The recovery advice given by sports doctors is like an extra dose of punishment. Sit in a cold bath, preferably with added ice. Drink some water, but not too much. Eat some salty food, but only a bit.
What's the point? In the terrible last five miles - that purgatorial final stretch down the Embankment where you were swearing to God on your children's eyes that you would never ever do anything like this again just so long as He could bring it to an end - every fibre of your body shrieks in agony. Nothing's actually going to make you feel better and whatever you do, tomorrow you'll feel even worse. Scientific research on the subject is conclusive: training for the marathon is good for you; running the marathon isn't.
There's nothing much you can do to make yourself feel better, short of a full-body amputation. The only thing that can really harm you is drinking too much water. It can lead to hyponatraemia, a sodium deficiency that can kill you. Best to stick to champagne. And have a hot bath. Your body can't tell the difference. It's just pathetically grateful not to be moving any more.
Actually, it's all right for the participant. You just lie there, on your sofa or in a transparent tent, and people bring you things and offer to give you a massage, which you turn down because it would hurt too much. Now everything hurts too much.
The recovery is worse for everyone else. For the streets of London, clearing up the plastic bottles and sending them in containers to China, hosing down the hedgerows and front gardens of Greenwich and Blackheath. For the lovely people who lined the streets from Charlton to Parliament Square and have overamplified versions of Keep on Running and Born to Run ringing in their ears for days afterwards.
And worst of all, there's your family and friends. They've survived six months of split-times and sweaty running clothes and "I think I've got a twinge in my knee" and comparisons between types of running sock, but what they don't know is that when you made that oath to God on your children's eyes, you had your fingers crossed.
