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Marathon guide: what it takes to run 26.2 miles

A marathon is 26.2 miles, or 42.2 kilometres. Finishing one is within reach of most healthy adults, but it asks for several months of steady preparation and a sensible plan on the day.

Are you ready to train for one?

The marathon rewards patience. It is best attempted once you have been running regularly for at least six months and have completed a half marathon, or can comfortably run 8 to 10 miles. Starting from that base, the training is demanding but manageable. Starting from much less, the jump in weekly mileage is where most problems begin.

Be realistic about time. At the peak of training you will run four or five times a week, with a long run that takes two and a half to three and a half hours, plus recovery afterwards. See a GP before starting if you have a health condition.

Choosing a marathon

Entry routes differ from race to race. The largest city marathons are often oversubscribed and allocate places by ballot, through charities, or to runners with a qualifying time. Many smaller marathons simply stay open until they are full. When you browse events, weigh up:

  • Course. Flat road courses are the most forgiving for a first attempt. Trail and hilly marathons can take an hour longer for the same effort.
  • Support. Crowds help in the final miles. Quiet rural courses need more self-reliance.
  • Season. A spring race means long runs in the dark and cold. An autumn race means long runs in summer, often early in the morning to avoid the heat.
  • Time limit. Check the cut-off if you expect to take more than six hours.

The shape of marathon training

Most plans last 16 to 20 weeks and follow the same pattern: a gradual build, a peak, and a taper.

  • The long run. This is the most important session of the week. It grows by a mile or two at a time, with an easier week every third or fourth week, to a longest run of 18 to 22 miles (29 to 35 kilometres) about three weeks before the race. Run it slowly, well below your intended race pace.
  • Easy runs. Most of your weekly mileage should be at a pace where you can hold a conversation.
  • One quality session. A tempo run, or a stretch of miles at marathon pace, teaches you the effort you need on the day.
  • Rest. At least one full rest day a week. Fitness is built during recovery.

The marathon training plan lays this out week by week. In the last two to three weeks you reduce the distance and let your legs freshen up. The tapering guide explains how much to cut back and why it is normal to feel restless.

Fuelling

Your body stores enough carbohydrate for roughly 90 minutes to two hours of hard running. A marathon takes longer than that, so you need to eat during the race. The point where stores run low and the legs suddenly feel heavy is what runners call hitting the wall.

  • Start taking energy gels, chews or other carbohydrate within the first 30 to 45 minutes, and continue at regular intervals. Do not wait until you feel tired.
  • Rehearse this on every long run, using what you intend to use in the race.
  • Eat more carbohydrate than usual in the two days before the race, and have a familiar breakfast about three hours before the start.
  • Drink to thirst at the water stations. Drinking far more than you need is not helpful.

Pacing

The marathon punishes a fast start more than any other distance. A pace that feels easy at mile 5 can feel impossible at mile 22. Aim to run the first half slightly slower than the second, or at worst the same.

To set a target, put a recent half marathon or 10K result into the race time predictor, and treat the answer as the best case. It assumes you have done the long runs. Then use the pace calculator for your pace per mile and carry a pace band, since GPS watches often read a little long on crowded city courses.

A useful way to think about the distance is that the first 20 miles are transport and the race is the last 6.2. Arrive at mile 20 feeling in control.

Race week and race day

Do very little running in the final week. Sleep well, sort your travel and lay out your kit early. Wear nothing new: shoes should have a few long runs in them, and every item of clothing should be tested for rubbing over at least 15 miles. The race day checklist covers the rest.

Recovery

Expect sore legs for several days, and stairs to be awkward. Walk a little each day, eat well and take at least a week off running, then return gently. Most runners need three to four weeks before they feel normal again.