High-intensity sports such as running require your body to deliver large amounts of blood and oxygen to your muscles. When you begin running or as you increase the intensity of your runs, you might experience fatigue, a reduction in strength and energy. You can fight this problem in several ways and prevent it from deterring your progress.
Cause of Running Fatigue
Fatigue comes in several forms, explains running coach and author Rick Morris, writing for RunningPlanet.com. The most common, muscle fatigue, occurs when you work your muscles too hard and they can't maintain the energy necessary for the level of activity. Myofibrils, fibers that help your muscles contract and move, don't function as well due to certain changes in the body and the natural muscle damage that occurs during intense physical activity.
Metabolic fatigue most commonly strikes runners who run at least 800 meters or more. The prolonged activity causes your body to produce a variety of metabolic substances that affect how your body uses potassium and other substances necessary to fuel the muscles. It can also increase the acidity of the blood, which can cause burning sensations in the muscles and irritating nerve endings. Running longer distances such as marathons can also cause fatigue in the form of energy depletion. As you run, you burn through your body's store of carbohydrates, a form of energy necessary for physical activity. When your body begins to experience these myriad changes, your central nervous system helps restore your body to balance. This often involves sending signals that slow you down to give your body a chance to recover from depleted energy stores, metabolic imbalances and the like.
Importance of Rest
Once you have completed a run, your body has weakened a bit. To help recover, it undergoes physiological changes to ensure it won't experience the same level of fatigue the next time you engage in similar activity, says exercise physiologist Anna Renderer, writing for Todd Durkin Enterprises. Adequately rest your body to allow for this recovery. Allow for some off-days.
Hydration
Your body requires adequate water to carry out its various processes, including those required to support your muscles during your run. Keep hydrated throughout the day; Renderer explains that hydrating during a run doesn't do much for the damage already inflicted if you were dehydrated before your training session. This doesn't mean you should not drink during a run; you need about 1/2l to 1l fluid for every hour of running. Drink at least half your body weight in ounces of fluid daily.
Dietary Recommendations
Your body uses carbohydrates to create glycogen, the main form of energy for your muscles. The amount your muscles have before a run influences your performance. Depleting these stores too much results in fatigue. Eat plenty of complex carbohydrates that break down slowly and provide a steady flow of energy. Good choices include whole-grain breads, pasta and rice, potatoes and legumes. Renderer recommends pre-race meals consist of 25g protein, 30g fat and 50g to 70g carbohydrates about two hours before the race.
