Heat and Hydration
With temperatures in the 80's yesterday at the Promise Land 50k, now is a good time to discuss hydration and electrolyte replacement while running ultramarathons. A lot has changed in the past few years and some of the advice we are being offered is now different from in the past. Some of the new science has been done in response to deaths due to over-hydration in marathons.
We have been told that to wait until we were thirsty to drink is too late, rather we should drink according to a set schedule. Another thing we have been told is to consume a lot of sodium in the form of salt tablets on a regular basis, also according to a set schedule. Not every source has been repeating this advice, fortunately.
There are several links below that anyone considering an ultra in the summer should read. Some of the material is provocative, challenging the validity of research sponsored by Gatorade. (It turns out that much of the research on hydration for athletes has been funded by Gatorade.) To sum up the new research in one sentence is: trust your body and drink to thirst; also salt to taste. Read on...
The best place to start is The Science of Sport, which has published five posts on exercise and dehydration. The main points I take away from these posts is that over-hydration is a real problem, and that your body does a much better job of regulating the sodium concentration of your bloodstream than anyone suspected before recent research.
The next place to look is the Overhydration Website, which covers one topic: Hyponatremia. This website has a concensus statement of advice on hydration and salt replacement.
I ran ultras for three years drinking too much water and ingesting too much salt. It was common for me to gain weight during an ultra, which was completely due to excess salt ingestion. My hands would swell, I had to remove my wedding ring before each race. Even today I still read race reports where so-and-so took an S! cap every hour. Yesterday at Promise Land I was out on the course for more than an hour longer than I had hoped (due to another problem I won't go into here), but I didn't take any S! caps and I only carried one water bottle. I followed the post-hyponatremia advice and drank to thirst. I ate salty foods at the aid stations, and used two Nuun tablets. I had no swelling at all (wore my ring during the race and it was loose all day), and I ended the race down three pounds, which is what you would expect from 50k++ and 7000 feet of climbing. (Weight loss is due to the depletion of energy stores in the muscles). The consensus statement says that no one should finish an endurance event weighing more than when he or she started.
Follow your own advice and learn the needs of your own body, but make sure you are aware of the need for drinking the right amount of fluids and ingesting the right amount of sodium. For any race, the best tool to determine if you are over or under-hydrated during a race is a scale. Unfortunately a scale is not always practical. Try any change in your hydration or sodium regimen in training before changing your race procedures.
We have been told that to wait until we were thirsty to drink is too late, rather we should drink according to a set schedule. Another thing we have been told is to consume a lot of sodium in the form of salt tablets on a regular basis, also according to a set schedule. Not every source has been repeating this advice, fortunately.
There are several links below that anyone considering an ultra in the summer should read. Some of the material is provocative, challenging the validity of research sponsored by Gatorade. (It turns out that much of the research on hydration for athletes has been funded by Gatorade.) To sum up the new research in one sentence is: trust your body and drink to thirst; also salt to taste. Read on...
The best place to start is The Science of Sport, which has published five posts on exercise and dehydration. The main points I take away from these posts is that over-hydration is a real problem, and that your body does a much better job of regulating the sodium concentration of your bloodstream than anyone suspected before recent research.
The next place to look is the Overhydration Website, which covers one topic: Hyponatremia. This website has a concensus statement of advice on hydration and salt replacement.
I ran ultras for three years drinking too much water and ingesting too much salt. It was common for me to gain weight during an ultra, which was completely due to excess salt ingestion. My hands would swell, I had to remove my wedding ring before each race. Even today I still read race reports where so-and-so took an S! cap every hour. Yesterday at Promise Land I was out on the course for more than an hour longer than I had hoped (due to another problem I won't go into here), but I didn't take any S! caps and I only carried one water bottle. I followed the post-hyponatremia advice and drank to thirst. I ate salty foods at the aid stations, and used two Nuun tablets. I had no swelling at all (wore my ring during the race and it was loose all day), and I ended the race down three pounds, which is what you would expect from 50k++ and 7000 feet of climbing. (Weight loss is due to the depletion of energy stores in the muscles). The consensus statement says that no one should finish an endurance event weighing more than when he or she started.
Follow your own advice and learn the needs of your own body, but make sure you are aware of the need for drinking the right amount of fluids and ingesting the right amount of sodium. For any race, the best tool to determine if you are over or under-hydrated during a race is a scale. Unfortunately a scale is not always practical. Try any change in your hydration or sodium regimen in training before changing your race procedures.