MONDAY, Jan. 9, 2023 (HealthDay News) -- Older women who don’t stick to a set sleep and wake schedule may be more likely to struggle with feelings of depression and anxiety — even if they get a normal amount of zzzs.

What’s more, a postmenopausal woman who goes to bed very early and wakes up very early (an “early bird”) or goes to bed late and wakes up later (a “night owl”) is 70% more likely to experience significant depressive symptoms — even with a normal amount of sleep, a new study suggests.

The study wasn’t designed to say whether sleep is the chicken, the egg, or both when it comes to mood. “It could definitely be the case that the women in our study who had depressive symptoms had a different type of sleep schedule because they were depressed, or that their depression was causing them to have more irregular sleep-wake patterns,” said study co-author Leslie Swanson. She is an associate professor of psychiatry at the University of Michigan, in Ann Arbor.

More research is needed to tease out the cause and effect between sleep and mood, particularly in postmenopausal women, Swanson said. “Women might be more prone to more irregular sleep patterns as they get older due to factors such as retirement from work or aging of the parts of the brain that control the timing of sleep,” she suggested.

“Even small changes in the timing of sleep, such as those caused by daylight saving time changes, can disrupt our circadian rhythms, which can, in turn, negatively impact factors that cause depression, anxiety and lower well-being,” Swanson said. Our circadian rhythm is the 24-hour internal clock that controls the release of the hormone melatonin to encourage sleep.

For the study, the researchers analyzed sleep patterns and assessed the psychological health of close to 1,200 postmenopausal women aged 65, on average.

Women with a sleep midpoint — the halfway point in clock time between falling asleep and waking up — that fell outside 2 and 4 a.m. were 72% more likely to report significant depression symptoms. Sleep midpoints determine if you are a morning lark or a night owl. If your sleep midpoint is 3:30 a.m. or earlier, you're probably a lark, and if it is 5:30 a.m. or later, you're likely an owl.

Each hour of sleep schedule irregularity increased in a woman’s chances of experiencing significant depressive symptoms by 68% and significant anxiety symptoms by 62%, the study authors noted.

Sleep was more irregular among Black women than among white, Chinese and Japanese women, the researchers found.

Getting regular, high-quality sleep is essential for physical and mental health, Swanson said.

Set an alarm clock for the same time every morning, seven days a week, even after retirement to make sure you wake at the same time every day and get into bright light as soon as you can after your alarm goes off, she advised.

Exposure to bright light sends a strong signal to your circadian clock about when you want to be awake and asleep, Swanson explained.

Take time to unwind before bed. “We’re not built to go from 60 mph to 0 mph when it comes to the transition to sleep,” she said. “Build in a buffer zone — free from work, social interaction, anything stimulating, including action/scary movies or books, Twitter, social media, etc. — starting 30 to 60 minutes before bed."

Also, try not to eat a large meal within three hours of bedtime. “Digestion will compete with sleep, and digestion wins just about every time,” she said. “Avoid sugar-laden foods a few hours before bed as insulin and cortisol spikes can disrupt sleep.“

The study was published online recently in Sleep Health.

Sleep affects your mental and physical health, agreed Dr. Rajkumar Dasgupta. He is an assistant professor of clinical medicine at the University of Southern California Keck School of Medicine.

“Previous studies regarding the irregularity of sleep have found that not sticking to a regular bedtime and wake-up schedule and getting different amounts of sleep each night can put a person at higher risk of medical problems, such as obesity, high cholesterol, hypertension and diabetes,” he said.

“The take-home message from this and other previous studies demonstrate that having a lack of a regular bedtime and wake-up schedule could have profound health effects, such as higher risk for depression and metabolic issues [such as obesity, high cholesterol, high blood pressure and diabetes],” Dasgupta said.

For folks with sleep or mood concerns, he suggested practicing meditation and mindfulness before bed.

“Being stressed can be a huge barrier from getting refreshing sleep. Being mindful and practicing meditation may help you sleep better, improving both the quantity and quality of sleep," Dasgupta added.

Sleep problems are common in menopause and they may continue into the postmenopausal years, said Dr. Stephanie Faubion, medical director for the North American Menopause Society and director of the Mayo Clinic Women's Health Center. “A good proportion of women in their 60s and 70s are still having hot flashes and night sweats,” she said. Drenching night sweats can disrupt sleep.

“Whatever we can do to make sure we sleep well is important,” she said. In addition to practicing good sleep hygiene, older women should take steps to boost their mental health, including engaging in things they enjoy and maintaining strong social connections,” said Faubion, who also had no ties to the research.

See your doctor if you experience significant mood or sleep changes as you age, she added.

More information

The North American Menopause Society provides more on sleep and menopause.

SOURCES: Leslie Swanson, PhD, associate professor, psychiatry, University of Michigan, Ann Arbor, Mich.; Stephanie Faubion, MD, medical director, North American Menopause Society, and director, Mayo Clinic Center for Women's Health, Rochester, Minn.; Rajkumar Dasgupta, MD, assistant professor, clinical medicine, Keck School of Medicine, University of Southern California, Los Angeles; Sleep Health, Dec. 9, 2022, online