All types of singing and Whistling along with air through the windpipes have positive psychological effects on us.  When signing our body releases endorphins, endorphins are produced by the central nervous system and pituitary gland, they are chemicals released by the brain that make our body "feel good".  Singing in front of a crowd at an affair or in a karaoke setting, naturally builds confidence which has its obvious effects of confidence building along with other of general well beings.  But, from all types of singing, choral singing seems to have the most dramatic effect on people's lives  Studies have shown that people who sing in choirs rated their lives as happier than people who sang in other formats.  From personal experience I can say that when I volunteer at a nursing home i see the seniors who take part of the choir they seem to be happier and more lively.  These residents also have proven to show less signs of anxiety and depression levels.