Training for a long distance race like a half or full marathon can be a stressful goal to achieve no matter how well trained you maybe. The stress of ensuring that you get your miles in for the week, that you stick with your program, ensuring you are performing all the preventive injury exercises and stretches, and maintaining your nutritional intake to maximize every step you make can be a daunting task. Fueling during your run, as it turns out, is possibly one of the most important steps you must do well to ensure a healthy and stress reduced finish.
It is well known that running distance races requires the athlete to refuel with drinks that have simple carbohydrates in them so as not to run out of energy and dehydrate. Many times the thought of using these sports performance drinks stops at the need to maintain a free flow of energy rich blood sugar for the run. While that is very true there is a just as important reason and that is to maintain a healthy immune system during your training and after. In other words that Gatorade the athlete drinks during those long hard runs is also helping support the immune system.
In recent studies on the biochemical cascade of responses the body has to prolonged bouts of exercise such as running, it has been shown that if the athlete does not ingest fluids high in simple carbohydrates that the bodies immune system will become suppressed. The reason is because there is an increase in stress signaling hormones (cortisol for example) released that are responsible for starting the process of breaking down sugar stores in the body. This suppression can last a for a rather long period of time post workout and increase the risk of getting sick and becoming run down as well as longer recovery times.
Studies have also shown that carbo-loading does not affect the this mechanism much. When a person carbo-loads before a race they typically load up 8 hours or more before the run and therefore the carbohydrates are changed over to stored triglycerides. Also, there has been shown a dosing relationship to mitigating the over elevation of stress hormones during prolonged bouts of exercise. The dosing recommendations are about 45 grams of simple carbohydrates per hour with a liter of water or the average amount of simple carbohydrates in a liter of Gatorade. When the normal concentration sports drinks was compared to decreased calorie or low concentration sports drinks, the low calorie sports drinks had minimal effect compared to the normal concentration sports drink that had a positive and significant effect.
Now, this doesn’t mean that more is better and that drinking sports drinks while sitting on the couch is a smart choice. More concentrated simple carbohydrate drinks may cause stomach and bowel issues while running and increased calorie intake while inactive does nothing to help with the immune system. It is all about a happy balance and that is what the research show the normal concentrated sports drinks provide for the body when performing longer bouts of endurance exercise.