I don't believe I've ever seen this topic on the electric bass forum so I thought I'd bring it up. Having studied the exercise-and-body-awareness fitness approach named Pilates, I've become aware that I tend to hold my breath when doing any action that is difficult (e.g., lifting a heavy object). Holding my breath happens naturally and unconsciously. but it's counterproductive to relaxed, efficient movement because it promotes muscular tension (whereas exhaling encourages relaxation). I believe this is a viable area of study for musicians. If a difficult passage on the bass, for instance, causes you to catch and hold your breath, you're probably creating unnecessary tension and limiting your ability (as I believe that I sometimes am). When playing, I'm trying to heighten my awareness of my breathing so that I'm as aware of my inhalations/exhalations as I am the tension in my hands, forearms, etc... Any other bassists focusing on breathing?