One physical activity that will help you coast more easily throughout this special time is swimming. As your back begins to ache, water weight takes over your once shapely legs and the pressure of baby on your bladder prods you to do little more than become a blob on the couch, a swimming pool is a welcome oasis. Many gyms have pools, and several even offer prenatal water classes. If not, don't fret, you can easily create a program on your own.
For just that short time in the water you are basically weightless. 50% - 80% of bone and joint stress is absorbed when exercising in waist to chest deep water. It is a safer and more comfortable environment, even on your back since your fetus will not be depressed as much on the vena cava as on land. You can float and twist without difficulty and you feel like you are flying. The best part is that you can get a valuable cardio workout without even really feeling it.
Water stretching, yoga and aerobics were my favorite activities in late pregnancy. There were days where I just didn't feel like exercising, but once my body hit the water, I felt a rush of energy and peace.