People lead busy lives today, and it’s not easy to have enough time to maintain a balanced routine, be it either in the form of not having three meals in a day or not having a sufficient amount of sleep.
But have we ever thought of the effects of these in the long run? Does lack of sleep not cause any harm? Are insufficient sleep and hypertension correlated?
1. Navigating the World of Sleep
Sleep is essential for a regular and balanced lifestyle, and it would be wrong to say that people don’t enjoy rest. Back when life was slow, it was easier for everyone to have a good night’s sleep. Over time, getting a good rest for at least 6 hours has become a hassle. To keep up with the day-to-day pace, people tend to compromise with their sleep.
These frequent adjustments later alter the entire sleep schedule. Staying up late and sleeping the next morning only to wake up again around 8 AM or late in the afternoon is a common habit nowadays. You might think sleeping 8 hours is enough, doesn’t matter what time of the day, but it does have its effects.
Definition-wise, what is sleep?
Physiologically, sleep is a state of diminished mental and physical activity in which consciousness is modified and sensory activity is constrained to some extent. There is a reduction in muscle movement and interaction with the external environment during sleep. Sleep is different from the state of wakefulness, but some active brain patterns distinguish it from a coma and irregularities of consciousness.
Sleep occurs in repetitious periods, in which the body shifts between two definite modes: REM and non-REM sleep. REM is an abbreviation for “rapid eye movement“, but has many other attributes, including virtual paralysis of the body.
Everyone sees dreams, right? What are dreams?
Scientifically, dreams are a series of visuals, thoughts, emotions, and sentiments that typically occur involuntarily in the mind during certain stages of sleep.
The human body and most of its parts remain in an anabolic state during sleep, helping to revitalize multiple systems such as the muscular, immune, nervous, and skeletal systems. These processes are responsible for maintaining mood, memory, and cognitive function, hence, they are crucial. Likewise, they also play an important role in the operation of the endocrine and immune systems.
Humans are likely to suffer from diverse sleep disorders that include dyssomnias like insomnia, hypersomnia, narcolepsy, sleep apnea, parasomnia such as sleepwalking, rapid eye movement during sleep, and bruxism. One of the most significant reasons for an increase in sleep disorders is the growing use of artificial light. The sources can be outdoor lighting or light emitted from electronic gadgets. These devices emit blue light which typically denotes the daytime, further disrupting the release of melatonin, a hormone that regulates the sleep cycle.
2. The Physiology Behind Sleep
The most prominent and notable physiological changes in sleep occur in the brain. Isn’t that crazy? When you are in your most inactive state after a whole day of working, that’s when changes occur in the brain. However, the brain uses up less energy in sleep than in an awakened state, particularly during non-REM sleep.
Wherever the activity is minimized, the brain replenishes its reserve of adenosine triphosphate (ATP), the molecule used for momentary storage and distribution of energy. When waking up quietly, the brain is in control of 20% of the body’s energy utilization, thus this lowering has an evident effect on overall energy consumption.
Sleep increases one’s sensory threshold. To put it in simpler words, although the body is resting during sleep, and you can sense fewer stimuli, typically you will be able to respond to loud noises and other focal sensory episodes. During slow-wave sleep, better known as deep sleep, humans secrete a load of growth hormones. All kinds of sleep, even sleeping in the day is concerned with the release of a hormone called prolactin.
2.1. Brain Waves During Sleep
An electroencephalograph, abbreviated as EEG displays the electrical activity of the brain in the form of waves. The different amplitudes of an EEG wave at a particular frequency denote several stages of the sleep-wake cycle, such as falling asleep, being asleep, or being awake. The different waves, namely, alpha, beta, gamma, delta, and theta waves are all seen in different stages of a sleep cycle. Each waveform has a distinct amplitude and frequency.
Each of the waves that are seen in an EEG waveform denotes a different stage. The alpha wave is when the person is resting but is in a conscious state, where the eyes might be closed and the body is still and is beginning to slow down.
The beta waves overtake the alpha waves when a person is attentive, as they might be completing a task or concentrating on some work. The amplitude of a beta wave is the lowest, however, the frequency is the highest.
