Trying to find ways to de-stress

Andy and the baby have been going to bed early, so it gives me time to study, or we can try to do something fun. Last night, I told my husband to take our ten-year old daughter Gabby out to a movie. It was a 8:30pm show, and they were home by 10:30pm. I was studying for my final exam kid-free, so it was nice. I also watched an episode of Grey's Anatomy, which was nice. I have a lot of shows to watch that have been recorded. 

I'm also trying to exercise on our stationary bike in the basement if I can, a few times a week. I've been having trouble with heart palpitations that come on with anxiety, and not getting enough sleep or water. I've read that it is common to start having heart arrythmias/ heart rhythm issues after the age of 40. I also know we've had 8 long years of chronic stress with all of our worries about Andy, so I wonder if the two could be related. I never exercise anymore, due to lack of time. I stay in shape due to a fast metabolism/ genetic reasons, but I do need to get my heart rate up more often in a healthy way.