Sleep Cycle

1. What Is the Body’s Natural Sleep Cycle?

When you fall asleep, you experience sleep in cycles. One sleep cycle in an individual is made up of non-rapid eye movement (NREM) and rapid eye movement (REM) sleep periods. Sleep cycles are repeated throughout your sleep time until you wake up. Generally, up to five full sleep cycles take place before you wake up.

2. What Are the Sleep Cycle Stages?

Your sleep cycle goes through four stages of NREM and REM sleep many times during a typical night. As we progress toward the morning, the REM periods become more profound and more prolonged. Following are the stages of a regular sleep cycle.

2.1. Stage 1 NREM:

The stage 1 NREM period is the switch that turns off wakefulness and turns on sleep. It is a short period that is characterized by light sleep. During the stage 1 NREM period, your eye movements, heartbeats, and breathing slow down, and your muscles relax. The brain waves become slower as compared to the wakefulness wave pattern during the daytime. Occasionally, muscles might have extremely minute twitching.

2.2. Stage 2 NREM:

This stage of NREM is a period of light sleep before you enter a deeper sleep phase. Your muscles, breathing and heartbeat patterns relax even further. Your eye movements stop and the body temperature drops. The brain has some brief bursts of electrical activity, and the wave activity slows down. You spend more time in stage 2 of sleep than in any other stage of your repeated sleep cycles.

2.3. Stage 3 and Stage 4 NREM:

Stages 3 and 4 of NREM sleep are the periods in which you enter deep sleep, the sleep that makes you feel refreshed in the morning. These stages have a longer duration in the first half of the night. Your muscles relax, your breathing becomes slow and rhythmic, and your heartbeats slow down to their lowest levels during these stages of sleep. Brain activity lowers even further than in stage 2. It becomes difficult to wake you up when you enter stages 3 and 4 of sleep.

2.4. REM:

REM sleep occurs for the first time in about 90 minutes after you fall asleep. Behind your closed eyelids, your eyes move rapidly from side to side. Your brain wave activity has a mixed frequency similar to the brain wave activity seen in wakefulness. Your blood pressure and heart rate increase to near waking levels and breathing becomes irregular and fast. Most of the dreams that you see occur in this phase, though some dreams can also occur in NREM sleep. You are not able to act out your dreams because your arm and leg muscles become temporarily paralyzed. As you grow old, your sleep duration in the REM stage decreases. Consolidating of memories while you are asleep most likely requires REM as well as NREM sleep.

3. How Long Is a Sleep Cycle?

Humans experience up to five such sleep cycles in a full night’s sleep, each lasting for about 90 to 100 minutes.

Healthy sleep is distributed in five stage cycles. Stage 1 or drowsy sleep happens when you transition between waking and sleeping. This stage lasts a few minutes. Stage 2 accounts for 50% of your sleeping time. Once stages 1 and 2 are over, you reach stage 3 and 4 of deep sleep or slow wave sleep and then, REM stage. In a typical night, NREM and REM occur in cycles; each stage lasts for up to 15 minutes.

As the night proceeds, the later sleep cycles have less of slow wave sleep and more of REM sleep.

People under the age of 30 have approximately two hours of restorative sleep every night while people aged over 65 years may get only 30 minutes of restorative sleep.

4. How Does Sleep Deficit Affect Your Work Performance?

Sleep experts like The American Academy of Sleep Medicine (AASM) and Sleep Research Society (SRS), say that most adults need at least seven to nine hours of sleep every day. According to the “Sleep in America” poll, 2018, from the National Sleep Foundation, 65% of American adults say that getting enough sleep improves their effectiveness. However, responsibilities and commitments at work, family obligations, and evening activities all affect the time at which executives sleep and wake up.

