38 percent of Americans describe themselves as “always” feeling rushed. No other warm-blooded creature lives this way: ignoring seasonal patterns, ignoring rest. We alone keep working 24/7, under the false suns of our fluorescent lights. It is as if we hope to rid ourselves of the natural world entirely: discarding not just our own circadian rhythms, but also the larger cycles of the moon and stars, the tides, the solar year. And yet, it is useful, surely, to have some grasp of what the experts call “chronobiology”—to recognize the ways in which our bodies are in fact entrained not to clocks or computers or our weekly schedules, but to the ancient, powerful rhythms of the larger universe. In the course of a day, our hearts will pound out a quiet drum of sixty to eighty beats per minute, speeding up as we race to catch a bus, slowing down when we take a nap. Our body temperatures will rise and fall by a degree or two, reaching peak efficiency late in the afternoon. Our cells will multiply and divide and replace themselves as necessary; hormones and enzymes will be produced. Women in their child-bearing years will move with greater or lesser ease through the different stages of their monthly cycles. Meanwhile, rain or shine, our attention will ebb and flow throughout the day: an hour and a half of concentrated attention, a short break; another hour and a half, another break.
~ Christian McEwen, World Enough & Time: On Creativity and Slowing Down.