How sleep impacts your mood

The effects of a good (or bad) night’s rest on how you feel.
Published November 3, 2020

Have you ever been in a bad mood and wondered why? It may have been tied to how well (or rather, how poorly) you slept the night before.

“Sleep and mood are intimately connected,” says Monisha Bhanote, MD, FCAP, a triple board-certified physician and Yoga Medicine® teacher. “True restful sleep can improve well-being, while poor, inadequate sleep may cause irritability, moodiness, and make you vulnerable to stressors. This also is observed in the opposite direction, where mental stress, mood and anxiety affect sleep by keeping the body aroused. In fact, individuals with sleep problems tend [to have] exaggerated responses to stress.”

Bhanote points out that “Researchers at the University of Pennsylvania found that individuals who limited their sleep to 4.5 hours per night for a week displayed [feelings of being] stressed, angry, sad, and mentally exhausted. When they resumed adequate sleep hours, their mood improved dramatically.”

“Sleep definitely can impact your mood, hence the colloquial saying, ‘woke up on the wrong side of the bed,’” adds Dr. Kent Smith, president of the American Sleep and Breathing Academy and founding director of Sleep Dallas, a dental sleep medicine practice that provides oral appliance therapy to patients with sleep apnea.

“According to the National Center for Biotechnology Information,” he adds, “brain activity during sleep has been found to have an overwhelming effect on a person’s emotions and mental health.”

Smith explains, a lack of sleep is harmful to the process of reinforcing the positive emotions you experienced throughout the day. When you’re sleeping, your brain is remembering and evaluating all the thoughts and memories you had throughout the day, he says. “When your sleep is disrupted or overall poor in quality, it can influence your mood and emotional reactivity.”

The quality of your rest is linked to the different stages of sleep, and how much time you spend in them.

Smith breaks the stages down for us:

“During sleep, there are four different stages a person goes through, three non-rapid eye movement (REM) and one REM stage.”

Stage 1 or N1: Dozing off, brain and body activities start to slow; one-minute to five-minute intervals.

Stage 2 or N2: More relaxed state, body temperature drops, breathing slows, new brain wave pattern, eye movement stops; 10-25 minutes when directly following N1, but between 10-60 minutes when following an N3 or REM stage. “A person spends about 50 per cent of their time asleep in the N2 stage,” Smith says.

Stage 3 or N3: Deep sleep, pulse and breathing rate decrease, the body relaxes even further, critical for body recovery and growth; 20-40 minute intervals.

Stage 4 (REM): Brain activities pick up, vivid dreams, temporary paralysis with two exceptions: the eyes and the muscles required for breathing; 10-60 minute intervals.

“Each sleep stage allows for activity in different parts of the brain at different times throughout the night, which leads to better thinking, learning, and memory,” Smith says. “Getting enough sleep, specifically REM sleep, helps the brain deal with emotional information.”

Licensed psychologist Dr. Rebecca Leslie, PsyD points out that sleep deprivation is also associated with depression and anxiety.

And on the flip side, as Bhanote noted, your mood can also affect your sleep – such as if you are constantly worried about getting a good night’s rest.

Leslie explains: “If you are lying in bed worrying about getting a good night’s sleep, chances are you will not be able to get a good night’s sleep.”

Tips to stop worrying about sleep – and sleep better

To ease your anxiety around sleep, Leslie says it may be helpful to remember times in the past when you haven’t slept well the night before but were still fine the next day.

Get to the root of it

It can also help to get to the root of your worry.

“It can be helpful to understand what about getting a good [night’s] sleep is making you worry. Are you worried you will sleep through your alarm, will fall asleep at work, will harm your health? See if you can identify that worry and then challenge it or problem solve for it. For example, if you are afraid you will sleep through your alarm, you can set several alarms as backup and tell yourself these alarms will wake me up even if I am very tired in the morning.”

Don’t watch the clock

“Do not clock watch and then do mental math about how much sleep you are not getting,” Leslie says. “Turn the clock away from you.”

Remind yourself it’s okay if you can’t fall asleep

“Remind yourself if you do not sleep that is okay, and see if you can accept it,” says Leslie. “Let go of the struggle and say something to yourself like, ‘Okay, my body just doesn’t want to sleep tonight, let me use this time to do something else.’ If you are not able to sleep, instead of lying there worrying about it, use that time to do something that is relaxing and you will enjoy. For example, catch up on a good book or show (with the brightness dimmed). When you are sleepy, then you can try to fall back to sleep again.”

Find some Zen

Leslie also suggests trying a meditation or listening to a sleep story to relax. Check out Headspace in the WeightWatchers® app for some options.

Develop a sleep routine

And last but certainly not least, to ensure good quality sleep it can be helpful to have a sleep routine. Leslie says the “routine” part is key.

“I think it is helpful to have a bedtime routine, meaning doing a similar thing every night that signals to your brain and body it is time to wind down and prepare for going to bed,” she says. “This can vary person to person. Some ideas are brushing your teeth then reading a book, putting your blanket into the dryer to warm it up and then watching a show (make sure the brightness is on the lowest setting).”

She adds that a healthy sleep routine also involves trying to go to bed and wake up around the same time every day.