Nutrition and Hydration for Distance Runners
By Chaim Wizman
If you are training properly for a marathon or a half marathon, you are, by definition, pushing your body hard. Your body is a precision machine that, like a car, must be properly fueled in order to obtain optimal performance. The role of proper nutrition in your program is no less important to your sucess on race day than your actual training program. In this article, I will attempt to provide a brief overview of what you should be doing to stay properly fueled and hydrated.
Hydration: Staying well hydrated is absolutely critical for the distance runner. Not only will dehydration negatively affect your performance during a run but it well also impede your recovery afterwards since fluids remove waste products and bring nutrients to tissues for repair. When you sweat, your blood volume decreases and therefore less oxygen rich blood reaches your working muscles to produce energy aerobically. This, in turn, forces you to slow down. When you run in hot and humid weather, this effect is magnified because the body sends more blood to the skin to remove heat, making even less available to the muscles. So how do you know if you are drinking enough? Don't rely on feeling thirsty to cue you about the need to drink. The body's thirst mechanism lags behind the actual process of dehydration. Many marathoners become chronically dehydrated without knowing it by virtue of a small daily deficit in th eamount of fluids they take in versus the amount they expend. The result is fatigue, irritability, loss of motivation and often injury. In fact, research has shown that often that feeling that we interpret as hunger is actually thirst and can be alleviated simply by drinking more water regularly. It goes without saying that runners who lose a lot of fluid during exercise need to drink far more than the average person in order to compensate for this additional fluid loss. It is useful to weigh yourself on an accurate digital scale just before a long run and then immediately afterwards in order to guage your fluid loss. Your objective should be to replenish that weight loss with fluids within four hours of your workout. So without making you neurotic about consuming a specific amount per day, I will make the following suggestions. Drink two full cups of water upon waking up in the morning and two cups of water before each meal. This will also help you avoid overeating. In addition, keep a sports bottle filled with water at your desk and drain it several times a day. If you find it hard to stomach water, you can lightly flavor it with a sweetened concentrate but go easy on the syrup as it is easy to consume large amounts of empty calories from sweet drinks if you are not careful. Sports drink such as Isostar, Isotone and Powerade are excellent choices during runs of more than one hour and immediately thereafter because they provide carbohdydrates that are readily usable energy and are absorbed as quickly as water. They also contain sodium to enhance glucose and water absorbtion and improve fluid retention.
Nutrition: Most of the energy you use during exercise is provided by carbohydrates with a smaller percentage provided by fats. Since the body can only store 2000-2500 calories of carbohydrate in the form of glycogen, you need to continuously replenish your glycogen stores after a workout. Incidentally, the faster you run, the higher the proportion of carbohydrates that you use. This fact led to the now discredited theory that if you want to burn fat, you should run slower. Carbohydrates are a more efficient energy source than fat because breaking down fat requires more oxygen per calorie. Therefore, you can't run as fast by just burning fats. The upshot of all this science is that, if you want to marathon train, you are going to have to adopt a high-carb diet. If you took up marathoning to lose weight (you will, I guarantee it) and are dieting with an Atkins type low carb diet, forget about it. You will be like a car running on empty. Instead, choose a diet high in complex carbohydrates. Some excellent food choices are rice, pasta, bread, sweet potatoes, pancakes, bagels, potatoes, corn, raisins and cereal.
The timing of your meals is also important. I always used to skip breakfast until I became a serious runner. We have all heard the mantra about how breakfast is the most important meal of the day and we have all ignored it. Well, don't. My standard breakfast during marathon training is 2 bowls of cereal such as cornflakes or cheerios, a banana, a cup of orange juice and two glasses of water. Rather than eat three large meals a day, it is good to graze throughout the day with healthy, high carb snacks such as fruit, pretzels, rice cakes and granola bars. If your mileage is high and your weight is under control, treat yourself to some good ice cream or cake a couple of times per week. You deserve it. One of the best aspects of marathon training is that you can get away with indulging occassionally without guilt. Also make sure that you have at least one good source of protein such as chicken, fish, eggs or meat every day. Most people can get away with eating a light meal up to 1.5 hours before a run but stay away from red meat and hard cheese in the four hours before a workout. It is extremely important to refuel by eating a high carb meal within 1.5 hours after a workout because the body absorbs and replenishes its depleted glycogen stores very efficiently during this window of time.
Supplements: Most people with a normal diet do not need vitamin supplements. However, because you will be pushing the envelope over the next few months, it is worth taking a multi-vitamin to ensure that you are not lacking any essential vitamins and minerals. Distance runners often suffer from low iron, which will give you a feeling of exhaustion. In addition, your immune system is slighly suppressed after an intense workout thereby rendering you more vulnerable to catching a cold. Additional doses of Vitamin C can help address this. Unless, you suffer from a specific and pronounced deficiency of a particular nutrient, I recommend taking one-a-day Centrum Performance to make sure that you ae covered against any deficiencies.
If you are over 40 or have aching joints, you may also want to consider taking glucosamine tablets. Research suggests (albeit inconclusively) that glucosamine may help repair the cartilage that erodes with age and can become painful with excessive pounding on the joints.