Sleep scientist and psychologist Merijn van de Laar's How to Sleep Like a Caveman: Ancient Wisdom for a Better Night's Rest provides an entertaining exploration of the contradictory claims of contemporary sleep researchers, commercial interests, and generally accepted wisdom to arrive at a balanced and reasoned conclusion about what constitutes the "right" kind of sleep for different groups of people at different times in their lives.
First, van de Laar teases out the distinctions between concepts such as "sleep pressure," "fatigue," and "sleep inertia" and debunks the "absurd standards of sleep duration" that exacerbate negative perceptions that individuals have about their own sleep. He reassuringly notes that in 2015, "the US National Sleep Foundation downgraded the required sleep duration for adults, concluding that 6 hours of sleep can also be sufficient."
As to the "caveman" referenced in the title, van de Laar explains that prehistoric populations--and indeed contemporary people who live in societies reminiscent of preindustrial cultures--didn't perceive fragmented sleep or longer periods of waiting to fall asleep as negative.
Van de Laar also compellingly discusses disorders such as sleep apnea and presumed connections between shorter sleep cycles and obesity, diabetes, and cancer. He delves into the variables of light, temperature, sleep hygiene, and environment, including sleeping surfaces and companions.
How to Sleep Like a Caveman is a delightful read for anyone interested in the ins and outs of how human beings spend (or try to spend) a third of their lives, and how to improve the experience. --Elizabeth DeNoma, executive editor, DeNoma Literary Services, Seattle, Wash.