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Sleep, exercise or diet? 1 factor was most linked to better mental health

Of “three pillars of health," one stood out when it came to predicting well-being.
Just one sleepless night can trigger up to a 30% rise in anxiety levels, separate research found.
Just one sleepless night can trigger up to a 30% rise in anxiety levels, separate research found.TODAY Illustration / Getty Images
/ Source: TODAY

The mental health toll just keeps growing. After a year filled with fear over the coronavirus, 2021 is starting with more anxiety about COVID-19 and the violence in Washington.

What can you do to help keep stress and depression at bay?

A recent study offers clues.

Getting quality sleep, exercising and eating more raw fruits and vegetables — in that order — predicted better mental health and well-being in young adults.

They can be thought of as “three pillars of health,” said Shay-Ruby Wickham, a graduate student at Otago Medical School at the University of Otago in Dunedin, New Zealand, and lead author of the study published in Frontiers in Psychology.

Sleep quality beat the amount of sleep a person got each night as the strongest factor in good mental health.

“This is surprising because sleep recommendations predominantly focus on quantity rather than quality,” Wickham said in a statement.

“While we did see that both too little sleep — less than eight hours — and too much sleep — more than 12 hours — were associated with higher depressive symptoms… sleep quality significantly outranked sleep quantity in predicting mental health and well-being.”

Just one sleepless night can trigger up to a 30% rise in anxiety levels, according to separate research from the University of California, Berkeley.

For the new study, Wickham and her colleagues asked more than 1,100 adults 18 to 25 years old to fill out a survey measuring how much and how well they slept, how often they exercised and what their diet was like — including how many raw fruit and vegetables they ate in a typical week.

Next, the participants filled out questionnaires designed to gauge their mental health, including whether they felt depressed or believed they were flourishing in life. They also shared their health conditions and whether they took antidepressants.

After analyzing the answers, the researchers found:

Sleep quality and quantity were the strongest lifestyle predictors of depression: People who had better sleep quality, and those who slept inside the range of eight to 12 hours per night reported fewer symptoms of depression. Sleep quality “significantly outranked” other health behaviors linked to mental health and well-being, the study noted.

Inadequate physical activity was the second-strongest predictor of depression: The study didn’t specify how much exercise was optimal, but the Centers for Disease Control and Prevention recommends doing at least 150 minutes a week of any activity that gets the heart to beat faster.

Eating raw fruits and vegetables “significantly” predicted flourishing: The sweet spot seemed to be about five servings per day. Cooked or processed fruits and vegetables weren’t as beneficial. Flourishing meant agreeing with statements such as, “I lead a purposeful and meaningful life” and “I am engaged and interested in my daily activities.”

The study's findings were correlations only, the authors noted.

How to get good quality sleep:

For the study, quality sleep was defined by feeling refreshed after waking up. How do you help make that happen?

Sleep experts offered these tips:

Stick to one sleep schedule: Keep the same bedtime and wake-up time, even on the weekends. This keeps your circadian rhythm consistent and makes it easier to fall asleep, said Michael Breus, a clinical psychologist and a fellow of the American Academy of Sleep Medicine.

Avoid caffeine after 2 p.m.: The stimulant can impact your body for six to eight hours after it's ingested, so if you stop in the early afternoon, its effects will stop at around 10 p.m., when most people start getting sleepy, Breus said. If you drink it later, you can still fall asleep but the quality of your slumber will be affected, he noted.

Don’t drink alcohol right before bed: Alcohol may make you feel sleepy, but it keeps you out of the deeper stages of sleep. Wait one hour per alcoholic beverage before going to sleep, Breus advised.

Don’t eat too late: Finish eating meals two to three hours before bedtime, the National Sleep Foundation recommended. Otherwise, it may be hard to get quality sleep if your body is still digesting a big dinner.

Exercise is the best way to improve the quality of your sleep: Just don’t do it right before bedtime.

Limit screen time before bed: Put your phone and other devices in another room. You don’t need them while you sleep.

Get morning light: If you can, as soon as you wake up, get 15 minutes of sunlight, Breus said. It keeps your internal body clock and sleep-wake cycle running optimally. Cortisol, a stress hormone, has been linked to sleep disruptions, but "exposure to natural sunlight to the early part of the day literally translated to lower cortisol levels at night," said Shawn Stevenson, author of "Sleep Smarter."