Yoga, and specifically Kundalini yoga, is an ancient technique for calming the nervous system which is one of the keys to anxiety relief.
Breathing through the left nostril for five minutes can calm you and lower your blood pressure.
Try it Now: Sit with your back straight. Close your right nostril with your right thumb – your other fingers are stretched straight up as antennas. Close your eyes and concentrate on your Third Eye (center of forehead). Begin to breathe long and deep only through your left nostril.
(Adapted from kundaliniwomen.org)