Resetting The Bodys Clock
In collaboration with Jamie Zeitzer, PhD, associate professor of psychiatry and behavioral sciences at the medical school and at the Veterans Affairs Palo Alto Health Care System, Heller has also been studying more basic questions about circadian rhythms in people and how to change these rhythms. The easiest way to alter the circadian clock, scientists know, is by exposing someone to light during their normal sleeping hours. This more quickly shifts the bodys clock than exposure to darkness during the waking hours.
Typically, researchers thought someone had to be exposed to at least half an hour of constant light to shift the clock, says Heller.
But if youre on a plane with the lights out, working nights or arrive in a new time zone after the sun has set, it might not be possible to get this half-hour of light to get your clock on the right schedule. So Heller and Zeitzer started investigating whether shorter bursts of light could do the trick. In both human and mouse studies, theyve now shown that 2 millisecond flashes of light every 30 seconds for an hour during the night while it doesnt interrupt sleep can make people wake up earlier in the morning, shifting their circadian clock by almost an hour. The finding could lead to the development of new devices to help people avoid jet lag or adjust to a new shift at work.
If It Feels Like Midnight This Must Be Paris
Jet lag occurs when your bodys internal clock is out of sync with the current time zone.
If you’ve ever traveled by plane across several times zones, chances are you’ve experienced “jet lag.” Symptoms of jet lag may include excessive daytime sleepiness, nighttime insomnia, headache, loss of appetite, gastrointestinal problems, and irritability or mild depression.
Can You Change Your Circadian Rhythm
The human body follows an internal timekeeping system known as a circadian clock. This internal clock regulates the bodys natural circadian rhythm, your daily cycles of sleep and wakefulness, hunger and digestion, hormonal activity, and other bodily processes. The word circadian comes from the Latin phrase circa diem, meaning about a day, referring to how most circadian rhythms automatically reset every 24 hours. Circadian rhythms are guided by natural signs that you should be awake like light exposure, interaction with people, and planned meal times. However, once set, circadian rhythms can be quite difficult to change, preserving the rhythm without any exposure to the typical signals.
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Problems With Circadian Rhythms
Generally, and for most people, our circadian cycles are aligned with the outside world. For example, most people sleep during the night and are awake during the day. One important regulator of sleep-wake cycles is the hormone melatonin. The pineal gland, an endocrine structure located inside the brain that releases melatonin, is thought to be involved in the regulation of various biological rhythms and of the immune system during sleep . Melatonin release is stimulated by darkness and inhibited by light. People rely on zeitgebers, or external cues, such as light, atmospheric conditions, temperature, and social interactions, to set the appropriate biological clock
There are individual differences with regards to our sleep-wake cycle. For instance, some people would say they are morning people, while others would consider themselves to be night owls. These individual differences in circadian patterns of activity are known as a persons chronotype. A persons individual chronotype may show that a person has a greater propensity to sleep earlier and wake up earlier , or to stay up late and sleep in . Morning larks and night owls differ with regard to sleep regulation . Sleep regulation refers to the brains control of switching between sleep and wakefulness as well as coordinating this cycle with the outside world.
Strategies For Sleeping Better
There are a variety of ways to cope with the sleep problems caused by rotating work shifts and ongoing night work. The approach that will help you the most depends on the following three factors:
- Your individual needs
- The requirements of your job
- Your environment at home
Some methods will apply to your situation more than others. For example, working rotating shifts in a hospital may require a different approach than working the night shift on an assembly line. Also, some people respond to shift work better than others. In general, older people find it harder to work nights or to rotate shifts. Your personality may also suit you better for one kind of shift. Some people are “evening types.” They like to go to bed late and sleep late in the morning. They feel most alert and energetic in the evening. They may adjust to the night shift better than “morning types.” Morning types wake up early and work best in the morning. They get tired and go to bed early in the evening.
From the options below, find what will work best for you in your situation. The most important thing you can do at first is to make sleep a high priority in your life.
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Examples Of Rhythms Relevant To Human Disease
Some examples of human rhythms in disease processes include night time asthma, early morning increases in blood pressure, death rate from cardiovascular disease and stroke, disrupted menstrual cycles, abnormal cortisol rhythm in Cushing’s syndrome, sleep disorders for example delayed sleep phase syndrome, advanced sleep phase syndrome, non-24 h sleep wake cycles , some psychiatric disorders. Numerous aspects of human biochemistry show rhythmicity, even urinary creatinine. Thus diagnostic tests should be aware of these rhythms. Measurement of a given rhythmic variable in someone who has just crossed several time zones, or worked a series of night shifts, can give false-negative or false-positive results. Moreover, many drugs have a rhythmic variation in both pharmacokinetics and efficacy .
