Last Sunday I had the second big training run, and I planned to experiment with hydrating and fueling to see if I could rid the problem of nausea in the late miles that I experienced last year and a little bit on this year’s first 20 miler.
Earlier in the week I was reading some articles about hydrating during long runs. Usually there are two schools of advice. The first is to drink frequently along the way to avoid dehydration because if you wait until you are thirsty, you have waited too long. The second thought is to drink to thirst, meaning, only drink when you are thirsty because not doing this could lead to dilution of salts in the bloodstream and put you at risk for hypoatremia (swelling of the brain). I have always followed the former method, so on this next 20 miler, I decided to only drink to thirst.
I also read about fueling – how often and how much fuel is needed for a long distance run, like a marathon? Last year while preparing got Chicago, I had only one 20+ mile run because of injuries in training. During Chicago I got bad nausea around mile 23, and I struggled for a couple miles after that. Most of what I read about fueling suggests taking in 200-300 calories per hour, starting at the beginning. This also assumes you have carbo-loaded properly leading up to the race. I definitely wasn’t doing this. Carbo loading tops off our glycogen reserves, which would last most about 15 miles – enough to get you through a half marathon but not 26.2 miles. Not only this, but going out to fast or running faster than normal will burn through that glycogen, so it needs to be balanced. But adding about 200 calories every hour will help slow down that glycogen consumption. We’ve all heard of “hitting the wall” around mile 20. This is usually caused by glycogen depletion and lack of energy available to muscles. Then our bodies must convert fat to glucose, something useful for our muscles. This itself is energetically expensive, so meanwhile, you feel tired and out of energy. This is what happened to me at mile 23 at Chicago.
So on this 20 mile run, I started fueling 25 minutes into the run and every 25 minutes after. I used PowerGel with just a small amount of water to dilute the gel. Later I took in water as I learned what real thirst is. I chose PowerGel because it contains 2 types of sugar that have 2 different pathways in our body and can be used simultaneously.
So how was it? Excellent. I ran the first half in about 1:45 and the second half was about the same, finishing at 3 hrs 29 minutes. The best part was that I felt great at the end Instead of struggling. In fact my fastest mile was 9:31 , mile 20. So maybe I have found something that works for me. The proper fuel and the right way to hydrate. What works for me might not work for you. Everyone is different, so experiment if you also have nausea difficulty or feel exhausted at the end of your training runs.