|Icing eases inflammation and heat speeds healing|
In order to do this rebuilding, your body must have the raw materials, food, and time to put the structures back in order. Your muscles store glycogen, which is an important source of energy for exercise.
After a big run your glycogen stores have been emptied out, which means your fuel gauge is closer to empty. I believe it's imperative to eat a good, balanced post-run or post-race meal. And pretty quickly--you should consume something within an hour of a hard workout. Definitely make sure you make up the calorie deficit within the day.
After running one marathon, I ate a real "meat and potatoes" meal for dinner, and that was probably the best I've ever felt post-race.
Pamper yourself when you've worked out hard. Your body works hard for you, and it deserves treats now and again. If you like ice, hot tubs, hot baths, saunas, or massages, go for it. Anything that increases blood flow to the muscles helps them heal. Ibuprofen can be helpful in getting through the few days post-race.
It's like owning a car. The better you take care of it, the better the performance and longevity.