As someone who writes about sleep for a living, I thought I was doing everything right to sleep through the night: consistent sleep schedule, no caffeine after midday, and a calming nighttime routine. So when I started waking up around 2 a.m. night after night, I was baffled.

Why was my sleep suddenly being sabotaged? After combing through my routine for the culprit, I realized that a supposedly 'healthy' bedtime habit could be the cause of my middle-of-the-night insomnia: my sleepy tea.

Key take-aways: At a glance

My bedtime habit: I was drinking sleepy tea every evening. It was causing me to wake up around 2 a.m. and even though I wasn't desperate to use the bathroom, once awake I couldn't go back to sleep until I did use it.

The temperature trap: Drinking hot liquids too close to bed can raise your core temperature.…