This month marked three years since I started writing articles for RunnersConnect.net investigating what the scientific literature has to say about a wide range of running-related topics, from injuries to training to peak performance on race day. At the end of each year, I've made a list of one useful tip or interesting fact that I learned from each week's research. Here are fifty-two more things I learned from reading scientific research this past year, one from each article. If you want to see all of the material I've written, head on over to the blog section of RunnersConnect! Also feel free to check out the yearly lists from 2013 and from 2012.
1. Celiac disease, which affects around one percent of the population, can cause a wide range of vague, non-specific symptoms that can interfere with your training, like joint pain, extreme fatigue, weight loss, gastrointestinal problems, and anemia. Further, even once you've adopted a gluten-free diet, it can take a while for your body to return to normal.
2. If you choose to eat a vegetarian or vegan diet, you're more likely to have iron-deficiency anemia, amenorrhea (if you are a woman), and insufficiently vitamin B12 levels. Though it's very possible to have a complete diet as a vegetarian or vegan, you need to take extra care to ensure you get enough protein, vitamin D, and iron, and you should probably take a vitamin B12 supplement or eat foods that are fortified with it.
3. Scientific findings can run contrary to your own experiences. The research says it's okay to run when you have a cold, that the speed of your daily runs does not affect your injury risk, and that it's okay to do some running on an injured area, as long as you monitor your pain and stop before it's over 5/10 on the pain scale. In my own training, I can't get away with any of this! There might be subtle reasons why the findings from one study don't apply to your own experiences.
4. The faster you run, the greater the proportion of your energy that comes from carbohydrates. This has some major implications when it comes to running out of fuel in the marathon. The people most at-risk for "hitting the wall" before the finish of a marathon are very fit runners who can run at a high percentage of their VO2 max, and heavier, overweight runners—especially if their extra weight is not in their legs.
5. When planning out a fueling strategy for a marathon, you should generally shoot for taking in 60 grams of carbs per hour of running. If you have had major problems with hitting the wall, you may consider increasing your carb intake to 90 grams per hour. However, if you've had gastrointestinal problems from trying to refuel, you might want to cut this down to 45 or 30 grams per hour.
6. Gels, sports drinks, and energy chews are all equally valid choices for refueling during a long race. None of them offer a distinct physiological advantage, so feel free to choose whichever suits you best.
7. Electrolytes aren't all that important for endurance events. There's no good evidence that you need to replace the salt you lose in your sweat—it appears that your body intentionally modulates the amount of salt you lose in your sweat to keep the concentration of electrolytes in your blood constant, so there's no need for salt tablets or super-salty sports drinks.
8. There's no magic formula for carbo-loading. All you need to do is increase your carbohydrate intake by 50-75% over the last few days leading up to a long race (over 90 minutes), and you don't need to do a "depletion period" prior to it to get the benefits of carbo-loading.
9. In a marathon, elite Canadian runners consume between 16 and 26 fluid ounces of liquids per hour of running and about 50-75 grams of carbs per hour. Elites use a combination of gels, solids, and sports drinks according to personal preferences.
10. When runners collapse after finishing a race, it's usually (though not always) from a sudden drop in blood pressure that's triggered when you stop running. After laying down for a few minutes and elevating their legs, they'll be fine. When runners collapse during a race, however, it's much more likely that they're having a medical emergency like hyponatremia or sudden cardiac arrest.
11. Some research suggests that taking vitamin C before and after completing an ultramarathon can decrease your risk of getting sick. Over half of the finishers of a 90km ultramarathon in one study came down with a cold in the weeks following the race!
12. However, try not to load up on antioxidant supplements in general. They can inhibit your body's adaptation to exercise: oxidative stress is a big part of improvement! Fruits and vegetables are probably okay, though.