Yoga used to be an obscure activity, done only by those into new age experiences. But yoga has become so mainstream that it's almost impossible now to find someone who hasn't tried it. There are many types of yoga exercises, which focus on stretching and elongating muscles. There is yoga that focuses on relaxing, but also fitness yoga that gets your heart pumping.
When working out in the sun or heat, be sure to stay well hydrated. Dehydration can occur during any workout or during long stints in the sun or heat, so exercising in the sun greatly increases the risk. Drink several glasses of water in the hours before your workout and enough during your work out to stay hydrated.