Alarm clocks are a common enemy of dreams, Naiman notes, because waking up to the trill of an alarm clock “shears off” our dreaming periods (“Imagine being abruptly ushered out of a movie theater whenever a film was nearing its conclusion,” he writes). So are alcohol and cannabis, which can disrupt REM sleep significantly, and even sleeping pills, which increase light sleep at the expense of the deeper, more high-quality stuff. Artificial light from digital screens, lightbulbs and city lights cut into REM, too. Finally, sleep disorders such as insomnia and sleep apnea have increased in recent years — likely due to the same factors as sleep deprivation, he notes.

What Naiman doesn’t say, but feels relevant, is that it is especially hard to safeguard our dream sleep because there’s so little social or financial incentive to do so. For most of us, sleeping falls lower on the priority list than both work and play.