This is a good read to have healthier DNA:
It’s no secret that sticking to a regular exercise routine is good for your body and
your mind. But until now, scientists haven’t known exactly how working
out changes you physically (besides stronger and more sculpted muscles,
of course). The answer lies in your DNA, report Swedish researchers.
Read more: http://www.shape.com/blogs/working-it-out/endurance-sports-make-your-dna-healthier
I also came across with this related article: https://fleetfeetsports.wordpress.com/2014/08/12/2630/
Kristine Van Pel 