The REM stage gets affected the maximum when you have not had an adequate sleep. Of the 4-5 sleep cycles that you experience during sleep, the later sleep cycles have longer REM sleep duration. Those who sleep for less time do not experience the longer REM sleep duration. Inadequate REM sleep affects the brain instantly. It becomes hard for the brain to focus on a single activity in the office. Thus, it affects multitasking, an inescapable requirement in a manager’s job.

Shortage of REM sleep will also make it hard for you to pick up nuances in negotiations or discussions. This can be particularly detrimental to CEOs and high-level executives who are decision makers.

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5. How Does Sleep Deficit Affect your Health?

Although top-ranking executives set exacting schedules for themselves at the cost of sleep and pride themselves on being able to function optimally with just 5-6 hours of snooze time, in reality, they are simply shortchanging their companies and themselves.

Thus, research shows that poor quality of sleep or a constant lack of sleep increases the risk of disorders such as:

– Heart diseases

– Diabetes

– Obesity

– High blood pressure

– Depression

Enough sleep is necessary, but quality sleep is all the more critical. Consult your doctor if you find the following patterns in your sleep:

– Feeling tired or sleepy even after sleeping enough

– Frequently waking up during the night

– Having symptoms of sleep disorders like gasping for air or snoring

6. How Does Jet Lag Affect Your Sleep Cycle?

Jet lag is one of the most common sleep disorders among millions of travelers, especially executives and entrepreneurs, as a consequence of crossing multiple time zones. Studies have shown that jet lag results in an imbalance between the body’s natural biological/circadian clock and the new time zone, which affects our sleep cycle. Thus, when we arrive at a new time zone, our bodies don’t immediately catch up with that city’s timings and take time to adjust. They tend to stay in their original biological schedule for many days.

A well-known sign of jet lag is a decline in sleep quality occurring in 60% to 70% people on the first night after crossing a time zone and only in 30% of the people on the third night. You may also notice symptoms like dyspepsia (infection or inflammation in the digestive tract) or constipation (probably due to the change in meal times), disorientation, depression and a reduced ability to estimate the distance, space, and time. Executives who are frequent travelers and have frequent sleep disturbances can develop irritability, impaired performance in tasks that require attention, and malaise (feeling discomfort and ill without an exact reason). Businesswomen who are jet lagged frequently tend to have irregular menstrual cycles.

The rhythm of the circadian clock follows the rise and fall of plasma levels of some hormones, body temperature, and other biological settings, according to Biology. Hormones like thyroid, growth hormone, cortisol, and prolactin; nutrient-sensitive hormones like leptin, insulin, and ghrelin also get affected due to a change in the circadian clock.

Following is a list of some tips to help reduce the effects of jet lag on your sleep:

1. Go to bed and wake up a couple of hours earlier before an eastward trip and a couple of hours later for a westward trip for a few days. It will help your body anticipate and match the time change in the new time zone.

2. Change the time in your watch according to the time zone of your destination once you board the plane.

3. Avoid caffeine and alcohol at least 3 to 4 hours before bedtime. These substances act as stimulants and do not let you sleep.

4. Carry blindfolds and earplugs to reduce unwanted lights and sounds while you sleep.

5. Step outside in the sun whenever possible. Daylight is a powerful stimulant to adjust the biological clock. Jet lag worsens if you stay indoors.

6. Avoid any type of heavy exercise before bedtime. Light exercises earlier in the day are good.

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7. How Do Smoking, Alcohol, and Caffeine Affect Your Sleep?

Sleep disturbances are common among cigarette smokers as the nicotine acts as a stimulant and keeps them awake, according to studies. Smoking is associated with difficulty in sleeping and waking up. Male smokers have nightmares and disturbing dreams while female smokers feel excessively sleepy during the day.

Alcohol in lower doses may have sedative effects, but studies show that high alcohol doses in healthy people cause sleep disturbances. In addition to creating problems in sleep initiation and disturbances in sleep, researchers have discovered that alcohol consistently affects the proportion of various sleep stages in the sleep cycle.

