Berkeley scientists discover the secret to waking up and refreshing

Waking up from a good sleep

Researchers at the University of California, Berkeley found that by focusing on three key elements—sleep, exercise, and breakfast—a person can wake up each morning feeling refreshed and alert.

Tips the researchers outlined: sleep longer and later, engage in physical activity the day before, and eat a breakfast that is low in sugar and high in carbohydrates.

Do you feel drowsy until you have your morning coffee? Do you suffer from sleepiness during the working day?

If you struggle with wakefulness in the morning, you’re not alone. However, a new study from University of California, BerkeleyWaking up feeling refreshed isn’t just a matter of luck, he explains. Scientists have found that paying attention to three factors — sleep, exercise, and breakfast — can help you start your day without feeling dizzy.

The results came from a detailed analysis of the behavior of 833 people who, over a two-week period, were given a variety of breakfast meals. They wore wristwatches to record their physical activity and the quantity, quality, timing, and regularity of their sleep; keep a diary of their food intake; They recorded levels of alertness from the moment they woke up and throughout the day. Twins – identical and fraternal – were included in the study to separate the influence of genes from environment and behaviour.

What affects an individual's alertness from day to day

In the new study, Vallat, Walker, and their colleagues looked at the influence of genetics and non-genetic factors, including the environment, on alertness upon awakening. By measuring how alertness differed between individuals and in the same individual on different days, they were able to determine the role played by exercise, sleep, type of breakfast, and a person’s response to glucose after a meal. Credit: Rafael Vallat and Matthew Walker, UC Berkeley

The researchers found that the secret to alertness is a three-part prescription that requires a heavy workout the day before, sleeping longer and later in the morning, and eating a breakfast rich in complex carbohydrates, with little sugar. Researchers have also discovered that a healthy blood glucose response after eating breakfast is key to waking up more effectively.

“All of these elements have a unique, independent effect,” said Rafael Vallat, a postdoctoral fellow at the University of California, Berkeley, and first author of the study. “If you sleep longer or later, you will notice an increase in your alertness. If you do more physical activity the day before, you will see an increase. You can see improvements with each of these factors.”

Morning grogginess is more than just an annoyance. It has major societal consequences: many car accidents, work-related injuries, and large-scale disasters are caused by people who can’t shake their drowsiness. Well-known examples include the Exxon Valdez oil spill in Alaska, the Three Mile Island nuclear meltdown in Pennsylvania, and the even worse Chernobyl nuclear accident in Ukraine.

“Many of us think of sleepiness in the morning as a benign nuisance. Yet it costs developed countries billions of dollars each year through lost productivity, increased healthcare utilization and absenteeism,” said senior author Matthew Walker, professor of neuroscience and psychology at UCSD. California at Berkeley The most impactful thing is that it costs lives – it is fatal. From car accidents to work accidents, the cost of sleepiness is deadly. As scientists, we must understand how to help society wake up better and help reduce the deadly cost of society’s current struggle to wake up effectively every day “.

Vallat, Walker and colleagues recently published their findings in the journal

In contrast, the high carbohydrate breakfast — which contained large amounts of carbohydrates, as opposed to simple sugar, and only a modest amount of protein — was linked to individuals revving up their alertness quickly in the morning and sustaining that alert state.

“A breakfast rich in carbohydrates can increase alertness, so long as your body is healthy and capable of efficiently disposing of the glucose from that meal, preventing a sustained spike in blood sugar that otherwise blunts your brain’s alertness,” Vallat said

“We have known for some time that a diet high in sugar is harmful to sleep, not to mention being toxic for the cells in your brain and body,” Walker added. “However, what we have discovered is that, beyond these harmful effects on sleep, consuming high amounts of sugar in your breakfast, and having a spike in blood sugar following any type of breakfast meal, markedly blunts your brain’s ability to return to waking consciousness following sleep.”

It wasn’t all about food, however. Sleep mattered significantly. In particular, Vallat and Walker discovered that sleeping longer than you usually do, and/or sleeping later than usual, resulted in individuals ramping up their alertness very quickly after awakening from sleep. According to Walker, between seven and nine hours of sleep is ideal for ridding the body of “sleep inertia,” the inability to transition effectively to a state of functional cognitive alertness upon awakening. Most people need this amount of sleep to remove a chemical called adenosine that accumulates in the body throughout the day and brings on sleepiness in the evening, something known as sleep pressure.

“Considering that the majority of individuals in society are not getting enough sleep during the week, sleeping longer on a given day can help clear some of the adenosine sleepiness debt they are carrying,” Walker speculated.

“In addition, sleeping later can help with alertness for a second reason,” he said. “When you wake up later, you are rising at a higher point on the upswing of your 24-hour circadian rhythm, which ramps up throughout the morning and boosts alertness.”

It’s unclear, however, what physical activity does to improve alertness the following day.

“It is well known that physical activity, in general, improves your alertness and also your mood level, and we did find a high correlation in this study between participants’ mood and their alertness levels,” Vallat said. “Participants that, on average, are happier also feel more alert.”

But Vallat also noted that exercise is generally associated with better sleep and a happier mood.

“It may be that exercise-induced better sleep is part of the reason exercise the day before, by helping sleep that night, leads to superior alertness throughout the next day,” Vallat said.

Walker noted that the restoration of consciousness from non-consciousness — from sleep to wake — is unlikely to be a simple biological process.

“If you pause to think, it is a non-trivial accomplishment to go from being nonconscious, recumbent, and immobile to being a thoughtful, conscious, attentive, and productive human being, active, awake, and mobile. It’s unlikely that such a radical, fundamental change is simply going to be explained by tweaking one single thing,” he said. “However, we have discovered that there are still some basic, modifiable yet powerful ingredients to the awakening equation that people can focus on — a relatively simple prescription for how best to wake up each day.”

It’s not in your genes

Comparisons of data between pairs of identical and non-identical twins showed that genetics plays only a minor and insignificant role in next-day alertness, explaining only about 25% of the differences across individuals.

“We know there are people who always seem to be bright-eyed and bushy-tailed when they first wake up,” Walker said. “But if you’re not like that, you tend to think, ‘Well, I guess it’s just my genetic fate that I’m slow to wake up. There’s really nothing I can do about it, short of using the stimulant chemical caffeine, which can harm sleep.

“But our new findings offer a different and more optimistic message. How you wake up each day is very much under your own control, based on how you structure your life and your sleep. You don’t need to feel resigned to any fate, throwing your hands up in disappointment because, ‘… it’s my genes, and I can’t change my genes.’ There are some very basic and achievable things you can start doing today, and tonight, to change how you awake each morning, feeling alert and free of that grogginess.”

Walker, Vallat, and their colleagues continue their collaboration with the Zoe team, examining novel scientific questions about how sleep, diet, and physical exercise change people’s brain and body health, steering them away from disease and sickness.

Reference: “How people wake up is associated with previous night’s sleep together with physical activity and food intake” by Raphael Vallat, Sarah E. Berry, Neli Tsereteli, Joan Capdevila, Haya Al Khatib, Ana M. Valdes, Linda M. Delahanty, David A. Drew, Andrew T. Chan, Jonathan Wolf, Paul W. Franks, Tim D. Spector and Matthew P. Walker, 19 November 2022, Nature Communications.
DOI: 10.1038/s41467-022-34503-2

The study was funded by Zoe Ltd.

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