater Effect on Health?
Adult identical twins with different exercise routines have significantly different bodies and brains, despite having identical genetic features, according to a new study.
“The main aim of the present study (FITFATTWIN) was to investigate how physical activity level is associated with body composition, glucose homeostasis, and brain morphology in young adult male monozygotic twin pairs discordant for physical activity,” said the study authors.
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For the study, Finnish researchers assessed questionnaires reporting on the medical health of sets of twins (taken at age 16 and retaken every few years following) in the FinnTwin16 database. Researchers looked for twins whose exercise habits significantly diverged after leaving their childhood homes.
Once researchers found 10 pairs of male identical twins—one twin exercised regularly, while the other did not due to family pressures or work demands—researchers evaluated the twins in the lab to measure their body compositions, endurance capacities, and insulin sensitivity to highlight their overall metabolic health and fitness levels.
After comparing results, researchers discovered that the active twins’ brain scans showed significantly heightened areas of grey matter (P <0.001) in areas that impact coordination and motor control compared to the sedentary twins.
The study also showed that the sedentary twins had higher body fat content, lower endurance capacities, and signs of insulin resistance (a precursor to metabolic syndromes), despite the fact that both active and sedentary twins shared a similar diet.
The investigators noted that while exercise habits had only been divergent for a few years, the participants’ bodies and brains rapidly impacted their health in different ways.
“The findings may contribute to later reduced risk of type 2 diabetes and mobility limitations,” said the authors of the study.
The complete study is published in the March issue of Medicine and Science in Sports and Exercise.
-Michelle Canales Butcher
Reference:
Rottensteiner M, Leskinen T, Niskanen E. Physical activity, fitness, glucose homeostasis, and brain morphology in twins. Med Sci Sports Exerc. 2014 March [epub ahead of print] doi: 10.1249/MSS.0000000000000437.