I'd like to add that conscious breathing, mindful breathing, and meditation are some of the best techniques for improving your mood and relieving depression. At the risk of sounding sensationalist, breathing correctly can change your life. It can boost your immune system, change your hormonal balance, and relieve stress.
As we've become a more modern species we've lost touch with the simple things in life. Our bodies are amazing machines and our breath has the power to heal. But we ignore it for iPhones, TV, and distractions. Take the time to breathe and live better!