Hi for the first week i felt perfectly fine so i did a lot of intense exercise on the monday after my first weigh in. Determined to loose more, I over did it. I collapsed. I'm banned from exercise for four weeks to let my body adjust and i screwed up my weight loss on that second week. My advice is don't do any for the first two weeks then slowly start it, maybe a couple of 15-30 minute walks. Add in a few extras when you don't feel tired or anything from those walks until your at a reasonable level of exercise.