I use to feel the same way, crows. Rule 1 is get a stationary bike. Start at 5 minutes @ target heart rate. Rest 1 day. If 5 minutes was okay go to 6 minutes. Rest 1 day. If 6 minutes was not okay stay at 6 minutes. Rest 1 day. If 6 minutes was okay go to 7 minutes. And so on until you get to 25...