Hi there, I have done the Master-Cleanse 3 times now. I workout the wholeeeeeee way through. I cycle, lift, etc. Actually, you will feel REALLY good working out while on the MC. I always listen to my body to tell me how hard I can go though. Just take it day by day! You can drink as much water as you like. I normally just have 6-8 glasses of lemonade and drink 1 gallon of water which is something that I do even when not on the MC. Good luck!