Chasing the Sun

Profile 256pp £14.99 The Week Bookshop £11.99 This “sparkling study” is also “one of those rare books that could genuinely improve your life”, said James Mcconnachie in The Sunday Times. In it, science journalist Linda Geddes examines the “new science” of sunlight, which increasingly shows that how much of it we get profoundly influences our physical and mental health. That a lack of vitamin D (which our bodies produce when exposed to sunlight) can lead to rickets is well known. But lack of sunlight, Geddes shows, is associated with a “host” of other health risks, including myopia and multiple sclerosis. (The best evidence for the latter, intriguingly, comes from Iran where, following the revolution of 1978-79, “half the population was suddenly denied exposure to the Sun” and rates of MS “increased eightfold”.) Yet despite all the evidence that sunlight is good for us, most of us live “way behind the science”, spending our days in poorly illuminated offices and our nights amid a host of light-emitting gadgets.

Sunlight also plays a crucial role in sleep, said James Marriott in The Times. It “guides” our body clocks, or circadian rhythms, providing us with clues about when to get up and when to rest. This is “illustrated” by the fact that sleep disorders have a high prevalence among blind people. Chasing the Sun is most engaging, said Caspar Henderson in The Guardian, “when Geddes writes about her own experience”. She describes experimenting on herself and her “long-suffering family” by trying to imitate the habits of the Amish, who “shun electric light” and spend much of their time outdoors. Soon, she finds, there are “marked results”: she sleeps better, and becomes more attuned to the wonders of nature, describing the “hoar frost on rose hips” or a winter solstice in Ireland. Such passages inject a “sense of wonder” into an otherwise “fact-filled book”.