Singers often say how tired they feel after a rehearsal or workshop. Paradoxically, singers who arrive tired at the start often leave feeling energised. What’s going on? Singing together takes a lot of concentration. You have to listen carefully as you’re learning a new song; pay attention to the choir leader; fit in with other singers in your part; remember how your harmony goes; balance your voice with others; and focus on the lyrics. That level of concentration is a big deal. You’re also breathing a lot more deeply than you do in everyday life. All these things taken together...