Marathons and Hydration,pt.2

Hold on there! I know what you're thinking, pt.2 on marathons and hydration? Yes, what follows is info that you are probably unaware of, info that could potentially improve performance and your ability to recover from the marathon and other long races. Again, we have data from Dr. David Costill, an exercise physiologist who has done more testing and research on runners than any other person in this field in the U.S. It is said that when running or racing long distances what you drink should be more of a concern than what you eat. Think about this, you burn around 100 calories per mile and it takes 35 miles to lose a pound of flesh while you can lose a pound of fluid in two miles,even faster if it's hot. Costill wrote: "When a man loses 2% or more of body weight by sweating, his ability to perform prolonged exhaustive exercise is impaired." I've known many runners who have foolishly refused to properly hydrate during a race because they thought it would disturb their "rhythm",or, it was too awkward to drink while on the run. Something else you may be aware of but for those who aren't, Dr Costill found in his testing that our thirst is not an accurate guide to our fluid needs. He also discovered that a runner can't fill his fluid needs during the course of a run or race. Consequently,we have to make it a priority to properly hydrate during the longer run and races. Dr. Costill wrote, " in laboratory tests that required about eight pounds of sweat loss,we found that thirst was temporarily satisfied by as little as one pound of water. Total replacement of body weight may take several days unless the runner forces himself to drink more than is desired." Is it any wonder that Costill believes a daily weight check is a more accurate indicator of dehydration than thirst? Perhaps the one thing that might cause the most concern in his findings, "chronic dehydration can drastically damage a runner's endurance capacity by lowering his tolerance to fatigue, reducing his ability to sweat,elevating his rectal temperature and increasing the stress on his circulatory system." From reading the above, there is no question that in the past I have been negligent at times of not properly rehydrating as well as not consuming enough fluid during long races. How 'bout you?