Last week, I talked about basic endurance nutrition, and now we have to wash it down. As much as we all know we have to drink, it sometimes gets hard to figure out what's right and what's a little ways from right. Now, I've been doing this thing for a long time and try to read everything about training for first timers that comes down the pike, but even I get confused as the pendulum swings from one thing to another. I think the bottom line is if you know the basics of hydration (drinking), you won't get yourself into some unnecessary trouble.
What you are about to read has some of the bias that I have developed over the years of doing many, many endurance runs, and I think everything I tell you is a very safe guideline. In a recent book, "Waterlogged" by noted author Dr. Tim Noakes, he graphically debunks decades of tried and true theories of rehydrating. His work also states there is a lesser need for electrolytes and carbohydrates during an endurance event. Now, Dr. Noakes has forgotten a lot more science than I have ever tried to learn, but when you've been running and racing endurance events for over three decades like I have, I have a real problem replacing a foundation that has supported the marathon and ultra community concerning something as simple as hydration (some call it set in my ways!)...so here I go with my views, but I encourage you to read "Waterlogged" and see what feels right to you and then try it out in training.
Dehydration diminishes performance because it thickens the blood, decreases the heart's efficiency, increases the heart rate, and raises the body temperature. After a marathon, even on cool days, a body core temperature of 104 degrees is common. The body is cooled by sweat, and to sweat, a constant supply of water is needed.. most runners can lose 1-2 quarts (2-4 pounds), or more, of sweat per hour. On a very hot day of hard running, I've read a runner can lose up to 4 quarts (9#). Serious symptoms may develop as fluid losses exceed 2% of body weight. In a 150# runner, that's just 3#! A runner must slow their pace 2% for every 1% of body weight loss due to hydration - this could mean the difference of 5 minutes to a 4 hour marathoner! Usually, drinking 6 ounces every 20' will deter hydration, but that can be difficult late in a marathon. I remember at the Marine Corps Marathon one year, I was finding it pretty hard to swallow any more water at about 22 miles. I was about to throw my still half-filled cup to the ground when a well trained Marine yelled at me "You have to drink the whole cup SIR!" I still remember that marine to this day.
Sugar in drinks is beneficial in keeping up your blood sugar, which will spare using your muscle glycogen for fuel. It takes 5-7 minutes to reach the bloodstream once absorbed in the intestines. I recommend you drink sugared drinks (Powerade, Gatorade, etc) in all runs longer than 90'. Don't rely on thirst - it is a poor indicator of fluid loss, and although you can never keep up with your fluid loss, you can minimize the hole you're digging. Dr. Noakes says to drink to thirst, but I honestly believe that by the time you feel the thirst, your fluid deficit is way more than you can ever catch up on.
Research in the last 2 years has reversed the age-old thoughts that caffeine beverages are diuretics (make you pee). They are diuretics to the same degree that plain water is!! You drink water, you need to pee. The same with caffeinated beverages, no more, no less. As a matter of fact, caffeine will help your endurance as it frees fatty acids into the blood stream that can be converted to energy in the muscles and spare some stored glycogen (the carbohydrates you ate last night).
OK, so now we get to drinking too much!! What?? How can that be? Well, since the marathoning boom of the past decade or so, something called Hyponatremia has reared it's ugly head. Hyponatremia means "low blood sodium". This is caused by excessive fluid consumption which lowers the ratio of sodium/water in the blood. Who's most at risk? Well, my 30+ years of marathon coaching and 15 of those as a TNT Coach taught me that walkers and women are the most susceptible. Why? Well, a couple of reasons. Walkers are going to be out there longer and not sweating as much. And, they usually carry their water and drink constantly. As far as women go, they sweat less then men (as much as 30% less), and (here's Coach Al's slant) they listen to their coaches more than men, and if the coach says drink, drink, drink, they'll do that to excess! Men usually will go down their own merry independent paths and drink what they THINK they need - usually too little - but women will do most of the right things. In this case, you definitely don't want to overdo it. Drink to stay hydrated - don't overdrink. If you drink sugared drinks with electrolytes, this will help, but still, don't overdo it! Hyponatremia will make you nauseated, headachy, confused, extremly fatigued, and can cause severe muscle cramps. Much of the time, these symptoms can be confused with dehydration and the well meaning volunteer will make you drink MORE...the one thing you don't need.
I like to carry a water bottle with me - you really hardly notice it if you have one of those handheld ones with a strap you can get at The Trak Shak for about 10-15 bucks. If you'd rather wear a belt with a water bottle, that's fine too, but the point is to stay hydrated. Of course, during your Saturday runs, The Trak Shak Long Run Crew will put out coolers for you every 3 miles or so, and during the actual race, you won't have any problem with frequency, but during those weekday runs (assuming that you're training!), you might tend to be a little more lax. So, what this does is begin you at a deficit the next day, and like a rock rolling downhill, your training can get worse and worse, simply because you're drying yourself out. Just get in the habit of tanking up at each opportunity during the run, and all through the day when you're not running. And with that, you've eliminated one of the major pitfalls of marathons runners.
Good luck with your training and I'll see you on the roads - AL