Researchers have discovered evidence that endurance exercise, such as running, swimming, cross-country skiing and cycling, will help you age better than resistance exercise, which involves strength training with weights. Endurance exercise but not resistance exercise can prevent telomeres shortening, or can even lengthen them, according to the first prospective randomized controlled study of the effect of different forms of exercise on this indicator of healthy aging published in the European Heart Journal.
Source: Endurance but not resistance training has anti-aging effects