Caffeine acts as a stimulant; it improves alertness, causes insomnia, headaches, dizziness, and nervousness. Several studies have shown that caffeine blocks the action of sleep-inducing chemicals in the brain, for example, melatonin (a hormone that makes you feel drowsy) and adenosine (a hormone that reduces the activity of your neurons) and increases adrenaline production.

8. How to Reset Your Sleep Cycle?

Your sleeping pattern depends on your circadian rhythm, the inbuilt physiological clock that regulates alertness, body functions, and sleepiness.

There are two primary reasons executives continue to have sleep disturbances despite their best efforts to get a good night’s sleep: stress and jet lag. These issues can be tackled to reset your sleep cycle in the following ways:

8.1. Executives Who Have a Disturbed Sleep Pattern Because of Stress

The line-up of meetings and deadlines is always a stress additive aspect in executives. A research study published in the Behavioral Sleep Medicine has proven that mental stress can have an adverse impact on the quality of sleep and affect the body’s circadian rhythm.

In that case, there is no one-size-fits-for-all sleeping pattern for everyone. Individual variations come up while considering the best hours to sleep. Some adults are owls (night lovers), some are larks (morning lovers), and some are between these two.

The best way to get a healthy sleep cycle is to match your body rhythm with your sleeping pattern to get your regular seven- to nine‑hour sleep. Set a bedtime slot and a pre-determined wake-up time in your mind, for example, a time between 8:00 PM and 12:00 PM; then make slight variations in your sleep and wake up timing to see what works the best for you. If you get up an hour early before the set time in your alarm, try pushing ahead your bedtime to a bit later. If you cannot fall asleep at night and you’ve been trying to fall asleep for more than 20 minutes, it may be too early for you. If you find it a struggle remaining awake till your set bedtime, try moving the bedtime to a little earlier.

Once you have found the optimal bedtime slot for you, follow it consistently throughout the week. This will set your body’s internal clock accordingly. Once you reset your internal clock, it will be easier for you to fall asleep and stay asleep, thus improving your function.

Following are some extra tips that executives can follow to reset their sleep cycle:

1. Avoid stimulating substances like chocolate, nicotine or coffee before going to bed.

2. Keep the clock away from you at night as it can make you more stressed if you are unable to sleep.

3. Turn off your electronic devices before bedtime.

4. Ensure that your bedroom is quiet, cool, and dark. Try using white noise (even a fan could work!) to cancel out other background sounds. Choose comfortable pillows and mattress.

5. Exercise regularly, mainly during the mornings and afternoons.

8.2. Executives Who Are Frequent Travelers and Experience Jet Lag

Business professionals need to travel around the globe quite often. These travels could last from several hours to a few days. Jet lag is a major concern while traveling across different time zones, since it can disrupt your body’s circadian rhythm and affect your sleep cycle. It can certainly take a toll on the quality of our sleep. A cure for jet lag is yet to be found. However, health professional and travel experts have discovered techniques to minimize jet lag effects, which will help in resetting the sleep cycle as well:

1. Change your meal and bed schedules a few days before your trip. Move your mealtimes and bedtimes to earlier if traveling eastward and move them to a little later if you’re traveling westward.

2. Do not sleep until it is bedtime in the new time zone.

3. Follow the sun as your wake-up clock. It will help you readjust your sleep schedule.

4. Stay hydrated during your journey. Have plenty of water and avoid consuming alcohol or caffeine as they make you dehydrated and worsen your jet lag.

5. Take melatonin pills. Melatonin is a hormone that our body releases naturally as the sun goes down. You can take over-the-counter melatonin supplementation pills to help reduce the inability to sleep or disturbances in sleep.

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A study conducted among people who took long-haul flights showed that those who took melatonin supplements experienced less jet lag symptoms and tiredness. It was easier for them to get back on the sleep schedule as compared to those who didn’t take melatonin supplements.