I am a terrible sleeper. And it’s a particular type of poor sleep: I have no difficulty falling asleep but I rarely stay asleep through the night. Sometimes, I take melatonin to help, but I try not to as it leaves me feeling groggy the next day. I used to despair about it – does everyone have this issue? – until I listened to an interview with an evolutionary biologist (I stupidly lost the link) who explained why people tend to wake at about 3 a.m. and stay awake. He said that it is our lizard brain – our fight or flight – looking out for us, after all these years… Apparently, we haven’t evolved to the point that our lizard brain fails to understand we no longer need to worry about woolly mammoths waiting outside the cave to avenge their dead relatives, or rival cave guys breaking into our lovely abodes to muck up our cave art. Oddly, this made me feel better. And now, when I wake up at 3 a.m., I keep that in mind and it does help.