Researchers led by Elizabeth Blackburn, PhD, winner of the 2009 Nobel Prize in Physiology or Medicine for telomere-related discoveries, measured the telomeres in white blood cells of 5,309 participants, ages 20 to 65, with no history of diabetes or heart attacks. They found that people who drink sugared sodas daily have shorter telomeres than those who drink fruit juices or artificially sweetened drinks
The huge number of mitochondria in dogs' muscles explains why sled dogs can run more than 100 miles a day, at sub-8-minute-mile pace for weeks on end, while humans could not possibly run as long or as fast and recover from such abuse of their muscles.
If you are going to exercise at a relaxed pace for a few hours, you rarely need to eat or drink unless you feel hungry or thirsty. However, if you are going to compete in sports or exercise intensely for more than 70 minutes, you should take sugar just before you start and while you exercise.