If you go into each week doing the same workout routine, let me be the first to tell you to 'Stop'! You have to mix up your exercise pattern. It is crucial that you trick your muscles each time to produce long term results and avoid plateauing. Our bodies are built to adapt to difficult physical challenges. What was tough to do, like running a mile, one day will not feel as hard a month later if you continue to do it everyday. What the effects of running the initial mile had on you physically won't be the same a month later. The body will adapt to the run and no longer see it as a challenge, causing your metabolism to slow down.