The long run: how to prepare for a marathon
You can’t choose your parents, so the genetic path to athletic prowess might be blocked, but you can at least eat correctly in order to optimise your performance
The start of last year’s Dublin Marathon. Photograph: Cyril Byrne
‘I’m going to be controversial here, Dublin City University’s sports scientist Niall Moyna warns. “Is it good for people who can’t run a marathon in under 3½ hours to be doing it in the first place?”
“The best can cover 42km in under 2½ hours, but five hours is a lot of running for someone without proper conditioning. There is now evidence that it may negatively impact on their heart function,” he says. “Then you must think about the joints and tendons, particularly as the average person running a marathon may be slightly overweight.”
Moyna, a sports lover and exercise physiologist at the university, has run marathons. He says people should set themselves realistic challenges, such as five five-kilometre races in a year, or a half marathon, rather than doing a full marathon and then hanging up their shoes. “It’s an awful pity when the guy ran from Marathon to Athens it wasn’t five kilometres. It would have served society better,” he says.
Those who want to cover the full 42km in one race, however, will find there are plenty of insights from sports scientists. Most important is to have trained for 15-20 weeks beforehand and to be well fuelled on the day of the race. Everyone has two fuel tanks in their body, Moyna says: their fat reserves and their carbohydrate reserves.
An average person holds about 100,000 calories of fat and 3,000 calories of carbohydrate. The higher the intensity at which you run, the greater your reliance on carbohydrate. If you are untrained, you will burn through this tank quickly. If you run out of carbs, then you hit the wall, because your body can’t get energy quickly enough when you use only fat.
That can be avoided by proper carb intake. With training, athletes can also teach their muscles to use more fat, thus reducing reliance on carbs and allowing them to run for longer at higher speeds.
James Morton, exercise researcher at Liverpool John Moores University, has tested muscle biopsies from runners who take carbs before and during exercise – in line with standard advice – and those who fast before and during training. “When you feed carbohydrates all the time, you block the adaptation of making more mitochondria [the cells’ energy factories] in the muscles,” he has found.
General advice on carbohydrate intake for endurance has shifted, says Ruth Kilcawley, an elite performance nutritionist with Athletics Ireland. The emphasis on loading up on carbs days before an event has fallen off, but do fuel up on the day.
“Take additional carbohydrates in the form of gels or fluids early in the race. Certainly by the 10km mark you should be replacing the fuel you’ve used,” she says. “I like rice-style cake and banana bread.”
But don’t overdo the water on the day. The most important thing is to be hydrated the day before. Drink when you are thirsty.
Kilcawley also stresses correct protein intake: too often, amateur runners focus on chicken, when they need oily fish two or three time a week to support good immune health, and red meat such as beef and lamb, which helps with iron levels.