I recommend listening to this really fascinating radio programme about the brain and relaxation. We are all leading increasingly stressful lives - perhaps money problems, exams and deadlines or simply too much viewing other people's wonderful lives on facebook.
The programme shows that trying to make decisions under stress can lead to mistakes or poor judgement. They recommend mindfulness as a way of lessening anxiety and creating a relaxed brain.
Essentially mindfulness is yoga without the body bit. That's why I reckon yoga is the better option. Me, biased! And if you don't fancy either, then the best way to go is laughter. Make sure your viewing/listening diet is full of belly-laughter provoking stuff. Not those miserable dramas like Liar!
Do try and listen to the Radio 4 programme (How to have a better brain - Relaxation).