Emily, my periods have been so much easier since exercising too. I retain less water, am less sleepy and moody and they are a lot less heavy than they used to be. My family is particularly thankful for the less moody part.
Christa--I don't know what Dan's particular issues are with anxiety but I have panic attacks. A psychologist (psychiatrist? I dunno. He specialized with people with anxiety issues as a result of drugs) at my church told me that exercise is the best thing for anxiety. With my panic attacks, last September he told me to try exercising as many days as possible (at least 4-5 days a week). He said to do real heart-pumping cardio for 20-30 minutes and see how that helped. At that point I was having 3-5 panic attacks a week. Within a week, they dropped to 1. After a month, I was having 1-2 a month and in the last 5 months the only panic attack I had was right before Jesse's qualifying exams because of all the extra added stress! Anyhow, you might try encouraging Dan to exercise. You could even try doing it together for added encouragement. Jesse used to run with me in the beginning to help me get going.