Monday, March 12, 2007
How do I determine how much and what to drink while training for a marathon?
Hi Gary, i"m a first timer doing the marathon (Rotorua) having trouble with the fluids, how much is too much, how much is too little? On my longer training days would a camel back be the answer as I run in the country, nowhere to get water on the way, my last long run [2hrs] came back feeling sick, light headed , not great, obviously not enough fluid, water or sports drink? your advice would be grateful.
Gary Moller comments:
The first thing to do is to have a method of feedback to determine if, in fact you are getting dehydrated and to determine your needs.
Weigh yourself immediately before you run and immediately after. What you have lost in weight is water. So, if you lost a Kg then that equates to 1 liter of water. Drink 1 1/2 liters over the next hour or so to make it up. Weighing regularly before and after runs gives you an idea of how much you are losing on a typical run (depending on factors like, temperature, humidity and pace, of course!) and therefore how much to drink during a run.
Learn to listen to your body signals. The weighing will help you to become sensitive to your body. Thirst is very useful - as long as you know how to listen carefully and respond early. Most people have no idea how to listen and therefore must resort to rote formulas for fluid consumption which I detest.
If you are suffering nausea and light-headedness after a long run, it could be worthwhile to purchase a blood pressure and heart rate monitor and take regular readings to determine what is happening to heart rate and blood pressure before and after a run. If you do so, then write to me with the reults to assist interpretation. Read these giudelines here for a good explanation about blood pressure.
When we lived in Putaruru all of our long Sunday runs with our Dad were in the forests of Tokoroa and the Mamaku. It was 2-3 hours before breakfast with no fluids. While this was tough I can assure you that I am still alive and in excellent health! My kidneys are fine. It seems the body does adapt if given the right nudging and time. In my sister Lorraine's case, being able to run very fast for 2.5 hours in heat and humidity with little more than a cup of water along the way was essential for winning an Olympic marathon medal in stinking hot Barcelona.
However, getting deathly dehydrated is probably not necessary in training for most and drinking a liter or so of water along the way is a good idea especially if the runner is a heavy sweater and the conditions warm.
I am not keen on carrying water when running. The risk of leg injury is high enough as it is and adding a Kg or two more onto the legs is adding to that risk. It is better to plan the course so that there is a drink station, like a tap or bottle along the way. This could be done by doing a couple of laps of a course from where the car is parked, or planting a bottle of water at the 1/2 way mark before you commence the run.
I do not recommend using a sports drink or similar when training. Water is best. You are using your long runs to stress your body's energy reserves and swigging sweet liquid is not going to allow this to happen. The sports drinks should be reserved for the actual race - not in training. However; if you are going to be running at pace, then you must ensure that you can tolerate sweet electrolyte drinks. Practice drinking your sports drink during some of your short, fast runs and see if it stays down. I have found that water is best when running; whereas sports drinks are fine for sports like cycling where there is less problems with jiggling and jostling of the gut. I prefer to make my own using Balance Elite but any of the commercial powders are fine. I have even taken to adding a teaspoon of Balance Glutamine to the mix to assist stamina and recovery and it seems to work. Read my e-book about training for a marathon which has plenty of training information.
When mixing your drinks, err on the dilute side. If the weather is hot and humid, then you need more liquid and less of the sugary stuff. If it is cold and wet, then you need less water and more of the sugars. If you are running very fast, then you may only tolerate a little fluid in your gut which is why having a good tolerance of dehydration is important for elite runners; whereas when running very slow, or walking, you should have no trouble drinking and your main risk might be death from drinking too much.
During the marathon, there are more than enough drink stations by the organisers so there is no need to carry your own. Run light. Drink early and listen to your body signals and respond accordingly.