Exhausted all day, then wide awake at 2 a.m. Or asleep easily enough, then jolted at 4 with no way back. Insomnia is one of the most disruptive features of grief and one of the least discussed, and understanding why it happens makes it far less frightening.

Walking to the mailbox feels like a marathon. Choosing what to have for dinner leaves you needing a nap. This is not laziness or a shortage of resilience. It is a physiological reality and there are specific reasons your body is this depleted.