Some experts say yes because evening types are vulnerable to health problems. Others say trying to overcome your natural tendencies can do more harm than good.
More than a third of American adults routinely fail to get the seven or more hours of nightly sleep that’s generally recommended for optimal health, the Centers for Disease Control and Prevention said last year. In some cases, biology may be to blame.
Everyone has an internal clock, or circadian rhythm, that regulates feelings of sleepiness and wakefulness over a 24-hour cycle. These patterns vary from person to person, however, which is why some people function best in the morning and others seem to have more energy late at night.
Those who fall into the “night owl” category—almost 20% of Americans, by some estimates—have a problem in that their internal clocks are out of sync with society’s external ones, which generally favor early start times for school and work. That mismatch can put them at higher risk for such health problems as obesity, diabetes and depression.
Considering the risks, should night owls try to adopt an earlier sleep pattern?
Some say there is an environmental component involved, so night owls with no job flexibility should give it a try. Others say trying to override your natural tendencies is extremely difficult and could do more harm than good.
Nathaniel F. Watson, a professor of neurology at the University of Washington in Seattle, co-director of the University of Washington Medicine Sleep Center and director of the Harborview Medical Center Sleep Clinic, says some night owls would benefit by trying to change their sleep patterns. Katherine Sharkey, an associate professor and the assistant dean for women in medicine and science at Brown University’s Alpert Medical School, says going against your natural tendencies can do more harm than good.
YES: ‘Evening Types’ Are Susceptible to a Host of Serious Ailments
By Nathaniel F. Watson
The well-known proverb “Early to bed and early to rise makes a man healthy, wealthy and wise” appeared in Benjamin Franklin’s annual almanac in the mid-1700s, a time when bloodletting was commonplace in medical practice and the discovery of penicillin was nearly two centuries away. Yet this quip provides insight that, nearly 300 years hence, is germane to our discussion of health and human circadian rhythms, which are biological processes, such as the sleep-wake cycle, that persist in approximately 24-hour periods. Their fluctuations can be synchronized to the 24-hour day by environmental stimuli such as light.
In humans there is a wide range of circadian functioning, which is expressed as your “chronotype.” Evening types, or “night owls,” prefer to stay up late and go to bed in the early morning hours, functioning best at later times in the day or evening.
We are beginning to understand that being an evening type is bad for your health. Evening types have poorer diets, reduced quality of life and more depression, and they consume more alcohol than morning types. They also take longer to fall asleep and, perhaps most important, they sleep less.
The harsh reality is that modern society is hard on evening types. The 8 a.m. workday requires an early wake time, which, in turn, requires an early bedtime to allow for the seven or more hours of nightly sleep that is generally necessary for optimal health. Evening types don’t go to bed early; it isn’t in their nature. The end result is that evening types often end up chronically sleep-deprived, which is perilous to their health.
Chronic insufficient sleep is associated with cardiovascular disease, diabetes, obesity, impaired immunity, reduced performance, motor-vehicle accidents, poor mental health, pain and increased mortality. Clearly, we should strive to avoid these complications by prioritizing sleep in our lives, but simply ambling off to bed earlier isn’t an easy solution for evening types.
The most practical solution for evening types is to pursue careers with flexible hours. Evening types are only systematically sleep-deprived to the extent that they have an externally imposed early wake time. Left alone, evening types can have a happy and healthy “sleep life” with adequate nightly duration by just going to bed when tired and waking when rested, regardless of the time of day.
But for the majority of evening types who lack this flexibility, it is worth making changes to foster an earlier bedtime. While nearly half of what determines your chronotype is genetic in nature, the rest is environmental and modifiable, as shown in studies of twins.
Light is by far the most important factor that helps entrain, or synchronize, human circadian rhythms. To push to an earlier bedtime, evening types should get morning exposure to bright light, from ambient light or a therapeutic light box. And avoiding light in the evening is crucial for those seeking an earlier bedtime. This means that TVs, smartphones, tablets and laptops must be put away at an earlier hour.
Morning exercise is helpful, as is a regular bedtime routine that signals to the body that sleep is imminent. Bedtimes and wake times must be consistent: Just as a diabetic can’t eat a dozen doughnuts, evening types who want an earlier bedtime can’t have an erratic sleep schedule. Taking melatonin a few hours before the intended bedtime also can help some people, but it shouldn’t be necessary long-term.
