That means people who enjoy rising early will be more aligned with their workday and likely to achieve more. One in four of us, though, are night owls Credit: Getty Images. Because the cultural stereotype is that people who go to bed and rise late are lazy, most people probably try to become morning people as much as they can.
But there may be a connection to genetics. Being a 'morning person' can be forced, but late-sleepers who set early alarms aren't necessarily any happier or productive Credit: Getty Images. Morning exposure to bright or natural light, avoiding artificial light at night and carefully-timed melatonin intake can help.
And because night owls tend to have a longer circadian cycle, putting them even more at odds with a hour schedule, that can be tougher for them to achieve. In real terms? Even that will require significant external input — like super-bright morning light at least 2, lux , she says.
To comment on this story or anything else you have seen on BBC Capital, please head over to our Facebook page or message us on Twitter. If you liked this story, sign up for the weekly bbc. Share using Email. By Amanda Ruggeri 15th November If she had it her way, she'd fall asleep around 3 am and wake up around noon. And it was none of those things. For Amy, a year-old Seattle resident, being a delayed sleeper means "there's a lot of emotional baggage tied up into going to work," she says.
They're closer to So every day our body clocks need to wind backward by just a little bit to stay on schedule. For the most part, the sun takes care of this. Exposure to bright light stimulates the brain's master clock — the suprachiasmatic nucleus — to wind back those three-tenths of an hour. Every single cell of the body has clock genes, bits of DNA that flip on and off throughout the day.
Like the body as a whole, the cell's metabolism is scheduled for efficiency. Clock genes regulate the expression of between 5 and 20 percent of all the other genes in the cell. The expression of these genes is believed to feed back into the body's master clock and help set its time. Scientists have found that small variations in these genes lead to earlier or later rhythms in animals , and are beginning to identify the genes that cause the same effects in humans.
Because it's genetic, chronotype is inheritable: Twin and heredity studies have found that about half the difference in chronotypes can be explained by genetics.
One thought is that evening-type people may have a body clock that runs longer than average. Evening types' clocks can run as long as A longer clock means the suprachismatic nucleus has to work harder to make an adjustment.
When it fails to readjust, sleep times drift later and later into the evening. Bright light at any time of the day tells our bodies it's time to be awake. This wasn't a problem back in olden times, when the setting of the sun ended light exposure for the day.
In modern times, light from our computers and televisions pushes some evening-type people to stay awake longer. Once these chronotypes are set, they're frustratingly stubborn. The only exception is when we age. As the decades pass, our clocks tend to shift earlier.
Scientists have a term for being out of sync: social jet lag. In a tightly controlled lab study, 24 healthy participants who had their sleep shifted by one hour each day simulating jet lag started to look prediabetic after a three week trial.
Their resting metabolic rates dropped 8 percent. When people experience social jet lag, they'll often try to make up for the sleep debt on the weekends. But this too is jarring for the body and makes waking up on Monday all the more difficult. In , researchers in Europe analyzed a self-report data set of 65, Europeans and found "social jet lag significantly increased the probability of belonging to the group of overweight participants.
A study tracking the sleep of middle-aged adults for a week also picked up on this worrisome pattern. It found social jet lag correlated with insulin resistance — a precursor to diabetes — lower HDL cholesterol the good kind , higher levels of triglycerides, higher waist circumference, and higher BMI. These correlations remained even after adjusting for behaviors like exercise, smoking, and alcohol use.
She also stressed that these were exploratory correlational studies. More rigorous testing is needed to confirm the link. If late sleepers want to wake up early, they're often hit with a double whammy. They'll be out of sync with society — which stresses the body — but they'll also be underslept. The research is a bit clearer on this: Short sleep appears to be a significant risk factor for heart disease, diabetes, and obesity.
In the academic literature, short sleep has been associated with higher blood pressure , body mass index, and increased calcification of the coronary artery. In lab experiments, people who slept only five hours a night for one week became less sensitive to insulin, which makes it harder to maintain blood sugar levels.
In an overnight sleep study of 1, individuals, poor sleep was associated with the misregulation of the hunger hormones leptin and ghrelin, which would explain another finding: that when people are denied sleep , they have increased appetite. But they require constant vigilance and are hard to maintain. The first — and easiest — is a combination of bright light therapy and melatonin. Exposure to bright light in the morning helps reset the body's clock to an earlier time. Patients can buy specialty lamps for this, or just make an effort to go outside early.
Sleep researchers recommend that you limit caffeine and alcohol close to bedtime and eat your largest meal earlier in the day. Studies show that you can use exercise to move your sleep phase earlier in the evening. In a recent study that tracked the exercise patterns and sleep cycles of 52 participants, people with an evening chronotype could advance their sleep cycle to an earlier time of day by exercising either in the morning or in the evening. The more entrained your sleep patterns are, the longer it may take to revamp them.
In the long run, that consistency will deliver better results. For many people, waking and sleeping cycles shift more than once in a lifetime. One big alteration in your chronotype typically occurs during the teen years. For teenagers, the onset of puberty marks a big shift toward a later sleep phase preference that lasts at least five years.
Research also indicates that the hormonal changes of pregnancy often move women to an earlier chronotype, at least during the first two trimesters. Women in a study reverted to their original sleep patterns toward the end of the pregnancy. A large Brazilian study involving 14, volunteers found that women tend to be more morning-oriented early in life, becoming more evening-oriented after the age of 45, as the amount of estrogen in the body decreases.
Most men in the study were late risers beginning at puberty. Many of the men became the up-at-dawn type with hormonal changes later in life. One pilot study indicated that both the severity of the stroke and the area of the brain affected could cause a significant change in chronotype. For people in this study, the changes lasted for at least three months after the stroke occurred. Seasonal changes can also influence how early you rise and how late you sleep. Daylight, one of the most powerful influences on your internal circadian rhythm, changes with the seasons.
Researchers think people have varying levels of sensitivity to changing seasons. Those who are highly sensitive to seasonal shifts may experience changes in their chronotype that enable them to adapt their sleep cycles and make the most of the daylight hours. Even the latitude of your home influences your circadian rhythms. Wide-ranging studies have shown that evening-ness is more common in places where the sunset occurs later in the day, and that people tend to be more morning-oriented in geographies closer to the equator.
Welcome to the era of chronotype diversity. In some workplaces, new management practices aim to create teams that recognize the contributions of people with differing chronotypes.
As remote work, flex scheduling, and virtual classrooms become more common, the morning imperative may begin to shrink in significance. It may take time to make the change, and you may revert to your genetically-set chronotype at some point in your life, but there are steps you can take to become more of a morning person now.
Diet and exercise can help you adjust your sleep schedule.
0コメント