Four years ago, Dutch duathlete Huub Mass was competing at world level in shorter events, but suffering diarrhoea and vomiting when attempting longer races. He approached sport and exercise nutritionist Asker Jeukendrup.
"He was convinced he was better suited to the longer events, and had tried everything to fix his problem," says Jeukendrup, who is based at University of Birmingham School of Sport and Exercise Sciences.
Luckily, Jeukendrup was able to uncover the culprit: intolerances to fibre and lactose, which meant they weren't sufficiently absorbed. After cutting his intake of dairy products and fibre before events, Mass went on to become a world champion.
When common health issues such as allergies, headaches or acid reflux strike mid-run, as they did to Jeukendrup's patient, it is sometimes hard for you – or your doctor – to figure out and fix the problem. Here, experts offer simple solutions to six symptoms that strike runners.
Symptom: A burning sensation in your chest or throat
The diagnosis: Acid reflux – or heartburn – is the bubbling up of stomach acid into the esophagus. "Vigorous exercise can cause reflux even in people who don't normally have a problem with it," says Jeukendrup. "Running jostles the contents of the stomach, and in certain people the pressure relaxes the valve that normally keeps acid in its place – the oesophageal sphincter – allowing acid to come up."
The fix: Avoid common trigger foods – caffeine, chocolate, mint, onions and citrus fruits – at least two hours before you run. "I have noticed that red fruits and vegetables in particular can be a common cause in some runners," says Jeukendrup. Also, loosen your waistband and fuel belt: if they're too snug, they can squeeze open the valve that keeps stomach acid down.
Symptom: You finish a race and your head is pounding
The diagnosis: An exertion headache, which is essentially a tension headache. "This occurs when the upper back and neck muscles tighten, with this tension transferring to the head and face," says Greg Whyte, from the Research Institute for Sport and Exercise Science at Liverpool John Moores University.
The fix: Warm up your neck and upper back with self-massage, as well as doing neck and shoulder rolls. This will help prevent the fatigue and cramping in those areas that can lead to headaches, says Whyte. Also, keep your shoulders relaxed throughout your run – once per mile, shake out your arms.
Symptom: You feel sluggish and drained during runs
The diagnosis: If sleep deprivation or overtraining isn't to blame, your iron stores may be low. Iron is necessary for the production of hemoglobin, the protein of red blood cells that carries oxygen to your muscles. Low iron means less hemoglobin – and less energy to run.
The fix: If you think you might have an iron deficiency, your first stop should be your GP for a blood test. "What's normal for a non-runner might be too low for runners," says Jeukendrup. "Even a relatively mild deficiency can cause symptoms." The best nutritional sources of iron are beef, fish and poultry, which your body absorbs better than the plant-based iron found in fortified cereals, soya beans and kale, says Jeukendrup. "For optimum absorption, include some vitamin C in your meal," he adds. Your doctor may also recommend an iron supplement.
Symptom: Post-run coughing
The diagnosis: Exercise-induced asthma, a condition brought on by the constriction of the muscles surrounding bronchial tubes. At rest, you breathe more through your nose, which warms and humidifies air. "When you're running and breathing through your mouth, the air that hits your lungs is colder and drier," says Andy Jones, chair of Applied Physiology at University of Exeter's School of Sport and Health Sciences. This causes coughing, wheezing and shortness of breath.
The fix: "Walk for five minutes before picking up your pace to give your lungs time to adjust to the effort of running," says Jones. When your lungs are warmed up gradually, they can handle a heavier breathing rate. "Wearing a face mask or scarf can increase the humidity and warming of the air before you breathe it," adds Jones. A vitamin C supplement may help, too. An Indiana University study found that participants who took 1,500mg of vitamin C for two weeks cut their asthma symptoms in half.
Symptom: Itchy bumps, wheezing, feeling flushed or tingly
The diagnosis: Exercise-induced urticaria (hives) is a mild allergic response (to food, medication, clothing, detergent or pollen) that's set off by physical activity. "It's the combination of the allergen and exercise that causes the reaction – although we're not sure why," says Whyte.
The fix: Seek medical attention if you have these symptoms. Anaphylaxis, a more severe – and frankly, rare – reaction can cause facial swelling and difficulty breathing, says Whyte. To help your doctor pinpoint the cause, keep a log of where you ran, what you were wearing and what you ate beforehand. Once you identify your allergen, limit your exposure to it within two hours of running. Taking an antihistamine like Claritin before running can also help.
Symptom: Abdominal pain, bloatingThe diagnosis: Gas. During an intense bout of exercise, blood moves from the digestive tract to the legs, leaving less blood to help with digestion.
The fix: Fruits, beans and vegetables – great foods for runners – contain fibre and sugars that commonly lead to gas. Dairy and wheat can also cause trouble, especially if you're intolerant or allergic. Eliminate these foods from your diet one at a time for a week to see if your symptoms ease. Then avoid the offenders at least three hours before you run, says Jeukendrup. "This will ensure they are completely absorbed by your intestines." But you don't have to miss out on your energy foods forever. "You can train your gut by starting to eat smaller amounts before a run and building this up over time. You'll find your gut is surprisingly adaptable."