Advancing bedtimes for evening types isn’t easy, but for most it is necessary to reap the benefits of adequate, regular sleep duration, which is a prerequisite to a healthy life. For evening types pursing this goal, the wisdom of Benjamin Franklin again provides insight, in that “energy and persistence conquer all things.”
Dr. Watson is past president of the American Academy of Sleep Medicine, a professor of neurology at the University of Washington in Seattle, co-director of the University of Washington Medicine Sleep Center and director of the Harborview Medical Center Sleep Clinic.
NO: Trying to Change Sleep Patterns Can Do More Harm Than Good
By Katherine Sharkey
Sleep patterns are determined mainly by core biological factors, and attempting to oppose the internal clock can increase health risks.
“Circadian rhythms” refer to the internal biological clocks that regulate our physiological processes (hormone release, kidney and liver function, etc.) and behaviors (things like sleeping and eating) to optimize living according to the 24-hour light-dark cycle here on Earth.
Science has shown that each cell in our body has a clock mechanism that helps our various organs keep time, and that these “peripheral clocks” are governed by a master clock in the brain called the suprachiasmatic nucleus, or SCN for short. When things are working well, the SCN keeps all of the other body clocks synchronized. It responds precisely and predictably to the 24-hour patterns of light and dark to orchestrate the alignment of all of the downstream peripheral clocks.
The main sleep period of the day communicates potent information about the light-dark cycle to the SCN. The light at wake time helps synchronize circadian rhythms, including the timing of sleep on the subsequent night. From a health standpoint, the ideal time to sleep is during the “biological night,” or when all of a person’s clocks are coordinated and fulfilling their usual nighttime activities.
For night owls, this “sweet spot” for sleep occurs at a later time than for early birds, and this internal timing is mainly governed by biological factors that aren’t modifiable.
Age is one of the best-characterized and strongest determinants of whether an individual’s biology follows that of a morning lark or a night owl. Prof. Till Roenneberg of Ludwig-Maximilian University in Munich has shown a significant peak in night-owl tendencies during the teens and early 20s. A person’s sex also plays a role—research shows men are more likely to be night owls than women—as do certain genes that have been shown to contribute to night-owl propensity.
In contrast, sleep habits contribute less toward an individual’s predisposition to being a night owl. Unfortunately, resetting our internal clocks isn’t as easy as changing the time on a watch or the clock on a wall. And when sleep patterns and other light-dark cues don’t occur at predictable/expected times, this leads to desynchronization of the body clocks.
Numerous studies have demonstrated that desynchronized rhythms are associated with negative health consequences, including disrupted and shortened sleep, problems with mood regulation, metabolic abnormalities that increase risk of obesity and diabetes, cognitive dysfunction and even increased cancer risk.
Although bright light exposure through light boxes and outdoor light can help resynchronize misaligned clocks, it is very difficult to overcome the underlying biological factors of being a night owl, especially long term. Melatonin and medications that mimic it have some efficacy for realigning circadian rhythms, and while they are an important option for those with debilitating circadian-rhythm sleep-wake disorders, there is no evidence that their use is suitable or safe to treat the “normal variant” of being a night owl.
The reality is, people who try to change their natural sleep patterns often end up getting less sleep or poor-quality sleep. Many night-shift workers, for example, live with chronic circadian desynchrony because their bodies never fully adapt to working at night and sleeping during the day. Indeed, shift work is associated with so many negative health consequences that in 2007, the World Health Organization classified night-shift work as a probable carcinogen due to circadian disruption.
So, what is a 24-hour society to do to minimize the health risks of circadian desynchrony?
Solutions include the adoption of flexible schedules that allow people to work during their individual circadian daytime if possible. Education policy should acknowledge the strong preponderance of night owls among teens and young adults and schedule school start times to align with this known biology to reduce the number of young adults living in a perpetual state of circadian misalignment. More research on countermeasures like melatonin and light is needed to determine best practices and whether such interventions are safe. Finally, increasing education about circadian rhythms and sleep will help individuals keep track of how their sleep patterns affect their health.
Dr. Sharkey is an associate professor and the assistant dean for women in medicine and science at Brown University’s Alpert Medical School.