The gamma waves are visible when a person uses their full concentration to focus on a task. When the person is awake, theta waves occur and transit into stages 1 and 2 of sleep. Delta waves occur in stages 3 and 4 of sleep when a person is in their deepest sleep.
2.2. REM and non-REM Sleep
The two broad categories of sleep are REM, which is rapid eye movement, and non-REM, which is non-rapid eye movement sleep. How different are these two? Enough differences for physiologists to identify them as two distinctive behavioral states. The first to occur is the non-REM sleep which transitions from a phase called deep sleep or slow-wave sleep. The body temperature and heart rate fall during this stage and the brain consumes less energy.
On the other hand, REM sleep, also called paradoxical sleep, denotes a smaller portion of the sleep cycle and is typically the prime occasion for dreams, and nightmares, and is linked with brain waves that are rapid and not synchronous, eye movements, loss of muscle tone, and suspension of homeostasis.
The average time taken between the alteration of n-REM and REM is 90 minutes, happening at least 4-6 times in a good night’s sleep. As per the American Academy of Sleep Medicine, non-REM sleep is divided into three stages, n1, n2, and n3, the last being called slow-wave sleep or delta sleep. The whole process proceeds in the order: n1 to n2, n2 to n3, n3 back to n2, and in the end, n2 to REM.
When the person returns to stage 1 or 2 of sleep, REM occurs, and a greater amount of deep sleep, or n3 occurs earlier in the night, and the distribution of REM increases in the two cycles just before a person naturally wakes up from sleep.
3. Sleep Disorders
Plenty of people around the world suffer from sleep disorders, nowadays. The general term for defining the difficulty of falling asleep or staying asleep is insomnia. It is also the most common sleep problem that is widely spread across the globe. Most people report cases of occasional insomnia, while 10-15% of the population suffers from chronic insomnia.
Several underlying reasons might lead to insomnia including psychological, physical, or emotional. Causes such as psychological stress, poor sleep environment, fluctuating sleep schedule, and exaggerated physical or mental stimulation before going to bed, are more likely to affect the overall sleep cycle.
The treatment of insomnia is usually done via behavioral alterations such as keeping a regular sleep routine, refraining from doing stressful activities just hours before nap time and cutting down on substances such as caffeine. The environment where one sleeps can be modified by heavily draping it to block out sunlight and keeping computers, televisions, and other electronic devices away from the sleeping room.
Sleeping medications, which include, Nonbenzodiazepines such as Ambiane, Imovane, and Lunesta were earlier believed to be better, safer, and more effective than earlier generations of sedatives, however, they are now same as benzodiazepines in terms of their biochemical and physiologic effects, just differ at the molecular level in their chemical structure.
4. How Important is Sleep Health?
What if your sleep health is not up to the mark? You might wonder, how worse could it be? Is insomnia all that you might develop? That can be treated with proper medications and precautions, right? Insomnia is a very commonly occurring sleep disorder, affecting a significant portion of the population, however, poor sleep health might not just lead to insomnia but maybe something worse.
Irregular sleep cycles have been associated with a variety of medical complications including cardiovascular disorders, mental illness, and obesity. Poor sleep is common in people with preexisting cardiovascular diseases, however, studies show that it can be a contributing cause.
Sleeping for a short duration like less than 6-7 hours can be correlated with coronary heart disease and increased deaths due to it. Sleep duration of more than 9 hours is linked to coronary heart disease, as well as stroke and cardiovascular episodes.
In children and adults, a short period of sleep is related to an elevated risk of obesity, with multiple research reporting a 45-55% increase in risk. Some other attributes of sleep such as daytime napping, sleep timing, the variability of sleep timing, and low sleep efficiency have been correlated with obesity, out of which sleep duration is being studied most for its impact on obesity.
5. Blood Pressure 101
The blood pressure of a normal resting person is around 120 mmHg over 80 mmHg. Sounds familiar? This is a statement that the majority of you have heard at some point in your life, typically during a visit to the doctor. What is blood pressure? In medical terms, blood pressure is the pressure of circulating blood exerted against the walls of the blood vessels. Most of the contribution results from the heart pumping the blood through the circulatory system.
