On “Circadian Rhythms: A Very Short Introduction”

Notes These are some things I learned from the book Circadian Rhythms: A Very Short Introduction by Russell Foster and Leon Kreitzman: While mammals only have photoreceptor (light-detecting) cells in their eyes, other vertebrates also have photoreceptors elsewhere, such as in the pineal gland – sufficient light can penetrate through the tissues to reach it. Many invertebrates are translucent and have photoreceptors in many parts of their bodies. Technically, bears don’t hibernate. Instead, they just experience ‘winter lethargy’. There are other animals that go into true hibernation, with much greater decreases in heart rate. A chart in chapter 2 shows average changes across the day for adult humans. For example, 10-12 in the morning is (on average) the best time for logical reasoning, and 3:30 in the afternoon is when reaction times are fastest. Reflections The detail in the chart in chapter 2 leads me to wonder just how much benefit we could gain from strictly aligning activity to…