How It Affects Your Health
Circadian rhythms affect your sleep-wake cycle, eating habits, body temperature, digestion, hormone levels, and other body functions. Because of this, your body’s internal clock can play an important role in your overall health. Interruptions to your circadian rhythm may contribute to health conditions including diabetes, seasonal affective disorder, and sleep disorders.
Fortunately, understanding how these cycles influence your health can help you address potential problems and seek treatments that can help. For example, you can make lifestyle changes that can help get your circadian rhythm back on track. Your doctor can also help you address conditions that might be affected by your body’s natural rhythms and come up with treatments that involve both medication and lifestyle adjustments.
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What Youll Learn To Do: Describe Consciousness And Biological Rhythms
Are you tired? Have you ever pulled an all-nighter? How did you feel the next day? Do you think your lack of sleep impacted your behavior? Chances are, you could answer that question with a resounding, yes!. Because psychologists are interested in mental processes and behavior, its essential to study consciousness, or our awareness, as humans. States of consciousness vary over the course of the day and throughout our lives, and sleep plays a major role in alertness levels. Important factors in daily changes in consciousness are biological rhythms, and, more specifically, the circadian rhythms generated by the suprachiasmatic nucleus. Typically, our biological clocks are aligned with our external environment, and light tends to be an important cue in setting this clock. When people travel across multiple time zones or work rotating shifts, they can experience disruptions of their circadian cycles that can lead to insomnia, sleepiness, and decreased alertness. If people go extended periods of time without sleep, they will accrue a sleep debt and potentially experience a number of adverse psychological and physiological consequences.
Sleeping Against The Clock
A main challenge of shift work is that it forces you to sleep against the clock. You have an internal body clock in your brain that produces circadian rhythms. The word “circadian” means to occur in a cycle of about 24 hours. These rhythms act like “messages” that regulate various body functions. They influence such things as the following:
- Body temperature
- Hunger
- Hormone Levels
Your body clock uses these rhythms to signal to you when it is time to go to sleep or to wake up. This tends to occur at regular times every day. Among other factors, your clock is “set” by your exposure to sunlight. This keeps the clock’s timing close to the night/day cycle. In most adults, circadian rhythms cause your level of sleepiness to peak from aboutmidnight to 7 am. They can also make you mildly sleepy in the mid-afternoon between 1 pm and 4 pm. If you work at night, you must fight your body’s natural rhythms to try and stay awake. Then you have to try to sleep during the day when your body expects to be alert.
Some researchers think that it may take as long as three years to adjust to a shift work schedule. Others believe that you will never fully adjust to an unusual sleep/wake pattern. Even if this is the case, you can make the best of a bad situation to sleep better.
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The Best Time For Activities
The reality is that the demands of daily life such as school, commuting, work, and social events can all throw the body’s natural cycles out of whack. The way we organize our daily activities is sometimes in direct contrast to our body’s own inclinations.
Altering your schedule might not always be easy, but there are clear benefits to doing so. In addition to making better use of your time, there are also potential health implications. Circadian rhythm disruptions have been linked to a range of negative health outcomes including depression and diabetes.
When is the best time to tackle certain tasks?
Importance Of Biological Rhythms To Health
Biological rhythms serve to align our physiological functions with the environment. We are a diurnal species and thus, we normally sleep at night and are active during the daytime. The timing of functions with prominent rhythms such as sleep, sleepiness, metabolism, alertness and performance in a normal environment is such that they are optimal during the most suitable phase of the day . Abrupt deviations from normal timing of work and sleep can lead to problems, for example sleep taken during the day is usually shorter and of worse quality than when taken at night . Alertness and performance reach their nadir at night during peak sleep propensity and fatigue and close to the low point of core body temperature and the peak of melatonin secretion. The health problems and increased risk of major disease in long-term shift workers are ascribed largely to working out of phase with the internal biological clock. It is likely that many perceptions of the detrimental effects of clock disruption or abnormal timing derive from observations in shift workers.
Diagrammatic examples of circadian rhythms, from Rajaratnam and Arendt, Lancet 2001 , by permission.
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Reset Your Circadian Rhythm To Get Your Sleep Back On Track
There are many reasons you might want to reset your circadian rhythm. Maybe staying up late on the weekends â or an otherwise erratic sleep schedule â is diminishing your weekday energy levels. Or perhaps shift work or jet lag has thrown your sleep schedule out of whack. Even the twice-yearly one-hour time change around daylight saving time can be enough to leave you feeling out of sorts. In fact, any ongoing sleep problems or daytime sluggishness could potentially be signs of circadian misalignment.
No matter what the cause, circadian misalignment can make you feel drained and can have serious health consequences. The good news? A circadian reset can help. But thatâs only part of the equation. In order to feel good and perform at your best each day, you must also get sufficient sleep and keep your sleep debt low.
