The Demands of the Half and Full Marathon

by Karl Gruber
If you’re a runner who has already run a half or full marathon, then you probably have a pretty good understanding of just how different a shorter distance is from running 13.1 or 26.2 miles. New distance runners quickly find that the physical demands of a 5K are vastly different than what your body goes through during a half or full marathon. 
One of the most respected authorities in the field of running is Dr. Jack Daniels, and he states in his book Daniels’ Running Formula that, “What separates longer distance races from shorter distances is that the bulk of a longer race is performed below the individual’s lactate threshold.” See my previous blog Tapping Into Your Running Potential for more.
Daniels goes on to point out regarding running and racing long distances…
- The runner is not going to accumulate very much blood lactic acid (which usually occurs on much shorter distance races at maximum effort)
- The runner will not normally suffer from local muscular stress (as they would during say a 5K race)
- Ventilation is relatively comfortable throughout the race
- The runner’s heart rate will not be at max value, as it will be in shorter races
One of the most important things that you have to learn as you ramp up to the half and full marathon is learning how to properly hydrate and supply your body with enough calories and proper nutrition. This is a lesson learned the hard way by many, many runners, including myself. As Dr. Daniels expertly notes, “Training for longer races must emphasize making the best of available fuel sources, development of a strong aerobic profile, the ability to replace diminishing body fluids, and the ability to maintain an optimal body temperature.”
Early in your distance running career, it is very difficult to gauge how much liquid you lose and the amount of calories (fuel) you burn during a long run. As a coach and distance runner, I would say that the vast majority of distance runners I observe are under-hydrated. 
From the Journal of the American College of Nutrition, Vol. 26, Bob Murray, PhD states in his article Hydration and Physical Performance, “There is little doubt that performance during prolonged, continuous exercise in the heat is impaired by levels of dehydration ≥ −2% body mass, and there is some evidence that lower levels of dehydration can also impair performance even during relatively short-duration, intermittent exercise. Although additional research is needed to more fully understand low-level dehydration's effects on physical performance, one can generalize that when performance is at stake, it is better to be well-hydrated than dehydrated.” 
The bottom line when it comes to hydration and running is that your performance will most definitely suffer without drinking enough liquid. Quoting from an article I wrote for Women’s Running in 2015, “So why is staying hydrated so important during your run? Because water is key in keeping your blood, which contains much needed oxygen and sodium, flowing quickly and easily to your heart, lungs and muscles—as well as helping every body part function at its peak. However, when you become dehydrated, your blood becomes thicker, which makes your heart work harder to pump blood to the body parts that need its fuel. Drinking liquid with regularity during running will then offset your liquid loss through sweating and keep everything balanced and working order.”
As for learning how to consume enough calories to sustain you through 13.1 or 26.2 miles, this is another lesson that is usually learned through trial and error. Consider that your body generally burns approximately 100 calories per mile – which can fluctuate according to your gender, size and effort. Run 26.2 miles, and you burn anywhere from 2600 to 3000 plus calories! So you can see, the gargantuan effort of running a marathon requires a lot of energy. 
First, you must learn how to eat enough calories of complex carbohydrates (the fuel your muscles burn during activity) prior to your long run, while also learning how to consume even more calories while running. Consider that a typical sports energy packet usually contains 100 – 150 calories, and that is enough energy to get you through only one mile of running! When I run a marathon, I carry four to five energy gels and consume one at least every 10 kilometers to “top-off my fuel tank.” 
The real fuel for your body should come prior to your long run. And finding the right nutrition that agrees with your stomach is also very important. As Registered Dietitian Monique Ryan says in her book Sports Nutrition for Endurance Athletes, “Eating too much and eating too close to training or competition are probably the biggest nutritional mistake that a runner can make. Because running jostles your stomach and gastrointestinal system, G.I. disturbance is a more common problem than in other endurance sports.” 
When learning what works for your body with nutrition and hydration, experiment during training, not on race day! I can guarantee that the majority of runners you see making unplanned pit stops or upchucking on the sidelinesare learning what the demands of the half or full marathon are the hard way.

Comments (0)