Some people have been sleep deprived for so long that they don’t know what a normal sleep cycle feels like anymore. The average sleep cycle is anywhere from 90 to 110 minutes long. The best sleep cycle for you might be different for someone else. Your needs might even change from night to night.
The body is made of several internal clocks or processes that work together to set your natural rhythm. You can throw these natural processes off by staying up too late, eating the wrong foods, and being exposed to excessive amounts of stress. Here’s how to fine tune your sleep cycle so you can enjoy the best sleep possible.
Your natural sleep cycle is determined by the circadian rhythm or a 24-hour cycle that determines your eating and sleeping cues. All living things have one, including animals, fungi, and some bacteria. The circadian rhythm controls brain wave activity, cell regeneration, hormone production and other processes that keep you properly functioning. Although these cues are internal, they can be influenced by outside factors such as temperature and sunlight (1).
The circadian rhythm is not the same things as the biological clock, but they are related. The biological clock is responsible for regulating the circadian rhythm by interacting with molecules located in cells throughout the body (2). The master clock refers to a part of the brain that keeps track of all the processes in the body so that they work together.
The master clock is composed of a group of 20,000 nerve cells located in the hypothalamus of the brain known as the suprachiasmatic nucleus or the SCN (2). The hypothalamus is located above the optic nerves, which are responsible for transmitting light signals to the brain.
Some research suggests that your circadian rhythm is genetic. But while factors inside the body influence your circadian rhythm, it can also be affected by external factors. Light is the biggest environmental factor that affects the circadian rhythm. In fact, light is so powerful that can turn on or turn off genes in the body that determine your circadian rhythm (2).
The circadian rhythm is responsible for controlling your sleep-wake cycle, body temperature, and hormone production. Insomnia develops as a result of a circadian cycle that is out of sync. Dysfunctional circadian cycles have also been linked to other health problems such as depression, anxiety, bipolar disorder, obesity and seasonal affective disorder (2).
The circadian rhythm determines the quality and duration of your sleep. The SCN is responsible for producing melatonin, which is a hormone needed to make you feel tired. Because the SCN is located above the eyes, it sends messages to the brain when you are exposed to light. When you are not exposed to light, the SCN tells the brain to make melatonin so that you can fall asleep. On the other hand, when you turn the lights on, the SCN tells the brain to stop making melatonin so you can get on with your day.
You may notice that jet lag or traveling across several time zones throws off your circadian rhythm. As you arrive at your destination, your watch may tell you one thing, but your body’s internal clock is still set to the time zone you just came from. Staying up late or adjusting to your new sleep cycle is difficult and may take a few days, which can leave you feeling disoriented.
Researchers study circadian cycles by using models that have similar genes. They also use environmental factors such as alternating dark and light periods to determine how your sleep cycle is affected. In many cases, exposure to light and dark can alter your genes to change your sleep cycle.
Health experts recommend that most healthy adults get between seven to nine hours of sleep each night. But not everyone gets this. Nor do they sleep consistently through the night without interruptions. If you’re worried about always waking up in the middle of the night, don't worry! Some studies indicate this might be normal.
Research shows that a little bit of insomnia might be natural. One report shows that humans do not naturally sleep all night long except during low latitudes in the middle of the summer (3). The report indicates that your natural sleep cycle is bimodal, meaning that your sleep consists of two periods of sleep that are naturally interrupted in the middle of the night by a short episode of wakefulness (3).
A study conducted in the early 1990’s by Doctor Thomas Wehr of the National Institute of Mental Health investigated the sleep patterns of a group of healthy adults. The volunteers were placed in a dark environment for 14 hours each day for one month. They were allowed to sleep as much as they wanted for as long as they wanted.
Results found that by the fourth week, the volunteers were sleeping an average of eight hours a night but not all at once. Their sleep patterns were broken up into two segments. When they first went to sleep, most volunteers laid awake for up to two hours before quickly falling asleep. Dr. Wehr concluded that they quickly drifted off to sleep due to an increase in the hormone melatonin. After three to five hours of sleep, the volunteers would wake up and spend an average of one to two hours in a peaceful stage of wakefulness before sleeping for another three to five hours (3).
Bimodal sleep has also been observed in other studies with people who live in industrial societies that lack artificial light. Dr. Wehr has studied the sleep habits of hunter-gatherers in Africa and found that they drift in and out of sleep throughout the night possibly as a safety feature. According to Carol Worthman, an anthropologist at Emory University in Atlanta, there are some advantages to interrupted sleep. She stated that being solidly asleep makes humans vulnerable to predators, which may explain why we have natural tendencies to wake up in the middle of the night.
