Why am I always tired on the sofa, but wide awake once I go to bed? Deborah Wright, Minehead
Post your answers (and new questions) below or send them to nq@theguardian.com. A selection will be published on Sunday.
Why am I always tired on the sofa, but wide awake once I go to bed?
The long-running series in which readers answer other readers’ questions on subjects ranging from trivial flights of fancy to profound scientific and philosophical concepts