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Can exercise help to counteract the effects of poor sleep?

A few years ago, I was in Spain in the province of Toledo. I visited the Museo-Casa de Dulcinea, the house of Doña Ana Martínez Zarco de Morales, who is supposed to be the person who was fictionalised by Miguel Cervantes as Don Quixote’s love interest. The Spanish are indeed very proud of Cervantes. I was told several times during my travels through Spain that after The Bible, Don Quixote is the most translated book ever

In Don Quixote, Cervantes extolls the virtues of sleep thus: 

“Now blessings on him that first invented this same sleep! It covers a man all over, thoughts and all, like a cloak; ’tis meat for the hungry, drink for the thirsty, heat for the cold, and cold for the hot. ’Tis the current coin that purchases all the pleasures of the world cheap; and the balance that sets the king and the shepherd, the fool, and the wise man even.” 

I am a notoriously poor sleeper, and always have been. I often wake up at night to jot down ideas, and many of my novels were written at night. But over the past ten years, there have been increasing voices warning people like me of poor health and impending doom. The benefits of sleep were being mentioned everywhere. Sleep seemed like an internal charger for our bodies, conveniently wired into the roof of our bodies. 7-9 hours was all it took to power our days. For a skin doctor like me, dermatology journals wrote that chronic poor sleep quality is associated with increased signs of intrinsic aging.

Matt Walker wrote the book Why We Sleep: Unlocking the Power of Sleep and Dreams (Scribner, 2017) that was released in the same year as my book, The Genetics of Health (Simon and Schuster). Two years later, Matt was invited to deliver a TED talk on sleep that has over 18 million views! In this talk titled Sleep is your Superpower, Walker says: “We discovered that you also need sleep before learning to actually prepare your brain, almost like a dry sponge ready to initially soak up new information. And without sleep, the memory circuits of the brain essentially become waterlogged, as it were, and you can’t absorb new memories…what you find is a quite significant, a 40-percent deficit in the ability of the brain to make new memories without sleep.” (He also said that men without proper sleep end up with progressively smaller cojones, but let’s not go there). 

I wasn’t doubting Matt’s research methods, but I’ve never had problems with absorbing new information or remembering things. My memory seems fine (for now, anyway). I have always said I seem to be an eternal student with accumulated degrees in medicine, law, philosophy, and ethics—which makes me full of useless information! Was I an outlier or was there something I was doing that was counteracting my lack of hours of sleep?

The National Heart Lung and Blood Institute (NHLBI) differentiates sleep deprivation and sleep deficiency—the former is when you don’t get enough sleep (like someone with a new baby, for example); the latter includes the former group plus people that don’t sleep well enough to get the sleep their body needs along with those with sleeping disorders such as sleep apnoea. The NHLBI also says that sleep deficiency is linked to many chronic health problems, including heart disease, kidney disease, high blood pressure, diabetes, stroke, obesity, and depression.

Sleep is essentially a period of rest that is followed by wakefulness. Our body has internal clocks that work on a 24-hour cycle and are regulated by sunshine hours, light, darkness, and our sleep schedules. This internal clock system is regulated by melatonin, the sleep hormone, which is a central part of the body’s sleep-wake cycle.

When we go to sleep, we initially have REM (rapid-eye-movement) sleep, which is followed by NREM sleep (non-rapid-eye movement). During REM sleep, your brain is still active, and you are not in deep sleep which is why this is the stage when you have more vivid, colourful, or bizarre dreams. Our bodies cycle through REM and NREM stages approximately 4 to 6 times each night, averaging 90 minutes for each cycle. Your ability to remember a dream depends on the stage at which your alarm goes off in the morning or you are woken up; if you get up in the middle of REM sleep you are more likely to remember a dream. However, it must be said that not all dreams are during the REM phase. 

NREM sleep is further divided into three stages, N1-N3. Men tend to spend more time in N1 and therefore get up more times at night and are therefore more likely to whinge about being sleepy during the day. Women, in contrast, maintain slow-wave sleep longer than men, and therefore complain about the difficulty falling asleep rather than daytime sleepiness (except when pregnant). Studies have shown that pensioners—adults older than 65—generally wake up approximately 1.5 hours earlier and sleep one hour earlier than adults half their age. 

I have always regarded the brain as an organic supercomputer. Increasingly, researchers seem to be saying that sleep allowed the computer to reboot itself for optimal performance. For example, Johns Hopkins sleep researcher Patrick Finan says that not getting enough sleep can affect your mood, memory, and health in far-reaching ways. Finan created a chart for John Hopkins Medicine: The Effects of Sleep Deprivation that I have reproduced below. 

Sleep research has grown the business of sleep to levels one could not even dream off (pun intended). Statista Research Department on July 27, 2022, reported that in 2019, the global sleep economy was valued at about 432 billion U.S. dollars. This industry was forecast to be worth 585 billion U.S. dollars by 2024! The sleep economy includes products, services, aids, and applications connected to sleeping. Almost subliminally—if I was being naïve—my phone keeps offering me Apps and programmes to help me sleep better. No fewer than 12 sleep Apps begged to be downloaded. One promised me that in just 3 days, 97% of people like me reported improvements in wellbeing and sleep. Advertisements, languorous in rhythm and almost dreamy in imagery beckoned me to part with some money as an investment towards good health and youthfulness. Part of what made me resist was the two things that I value most—personal independence and liberty, perhaps a spiritual throwback to my boarding school days.

Essentially, most of the published medical research was saying that my lack of normal sleep should have made me fat, depressed, crave salty food, more likely to catch a cold, develop diabetes and look older than my age. Fortunately, none of that—touch wood—has happened. In fact, until a mild bout of Covid enforced a week off work a year ago, I had never lost a working day due to illness in my 35 years as a doctor! My patients generally think I look younger than my age.

Now evidence is growing that regular exercise may negate the negative effects of poor sleep. A recent study from the European Journal of Preventive Cardiology concludes that the majority of the detrimental associations of the lack of sleep may be mitigated by engaging in a higher volume of physical activity and exercise.  This study tracked the activity of 92,000 participants in the UK –average age 62 and 56% female—using electronic activity-tracking devices for a week to measure how much they moved and slept. These people were followed up over the following decade. In the ensuing seven years, 3080 participants died, mostly from cardiovascular disease or cancer. Those who exercised the least and slept less than 6 hours were 2.5 times more likely to die. It turns out that participants who undertook 2.5 hours of moderate to vigorous exercise a week essentially had no increased risk at all i.e., all the harmful effects of the lack of sleep were eliminated. Maybe that’s the secret as I have just returned from my 8-mile run and am actually writing this blog while I cool off. 

THE END