Importance of Hydration

Instead of recommending that athletes drink as much as possible during exercise, they are now recommending that athletes only consume the amount of fluid they have lost due to perspiration. According to the USATF guidelines, the best way to to this is to drink only when thirsty during exercise, instead of following the conventional advice to “stay ahead of your thirst”.

Athletes who follow this advice can prevent dehydration while at the same time lower their risk of suffering from hyponatremia (low sodium). Athletes who follow the recommendation to consume 150% of the fluid they lose during exercise could cause a dangerous drop in an athlete’s sodium level. According to the new USATF guidelines hyponatremia is a potentially fatal condition that is seen more and more often as long-distance runners follow the advice they have been given to over-hydrate themselves. Hyponatremia most often occurs in exercise lasting four hours or longer and results primarily from consuming excessive fluids which is exacerbated by not replacing sodium losses. Severe cases of may involve grand mal seizures, increased intracranial pressure, pulmonary edema (fluid in the lungs), respiratory arrest and even death.

Many scientists now view hyponatremia as just as much of a threat to runners as heat illness and dehydration, and major papers distributed by the International Association of Athletics Federations (IAAF) and USATF have described these potential problems and how to avoid them.

Other Medical Issues

Other Medical Conditions
As runners have learned the importance of hydration during long distance events, dehydration has become a less prevalent condition. Medical crews at marathon finish lines now are dealing more with hyperthermia (heat illness), postural hypotension (pooling of blood in the legs), hyponatremia, and the normal injuries that are common among marathon runners such as blisters and muscle injuries.

Hyperthermia
Hyperthermia can occur regardless of hydration levels or the distance of a race. In fact, shorter races can pose more of a threat due to the faster pace per mile, which causes greater heat production. An adequately hydrated runner who is running too fast or pushing herself too hard, especially in hot and humid conditions, can fall victim to hyperthermia. It is therefore important that athletes adjust their pace to take into consideration race conditions, slowing their pace as heat and humidity rises, regardless of how much they may be drinking.

Postural Hypotension
Postural hypotension is experienced when a runner suddenly stops, most commonly at the finish line. With blood pooling in the legs, there is inadequate blood supply to the rest of the body and the runner feels faint and can fall down. This had been thought of as demonstrating dehydration, so the response from medical teams was to rehydrate these runners. Now, medical personnel can identify this problem correctly and treat it specifically. Treatment requires raising the runner’s feet above the head for 3-4 minutes for full recovery. Runners can avoid postural hypotension by keeping the legs moving, even with light walking or moderate knee flexing when they otherwise would stand still at or immediately after the finish or at other locations along the race course.

More Information
In April of 2003 a paper called “Proper Hydration for Distance Running – Identifying Individual Fluid Needs”, was published by Douglas Casa, Ph.D., ATC, FACSM, of the University of Connecticut, is and was issued by USA Track & Field. April 2003 Paper in PDF Format

In March of 2003 the International Marathon Medical Directors Association and the Association of International Marathons and Road Races issued an “Advisory Statement on Guidelines for Fluid Replacement During Marathon Running” written by Tim Noakes MBChB, MD, FACSM of the University of Cape Town, South Africa; and David E. Martin, Ph.D. FACSM, of Georgia State University. It was published in the International Association of Athletics Federations (IAAF) “New Studies in Athletics”, March 2002 on pages 15-24.

as posted on www.skatelog.com