In this article, weâll explore the inner workings of your internal clock, or circadian rhythm. Weâll also discuss the importance of good sleep hygiene â the upkeep of behaviors that influence the way you sleep â and how you can adjust your daily habits to restore your circadian alignment for better sleep and better days.
Melatonin Indicates The Timing Of The Biological Clock
Shifts in the timing of melatonin are considered to represent changes in timing of the central clock. Measurement of melatonin in plasma, saliva or its urinary metabolite 6-sulphatoxymelatonin provides the best peripheral measure of central clock timing . Other marker rhythms such as core body temperature and cortisol are more subject to so-called masking, whereby an internal or external influence distorts the rhythm. For example, exercise and food strongly influence core temperature and stress modifies the cortisol rhythm. The most reliable results regarding circadian status in shift work have been obtained with melatonin measures and this review will concentrate on melatonin-derived information.
Characteristics of the melatonin rhythm used to define timing of the internal clock. From by permission.
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Why Your Circadian Rhythm Matters
Your circadian rhythm affects all aspects of your life, says Dr. Roth.
For example, if your sleep times are off, your hunger could be off or your eating times, says Dr. Roth. We often see people who are sleep deprived that their hunger changes, either goes up or down and the timing of when they get hungry can change.
Reset Your Circadian Rhythm With Rise
In todayâs world, itâs all too easy to get caught up in the hectic pace and endless demands that often dominate our lives. You might even be too busy to notice that you could be suffering from circadian misalignment. But if youâre having trouble sleeping or feeling especially run down, it might be time for a reset.
Adopting good sleep hygiene habits â with special emphasis on the timing of your light exposure â and making incremental sleep schedule changes can help you get closer to your ideal biological bedtime and wake time.
But tuning into the specifics of your circadian rhythm isnât exactly second nature. The RISE app is a convenient tool that simplifies and streamlines the process of maintaining or resetting your circadian rhythm. It replaces uncertainty and guesswork with automatic calculations and an easy-to-use interface. RISE uses special algorithms and your recent sleep history data to estimate your personal daily energy cycles to give you an ideal bedtime and wake time, insights about daily energy peaks and dips, and helpful reminders for maintaining good sleep hygiene.
Getting a clear picture of your circadian rhythm is a game changer. When you can see the signs of circadian misalignment as soon as they begin to develop, you can move quickly to make the changes needed to reset your circadian rhythm â before you lose too much sleep over it. After all, getting the sleep you need is the key to feeling and being your best every day.
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Jet Lag And How To Mitigate Its Effects
Dennis Dean describes how jet lag affects the body and suggests ways to minimize the negative effects.
Of all the environmental cues, light is the most powerful synchronizer of our internal biological clock. It is the cue for the body to know when it should be awake and active. It is difficult to predict what new schedule an individual should adopt in order to minimize the effects of jet lag. It depends on many factors: the time of day of travel, the speed, distance, and direction of travel, the persons internal clock time, the persons habitual sleep/wake schedule, and the light/dark schedule.
Sunlight is one of the main cues for the body to know when it should be awake or asleep.
Lights Out For Best Sleep
Indoor lighting and electronic devices that emit light like computers, tablets, smartphones, and TVs are relatively new to the realm of human experience. For the vast majority of time in history, humans were not exposed to these amenities. Historically, humans got up when the sun rose and went to bed when the sun set. Now, we live largely indoors and are exposed to many sources of artificial light that interfere with our internal clock. Turn off or limit your exposure to devices for several hours before bed so they do not affect your internal clock. Dim indoor lighting in the evening so it is less likely to affect your biological rhythms. Establish a relaxing bedtime routine with light reading, taking a warm bath, or listening to soothing music to help you wind down.
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Laboratory Research On Unconscious Visual Processing
Dr. Tony Ro is a professor of psychology at the City University of New York. He started studying the connection between consciousness and brain processing more than 20 years ago, and he was one of the earliest researchers to apply TMS technology to the study of visual perception.
In one study, Dr. Ro and graduate students Jennifer Boyer and Stephenie Harrison used TMS technology to see if normal people could process features of visual stimuli without conscious awareness of those stimuli. In other words, they wanted to know if they could they create temporary blindsight in normal subjects in a laboratory.
Remember that blindsight involves unconscious awareness of features of objects and events, such as the shape of an object or the direction of its movement. This study focused on two visual features: orientation and color. You and I see orientation or color as part of the experience of some object. A line is horizontal. A box is red. For a person with blindsight, horizontal is experienced without any shape associated with it. Red is experienced without awareness of the thing that is red. This is the blindsight condition that Dr. Ro and his colleagues wanted to reproduce in the laboratory with the help of volunteer subjects.
Lets walk through the experiment to understand how it was designed and conducted.