Early in my running career I discovered the power of a reward after exercise. During the most difficult workouts, I would promise myself a big bowl of ice cream. As I increased my daily running to 20 miles a day--in preparation for the Olympic trials--there were many days when I had to drag myself through some really hot runs. It was wonderful to dive into a half gallon of decadent chocolate chip mint "medicine". But even though I was not gaining weight, I knew that this was not good for my arteries.
I never got tired of this reward and believed that I would not have finished many of the tougher workouts without my "carrot on a stick". But as my mileage decreased, and my nutritional awareness increased, I shifted to other reinforcements.
Simple carbohydrate snacks (mostly sugar, about 300 calories) did not contain significant quantities of saturated fat, and would reload the muscle glycogen better than ice cream when eaten within 30 minutes of finishing a hard workout. I found that this made it easier to run during the first 15 minutes of the next workout.
The ideal reward is often not a food. You need a satisfying experience afterward--one that can motivate you to start and finish challenging workouts. It's even better if the reward actually helps you recover faster. Here are some of my favorites:
I've staged some of my runs near a scenic hiking or bike trail. After the run, I'm rewarded by walking through beautiful scenery, while the walking pumps the waste products out of the tired muscles.
A massage can also reward you with blood flow, as it relaxes the body and invigorates the muscles. On numerous runs, during the last year, the only thing that pushed my motivation button, was the thought of my Human Touch massage chair waiting for me. On one workout, this kept me going for 10 more miles!
What works on one workout may not work another time. So it helps to have several different rewards: a healthy food item, a cool down or tub experience, muscle regeneration, and a delayed gratification special reward at the end of the week or month. Many runners use my running retreats or running schools as a reward. These are fun experiences, with learning.
As you reward yourself, you gain control over your motivation, and that's a good thing.