With a new year underway, it might seem like a good idea to embrace a stricter morning routine of waking up early and getting a jump-start on the day - but a 6 a.m. alarm isn't for everyone, experts say.
"Morning birds" fall asleep and reach deep sleep earlier, often waking up more alert, while "night owls" naturally sleep later and rely more on late-night and early-morning REM. Waking too early can leave night owls groggy and less mentally restored.
"We need to move beyond the 'early bird gets the worm' sayings and consider the biological cost of fighting one's internal clock," Aaron Pinkhasov, M.D., chair of the Department of Psychiatry at NYU Grossman Long Island School of Medicine, told Fox News Digital.
INSUFFICIENT SLEEP LINKED TO MAJOR HIDDEN HEALTH RISK, STUDY REVEALS
People sleep in repeated 90- to 110-minute cycles that alternate between deep NREM sleep and REM sleep, according to Pinkhasov.
Early in the night, deep sleep dominates, supporting physical repair, immunity and memory. Later cycles include more REM sleep, which supports learning, emotional regulation and brain function. Brief awakenings between cycles are normal.
Whether someone naturally rises early or late depends on the body's "chronotype" - that is, whether they're a morning bird or a night owl, he said.
The chronotype is a "genetic blueprint" that determines when the body is naturally more alert or ready to rest, according to Pinkhasov.
"About 40% to 50% of our sleep-wake preference is inherited, meaning our internal clock is hardwired," he noted.
DID HOLIDAY STRESS WREAK HAVOC ON YOUR GUT? DOCTORS SAY 6 SIMPLE TIPS CAN HELP
Waking earlier than one's body's clock often means sacrificing REM sleep. Forcing this discrepancy between the internal clock and the alarm clock can lead to "wired but tired" fatigue, mood instability and long-term metabolic risks, Pinkhasov warned.
"Unfortunately, because a lot of people have early work, family or social commitments, night owls have a higher prevalence of anxiety, depression, eating disorders, obesity, obstructive sleep apnea and [type 2 diabetes]," Dr. Nissa Keyashian, a California board-certified psychiatrist and author of "Practicing Stillness," told Fox News Digital.
CLICK HERE FOR MORE HEALTH STORIES
Ultimately, health and productivity are highest when prioritizing consistency and sleep quality over an early-morning goal, experts say.
"The main benefit of switching to an earlier schedule is social alignment - it makes it easier to navigate a world built around a 9-to-5 lifestyle. However, the drawbacks can be significant if the shift is forced," Pinkhasov said.
There are some ways to "rewire" internal clocks or at least lessen the negative effects. Experts agree that having a regular bedtime and wake-up time - even on the weekends - can help.
CLICK HERE TO SIGN UP FOR OUR HEALTH NEWSLETTER
Pinkhasov recommends a wind-down nighttime routine that includes minimizing electronics, meditating, using essential oils, taking a warm shower or bath, or drinking warm, herbal tea.
Pushing up your wake-up time by just 15 minutes a day is the most helpful, according to Keyashian.
The expert also recommends exposure to bright light in the morning, which can be helpful for mood, energy and concentration. People who experience dips in mood during the winter months can also benefit from using a therapeutic light box.
TEST YOURSELF WITH OUR LATEST LIFESTYLE QUIZ
"If you believe this might be you, I recommend speaking with a psychiatrist," she advised. "I also recommend minimizing caffeine. Some people also notice difficulty falling asleep with exercise late in the day, so be mindful of this as well."
