Texas Hydration for Cyclists
Texas Hot
There is hot and then there is Texas Hot. A lot of blogs about hydration are for places where it is not nearly as hot as it is in Texas. People in Texas and other places where it gets really hot need the best possible preparation for the heat.
Pre-hydrating
Pre-hydrating is useful to a point. The goal is to be fully hydrated but beyond that, hydrating can be detrimental because it removes useful electrolytes. How can you tell if you’re hydrated? The easiest way is the color of your pee. “Clear and copious” was my mantra when I coached. If you really want to know the details, you can google it and find a color chart but it’s pretty simple: The darker your urine, the more dehydrated you are. If you pee every couple of hours and it is clear, you are good. If it is 6 or more hours between needing to pee and it is dark and smelly, you are dehydrated.
Morning Routine
It does not matter how much “pre-hydrating” you do; you will always be slightly dehydrated when you wake up in the morning. It is useful to drink some water when you first wake up. If you get to the start at 7AM and you only had to pee the first thing in the AM, you are probably starting a little dehydrated, no matter how much you “pre-hydrated” on Thurs-Friday. We are not camels. I typically lose about 1.5 lbs or about 12–13 oz overnight.
Alcohol
Alcohol will dehydrate you. Alcohol replaces water in your body. If you go to bed on Friday with alcohol in your system, you will wake up that much more dehydrated on Saturday. Alcohol and hot weather do not mix well! Sorry!!!
Pre-ride hydration
The best, most useful time to pre-hydrate is immediately before you start a ride. Drinking an entire bottle immediately before a ride (like less than 5 minutes before the start.) It will fill your stomach with water and cause your stomach to release water at a maximal rate. If you drink it, say, 30 minutes or more before, you will have to pee before the ride starts (or more annoyingly, just after the start!) and it will not do you any good.
Ride hydration and sweat rate
It is possible to calculate your sweat rate and you usually need 1 and a half to two times as much water to replace that sweat. It is also possible to put yourself in danger by overhydrating on a ride. The max recommended amount of water to drink when exercising to the max is 1200 mg water/hour. That’s about 42 oz. Since I sweat a lot, I target about 35 oz/hour for a ride. That’s easier to do if you start like I do with a 24 oz bottle immediately before a ride. Drinking too much causes hyponatremia (water intoxication) and, again, it can be fatal.
Salt
Salt is essential. Yes, sweat contains potassium and other “electrolytes” but our body’s reserves of potassium is so high, you cannot become potassium deficient through exercise. Salt is crucial. Taking in fluid without also taking in adequate amounts of salt dilutes the bloodstream, so that the concentration of salt in the blood is lower than that in brain cells. This causes fluid to move from the low-salt blood into the high-salt brain causing the brain to swell which can cause seizures and death. On average, you should expect to lose at least 500mg of salt an hour if you are exercising hard, unless you are (like me!) someone who sweats a lot and then you should plan on losing up to 1,000mg/hour. That’s a lot. None of the sports drinks have enough salt because if they added enough to be useful, it would not taste as good and people would not buy it. Look at the salt in your sports drink (even if it is just Pepsi!) and add what is necessary. 1 teaspoon of salt is 2,000 mg. Nuum tablets have 360 mg. Eating whole salt tablets is not the best idea because they make a significant percentage of people nauseous. You really don’t want to throw up on a hot ride! If you can eat solids in the heat (I have a really hard time with solids in the heat), eating a salty snack is useful.
Heart rate & Heat Stroke
One of the most common ways to know that you are getting seriously dehydrated is that your perceived effort and heart rate will go up. If your heart rate starts going up and does not come down as normal when stopped, beware!
The crucial “heat index” is the temperature of your brain and your core temperature. In the real heat, I carry 3 bottles: 2 to drink from and one to pour water on my head. It helps.
When heat stroke begins to affect your brain, your head will start to hurt, you may hear a ringing in your ears, feel dizzy and have difficulty seeing. Then you will end up unconscious. Your temperature is now over 106 and your brain is being cooked just like the colorless portion of an egg that turns white when it hits a hot griddle.
When a person passes out from heat stroke, get medical help immediately. Any delay in cooling can kill the person, and you may need an expert to help decide if the person has passed out from heat stroke or a heart attack.
Carry the victim rapidly into the shade and place him on his back with his head down and feet up so blood can circulate to his brain. Once it has been established that the person is not having a heart attack, he or she can be cooled by pouring on any liquids you can find. Evaporation of any liquid cools.
How Badly am I Dehydrated?
If you want to know how dehydrated you are after a ride, you need to weigh yourself immediately before and after a ride. Water weighs almost exactly a pint a pound. Again, it will require that you drink (over time!) almost twice what you lose in a ride to become fully hydrated again. My personal max was 7 pounds and it took me a couple of days to get back to normal. Some in the club have lost a lot more. Most people will not feel good if they lose that much water, just saying!
Where did all that come from?
http://www.drmirkin.com/fitness/salt-the-only-mineral-you-need-to-replace-during-exercise.html
http://www.drmirkin.com/fitness/2152.html (Water pre hydrating is useful)
http://www.drmirkin.com/public/ezine103011.html (lose 4000 mg of salt)
http://www.drmirkin.com/public/ezine022005.html (salt brain)
http://www.drmirkin.com/fitness/1198.html (heat stroke)
https://www.teamusa.org/USA-Triathlon/News/Blogs/Fuel-Station/2018/May/07/Hydration-for-Endurance-Athletes-Training-in-the-Heat (training in heat)
http://www.drmirkin.com/public/ezine082105.html (Hyponatremia — too much water)