For amateurs, the term ‘blood pressure’ refers to the pressure in the brachial artery, where it is usually measured. The pressure is expressed in terms of the systolic pressure, which is the maximum pressure during one heartbeat, over the diastolic pressure, which is the minimum pressure between two heartbeats. It is measured in millimeters of Mercury which is mmHg.
Along with respiratory rate, heart rate, oxygen saturation, and body temperature, blood pressure is one of the vital aspects that medical professionals use to evaluate an individual’s overall health. As mentioned previously, the normal resting blood pressure for an adult is 120 mmHg systolic over 80 mmHg diastolic.
6. Navigating the Highs and Lows
Medical conditions that involve unusual levels of blood pressure within the circulatory system, come under blood pressure disorders. There are mainly two types of blood pressure disorders, high blood pressure or hypertension and low blood pressure or hypotension.
Hypertension or high blood pressure is a chronic medical condition that causes a persistent elevation in blood pressure. There are no symptoms to characterize high blood pressure, however, it is a major risk factor for stroke, heart failure, vision loss, and chronic kidney disease.
On the other hand, hypotension or low blood pressure is a type of blood pressure disorder characterized by systolic pressure lower than 90 mmHg and diastolic pressure lower than 60 mmHg. If the symptoms are significant the blood pressure is considered to be too low. Let us have a broader perspective of both these disorders.
7. Beneath the Surface: Hypotension
Simply put, hypotension is a medical condition characterized by a drop in both systolic and diastolic pressure lower than 90 mmHg and 60 mmHg respectively. When the symptoms become prominent. The pressure is deemed to be very low.
The common symptoms of having low blood pressure are dizziness, lightheadedness, exhaustion, fatigue, and fainting. Too much lowered blood pressure can deprive the brain and other essential organs of oxygen and nutrients in the body, leading to a severe condition called shock.
The causes of hypotension can be excessive heat, low blood volume, hormonal alterations, anemia, vitamin B12 deficiency, heart problems, or endocrine problems. Some medications can also lead to hypotension. Excessively low blood pressure can lead to dizziness and fainting or indicate serious heart, neurological, and endocrine disorders.
8. Rising Tides: Hypertension
A prolonged medical complication characterized by a consistent increase in blood pressure in the arteries is known as high blood pressure or simply hypertension. There aren’t any significant symptoms that can help identify this disorder, but it is a leading risk factor for cardiac diseases, stroke, kidney diseases, and dementia.
Hypertension is then classified into two categories, primary hypertension and secondary hypertension. 90-95% of cases of hypertension come under primary, caused due to non-specific lifestyles and genetic disorders. Excess salt in diet, smoking, too much body weight, alcohol use, and physical inactivity are certain lifestyle factors that lead to hypertension. The rest 5-10% of cases come under secondary hypertension.
If the resting blood pressure is consistently at or above 130/80 mmHg or 140/90 mmHg, it is a case of hypertension. Hypertension is more prevalent in people with diabetes as compared to non-diabetic people. This disorder can be treated using medications and changes in lifestyles, such as weight loss, physical exercise, less salt consumption, reducing alcohol intake, and maintaining a healthy diet.
9. Insufficient Sleep and Hypertension
Irregularities in the sleep cycle as well as the blood pressure can cause complications in the long run. But how can we correlate these two distinct conditions? How can we relate insufficient sleep and hypertension?
Adults are recommended to get 7-8 hours of sleep every night. Sleeping for less than 6 hours is considered to be bad for overall well-being. You are high at risk of developing cardiac disorders due to disturbances in your sleep patterns, which can be caused by stress, jetlag, or some other factor.
It has been found that regular lack of sleep can lead to hypertension in children and grown-ups. The less you sleep, the higher your blood pressure can rise. People with existing high blood pressure are more susceptible to increased hypertension if they sleep less every day.
The idea is based on the thought that the body rests when you are asleep and thus controls hormones that are needed to regulate metabolism and stress. Over time, as you make a habit of sleeping less, the hormone balance is disturbed hence leading to an increased blood pressure.
Additionally, it is not advisable to fill up that gap by sleeping more, as too much sleep can lead to high blood sugar and weight gain, which further results in cardiovascular problems. Obstructive sleep apnea is a sleep disorder that causes high blood pressure or hypertension. This disorder causes breathing to suddenly stop and start during sleep.