This article is very interesting, showing the amazing effects of weekly xc skiing aswell as some other important tips
The study, performed by Researchers at Ball State University in Indiana, shows that skiers were about 40% fitter than the non skiers,20 %faster at double-poling, 17% faster at skating, 14% faster at classic style skiing, and 12% faster while running.
This intrigued me into possibly Xc skiing more often and maybe taking it up as a hobby. THis quote from the article certainly convinced me to give it a go. "Good genes can help you live a long life, but if you want to fully enjoy those later years, go skiing"