3. Sleep from a public and economic perspective
In addition to the more than relevant issues of health and quality of life, how much and how well we sleep seems to also have an impact on the economy and productivity. “The factors that determine or influence productivity are highly complex and difficult to lock down,” recognized David Gozal. “But some studies say it increases up to 16% with just one additional hour of sleep.” Others, on a countrywide scale, put the repercussions of insufficient sleep in the millions of dollars, which would mean 1.56% of the German GDP, 2.28% that of the United States or 2.92% that of Japan.
Although there are individual variations, the maximum average productivity is reached with approximately 9 hours of sleep each night. This figure is at the top of the range established by the National Sleep Foundation, which recommends between 7 and 9 hours. These figures, however, don’t correspond with some controversial studies that have attempted to determine how many hours we should sleep ‘according to evolution’.
Jerry Siegel, professor at the University of California, has spent years studying three groups of people who live like traditional human societies did: in a natural environment, without electricity. They are the Hadza in Tanzania, the San in South Africa and the Tsimane in Bolivia. According to Siegel, “They all sleep between 6 and 7 hours a night on average (one more in winter) and just 15% of them take a nap. They don’t go to bed when it gets dark; they wait at least three hours. And they wake up very regularly just before dawn, leading us to believe it isn’t light that regulates their sleep, but temperature.” Gozal, however, believes this data must be taken with a grain of salt. “We don’t know, for example, whether they take micronaps throughout the day that are not being recorded. And we don’t know if the conditions they live in are ideal either.”
In any case, living conditions today are an obstacle to quality sleep. One of the major issues is shift work, which affects between 18% and 25% of the Western population. “It is a serious problem,” explained Manolis Kogevinas, professor at the Barcelona Institute for Global Health. “The resulting changes to the circadian rhythms are associated with increased risk of obesity, cardiovascular disease and stroke, and probably with some types of cancer, especially those that are hormonal, like breast cancer.”
To fight the epidemic of insufficient sleep, we have to act on many fronts and on a large scale. One of these fronts is the timetable reform that has been hotly debated for years. In 2013, a committee of experts was set up in Catalonia, which has gotten a commitment from the Parliament to implement this reform by 2025. The goals of this reform include adjusting official time to solar time (including staying on winter time), moving forward the times when we work, eat and sleep, and raising awareness of their importance. Ferran Barbé summed it up: “lunch at 1 pm, no leaving work after 6 pm, dinner at 8 and in bed by 10.” For Salvador Cardús, professor at the Autonomous University of Barcelona and member of the committee of experts for timetable reform, it is an issue that entails equality and wellbeing, but there is a lot of resistance that must be overcome: “Much of it comes from the power structure, but also some individual reticence from those who consider timetables set in stone, who say: it’s always been this way, it’s due to the climate, our national character….”