Artificial light has caused people to expand our daytime activities into the late night when all other animals are asleep. Because of this, humans have compressed their natural sleep cycle into shorter periods of sleep, but not everyone responds to stimuli the same way. Some people have stronger circadian rhythms than others and may revert to the bimodal sleep patterns that are often confused with a sleep disorder.
Under the pressures of modern life, many people have trouble falling asleep or staying asleep. But the principles of bimodal sleep shows that if you wake up in the middle of the night for an hour or two, there may be nothing wrong with you at all. You may just be a natural sleeper. The key is to determine if your middle of the night wake up call is causing you more harm than good.
Although a little nighttime wakefulness can be normal, chronic insomnia is bad for your health. If you have problems falling asleep and staying asleep, you’re probably one of the 70 million Americans that suffer from insomnia. Your body undergoes many important processes during sleep. Chronic sleep loss robs your body of the time it needs to repair itself. It also puts you at an increased risk of many diseases.
After thousands of years of being exposed to the predictable pattern of day and night, your genes have regulated themselves to work in tune with nature. But modern life keeps us awake late at night working or watching television, which causes an imbalance between your natural genetic composition.
Humans once depended on cues from the sun to determine when we should go to bed and wake up. But now we spend more time indoors with artificial light than we do outdoors with natural light. We wake up long before the sun comes up and we go to bed well after it’s dark. It’s no wonder why our natural sleep cycle is all messed up. We’re sending it mixed signals!
Although insomnia is an individualized condition that should be treated as such, there are many things you can do to synchronize your circadian cycle. In a fast paced world, the best thing you can do is to regulate your exposure to darkness and light, change bad behaviors, balance your hormones, and calm the nervous system to prepare it for sleep. Here are some tips to naturally synchronize your sleep cycle.
Start by perfecting your wake up time. Some research suggests that if you need an alarm clock to wake up, you’re not sleeping right. Instead, try a dawn stimulating device that helps you wake up naturally through exposure to daylight. It’s also a much more pleasant thing to wake up to than a loud and abrupt alarm!
It’s not just what you do at night that affects how you sleep. Your daytime activities also play a role. Taking five-minute breaks throughout the day can help alleviate stress so that it doesn’t build up. If you’re at work, close your office door or find a quiet spot where you can take a few deep breaths or meditate.
It may also be helpful to take natural supplements that have a calming effect on the mind about 30 minutes before bed, such as melatonin, tryptophan, magnesium, l-theanine, GABA, passion flower, chamomile and valerian root. Lavender oil and other calming scents can be used in baths. You can even spray lavender essential oil on your pillow or sheets to help you stay calm throughout the night.
It helps to get some natural sunlight every day. This can be especially hard in the winter months when it’s dark on your drives to and from work. According to research from John Hopkins University, light itself is the driving force behind our circadian cycle. When light enters your vision, it dictates your sleep patterns by regulating and resetting the biological clock. It works by triggering your body and brain to release certain hormones and chemicals that dictate the sleep, aging and cognitive processes.
The typical American gets less than one hour a day of outdoor sunlight (4). Exercise is a great way to kill two birds with one stone. Research shows that exercising three hours before bedtime can help you fall asleep. Aim for 30 minutes a day and start slow. Exercising too close to sleep may keep you awake, so be sure to do it earlier in the day until you know how it will affect you.
Having a comfortable place to rest at night is an important part of the sleep process. Your body naturally regulates its temperature as you get sleepy, but it might also help to keep your room cool at night. The best temperature for sleeping is between 65 and 72 degrees Fahrenheit. Invest in a comfortable mattress and bed sheets to help you get cozy. Shades that block the light can be helpful to keep your room dark, especially if you’re a night shift worker and need to sleep during the day. Blocking out noise or using a white noise machine can help you drift off to sleep.
Ironically, stress is both a cause and side effect of sleep loss. Stressing over not sleeping can keep you awake. Try to stress over sleep as this can make the condition worse. Finding your natural sleep cycle may take some time. Learn to be patient with yourself. Like anything, sleeping may take practice. If you can’t fall asleep after a certain amount of time, get up and engage in a relaxing activity until you’re tired enough to try again. Remember that getting upset will make it worse.