María Ángeles Bonmatí, physiologist: ‘Some people say that the more you sleep, the less you live. They are totally wrong’

Mythology, religion and art are full of references to the difficulty of falling asleep. Writers like Jorge Luis Borges, Julio Cortázar, Juan Rulfo and Sylvia Plath suffered from insomnia and addressed it in their works. In his letters, Franz Kafka mentioned his problems sleeping, which even prompted a scientific study published in The Lancet to analyze how insomnia might have influenced the Czech author’s work.

“There have been very prolific and successful authors who have suffered from insomnia. For example, one tends to think that Kafka’s work is very much conditioned by that insomnia. But we can also ask ourselves what geniuses like Kafka would have done if they’d had a good rest, what level their work would have reached without such problems,” said María Ángeles Bonmatí, a University of Murcia PhD in Physiology and a researcher in chronobiology. In her book Que nada te quite el sueño [Let Nothing Keep You Awake], Bonmatí staunchly argues that good sleep is a fundamental pillar of health. “The cases in which poor sleep has an artistic or financial benefit are rare,” she said. Normally the opposite is true, she added: insufficient sleep creates a number of problems.

Question. In Funes the Memorious, Borges wrote that “to sleep is to be distracted from the world.”

Answer. In certain contexts, there seems to be the idea that time spent sleeping is wasted time, unproductive time, because when we’re sleeping we don’t produce or consume, which seems to go against what the world in which we live demands.

Q. Sometimes it even seems like not getting much sleep is a status symbol these days.

A. I remember that when I was a teenager I had a teacher who bragged to us, his students, that he slept very little, no more than five hours a day. He told us that the more he slept, the less he lived. That view is totally wrong. It is true that there are people who need less sleep, and they are probably fine with five hours of sleep, but that doesn’t mean that [everyone] has to make that a goal. On the contrary, for most people, too little sleep is going to mean being far less productive in their daily lives, and [it’s going to] diminish their physical and cognitive capacities.

Q. Speaking of productivity, you explain in the book that having a population that’s dead tired is not a very profitable situation.

A. Citizens’ poor sleep costs between $50 and $60 billion a year in countries such as the United Kingdom and Germany; that is more than 1.5% of those countries’ GDP. As we said, sleep deprivation’s impact on productivity is clear, but we also know perfectly well that poor quality sleep is associated with the onset of many diseases, which implies significant economic costs. So, this argument highlighting the economic importance of sleep is welcome because many people do not see beyond economic data.

Q. “Sleep Is Life,” is the title of the second chapter in your book.

A. Life cannot be understood without sleep. That is why I also included a chapter about sleep in other animals, to convey the idea that sleep, despite a number of disadvantages — it disconnects us from the environment and reduces our ability to react — is an essential physiological process. Otherwise, we would not have maintained it throughout our evolution as a species.

Q. This year’s World Sleep Day has the slogan “sleep is essential for health.” How does insufficient sleep damage our health?

A. Given that sleep is essential for our whole organism to function properly, not enough of it will affect all our physiological processes. Therefore, insufficient sleep has been linked to the onset of metabolic diseases and cardiovascular diseases, a greater propensity to develop infectious diseases and a higher likelihood of getting certain types of cancer and developing neurodegenerative diseases, like Alzheimer’s disease. We must also add the issue of mental health, with which sleep has a bidirectional relationship: with poor sleep, sooner or later mental health problems will develop, but often sleep problems are also a symptom that something is wrong with our mental health. In fact, in many cases difficulty sleeping is one of the first symptoms of depression.

Q. Is poor sleep a public health problem? For instance, in Spain it’s estimated that over 30% of citizens wake up every day not feeling like they’ve had a good night’s sleep or they end the day very tired.

A. Given all the implications of not sleeping well, I think it is an issue that should be given much more attention than it currently receives. Among many other things, the authorities should protect the environment in which we rest. To sleep, we need darkness and silence. In cities, the issue of silence usually leaves a lot to be desired. There are many people who cannot sleep well in their homes because of the sounds of nightlife, or because of the noise of street-cleaning machinery, which often doesn’t even respect [the time we’re typically sleeping].

Q. In your book, you explain that we now know that to improve our quality of sleep, it is important to have a good contrast between day and night, good lighting during the day (preferably natural light) and darkness at night.

A. We know this, but we nevertheless have a pattern that, if it’s not inverted, lacks significant contrast. We spend our days indoors, often with very poor lighting; I have even seen windowless offices. And then we leave work, and we get hooked on the light from screens, or we go into a hyper-lit shopping mall at 9 p.m. In addition, we have a very late dinner, which also means that we go to sleep with a digestive process in progress, which is not conducive to sleep. Our lifestyle certainly does not favor a good night’s sleep.

Q. We are increasingly stressed out, glued to screens, and living in cities that are becoming brighter, noisier, and warmer because of climate change. That’s not a scenario that is very conducive to sleep.

A. Not really. It has already been shown that people’s time asleep is being lost as the minimum temperatures at night increase. However, I believe that if we become individually and collectively aware of this issue, we can begin to protect our sleep environment.

Q. What do you think about daylight saving time?

A. (laughs) This is a very controversial issue, but as a researcher in chronobiology I have to say that the current scientific consensus advocates abolishing the time change and maintaining a standard time; that is best physiologically. From a scientific and health perspective, the conclusion is clear, but there are other social and economic interests that go against that.

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