In order to stay in a good healthy shape I am sure it is necessary to keep the exercise levels high in order to maintain a healthy cardio system. The problem with this is the fact that it uses up quite a lot of calories and can result in you feeling quite tired. I have managed to get around this problem by supplementing with a sports supplement called Sci-MX Lean Grow MRF. I use it twice daily and it helps me recover from my runs by supplying my muscles with much needed carbohydrates and protein. I find it useful to order this product over the internet as I think you can get the best price.