INNER CLOCK: Living in Sync with our Circadian Rhythms

Dividing her subject into three sections, "Clocks", "Broken" and "Reset", the author uses her expertise in environment and medicine to unpack the mysteries of our body-clock. Everyone has experienced the effects of jet-lag, but we may be less aware of the body's regulatory mechanisms in our everyday lies. Artificial light or air pollution can sabotage sleep, reduce productivity and open the way for common ailments. Our physiology and behaviour evolved to be rhythmic, in line with the sun, temperature and tides, and today's renaissance in circadian studies is helping to recover lost rhythms, leveraging their power for a healthier and more sustainable world. The author's insomnia before big events prompted her to investigate how living in harmony with circadian rhythms can benefit the individual. She experimented by spending 10 days in a bunker with no visible night or day, guessing the time and reporting back to her researchers. Her closest guess would be 9 minutes off. Body rhythms like temperature and glucose steadily diverged during the period of light deprivation. The author investigates windowless classrooms, energy-efficient windows, blue-filtering glasses, and the pros and cons of LEDs. Sleep strategies for people such as sailors or shift workers with mismatched hours all come under her scrutiny, with younger people tending to find it easier to recalibrate their circadian rhythms. Experiments with different school starting times yielded corroborative results, while the Covid pandemic boosted momentum for circadian medicine as researchers found tests and mRNA jabs were more effective in the middle of the day, though the author also caveats that simply getting the jab is always more important. The conclusion is that the immune system is the most circadian of the body's mechanisms. 351pp.