Sleep Deprivation: The Second-Day Slump Explained

Sleep deprivation is a condition that occurs when an individual fails to get the amount of sleep required by their body. The effects of sleep deprivation can vary from person to person, but it generally impairs everyday functioning and can have serious consequences on health, mood, and overall quality of life. So, do you feel sleep deprivation more on the second day? The answer is yes. After 36 hours without sleep, an overwhelming urge to sleep kicks in, along with increased appetite and extreme fatigue. The longer one stays awake, the more severe the symptoms become, with the second day of sleep deprivation being significantly more challenging than the first.

The impact of sleep deprivation on the central nervous system

Sleep deprivation can occur after just 24 hours of no sleep. However, the longer one stays awake, the more severe the symptoms become. The impact of sleep deprivation on the central nervous system is significant.

Impact on the Central Nervous System

Sleep deprivation can impair the ability to process complex social emotions within and between the central nervous system (CNS) and peripheral nervous system (PNS). It can also disrupt the discrimination of threatening from affiliative facial cues. Sleep deprivation can further impair the peripheral, autonomic-mediated cardiac discrimination of threatening from affiliative social cues.

Sleep deprivation can also degrade the normally reciprocal associations between the central and peripheral emotion-signalling systems. This is most prominent at the level of cardiac-amygdala coupling. Moreover, REM sleep physiology across a sleep-rested night can predict the next-day success of emotional discrimination within the viscerosensory network across individuals, suggesting a role for REM sleep in affective brain recalibration.

Sleep deprivation can also impair the central brain's ability to disambiguate between varied social cues within viscerosensory cortical regions of the dorsal anterior cingulate cortex and bilateral anterior insula. This loss of neural discrimination accuracy is accompanied by a shift in behavioural responding, resulting in a biased overestimation of threats relative to a sleep-rested state, thus reducing sensitivity to prosocial, affiliative cues.

Other Effects of Sleep Deprivation

• Sleep deprivation can negatively impact the heart and circulatory systems, increasing the risk of developing high blood pressure and high cholesterol.
• It can increase the risk of developing Type 2 diabetes.
• It can negatively impact the immune system, with the body's natural defences unable to work properly.
• It can cause higher pain sensitivity, with individuals feeling pain more easily and intensely.
• It can negatively impact the brain, with severe effects on brain function, learning and memory. There is also some evidence that it could play a role in the development of Alzheimer's disease.
• It can negatively impact mental health, making it harder to manage and process emotions. Individuals are more likely to feel symptoms of depression and anxiety.
• It can cause changes in energy levels, with individuals feeling fatigued, lethargic and lacking motivation.
• It can weaken the immune system, with individuals becoming more prone to frequent colds, infections and respiratory diseases.
• It can impair brain activity, including learning, concentration and memory.
• It can negatively impact cardiovascular health, triggering harmful inflammation and raising blood pressure and blood sugar levels, increasing the risk of heart disease.
• It can cause relationship problems, with increased moodiness and anger issues, decreased sex drive and reduced production of hormones.
• It can cause changes in appearance, including premature skin ageing and weight gain.
• It can increase the risk of serious health problems, including stroke, diabetes, heart disease, Alzheimer's disease and certain cancers.
• It can add inches to the waistline, with sleep-deprived individuals craving sugary foods that provide a quick energy boost.

Recovery from Sleep Deprivation

It can take days or weeks to recover from sleep deprivation. The longer one has been awake, the longer it will take to get back on track. Recovery involves getting sufficient quality sleep.

Sleep deprivation and the immune system

Sleep deprivation is when a person doesn't get enough sleep or doesn't get good quality sleep. It can cause very disruptive symptoms that interfere with routine activities and can worsen many major health conditions. Sleep deprivation can occur after just 24 hours of no sleep, and the longer a person goes without sleep, the more severe the symptoms become.

Sleep is an active physiological process that plays a fundamental role in physical, mental, and emotional health. It exerts an immune-supportive function, promoting host defence against infection and inflammatory insults. Sleep deprivation has been associated with alterations of innate and adaptive immune parameters, leading to a chronic inflammatory state and an increased risk for infectious/inflammatory pathologies, including cardiometabolic, neoplastic, autoimmune, and neurodegenerative diseases.

Sleep deprivation may result in deregulated immune responses with increased pro-inflammatory signalling, thus contributing to an increased risk of infection and inflammation-related chronic diseases. Sleep-deprived humans are more vulnerable to respiratory infections and, compared with long sleep duration, short sleep duration is associated with an increased risk of common illnesses, including colds, flu, gastroenteritis, and other common infectious diseases.

Sleep deprivation has also been linked to a higher risk of developing certain cancers, including breast, colorectal, and prostate cancer. A reduced cytotoxic activity of natural killer cells, which are immune cells with anti-tumour effects, has been reported in sleep-deprived mice.

Additionally, sleep disturbances are frequently reported in autoimmune diseases, and immunotherapy in patients with autoimmune pathologies results in sleep improvement. Human cohort studies have found that non-apnoea sleep disorders, including insomnia, were associated with a higher risk of developing autoimmune diseases such as rheumatoid arthritis, ankylosing spondylitis, systemic lupus erythematosus, and systemic sclerosis.

In summary, impairments of the immune-inflammatory system are a plausible mechanism mediating the negative health effects of sleep deprivation, and in particular, its role in the risk and outcomes of chronic diseases such as infections, cardiovascular, metabolic, autoimmune diseases, neurodegenerative diseases, and cancer.

Sleep loss and mental health

Sleep is essential for maintaining mental health. Sleep deprivation can have a detrimental impact on mental health and can even lead to severe psychotic symptoms.

The effects of sleep deprivation on mental health include:

• Changes in energy levels, leading to fatigue, lethargy, and a lack of motivation.
• Mental health problems such as moodiness, irritability, and an increased risk of depression and anxiety. Sleep deprivation can also affect one's ability to cope with stress and manage emotions.
• Impaired brain activity, including difficulties with learning, concentration, and memory.
• Increased risk of accidents due to impaired motor skills and reaction times.
• Relationship problems due to increased anger and moodiness, decreased sex drive, and reduced hormone production.
• Changes in appearance, including premature skin ageing and weight gain.
• Increased risk of serious health problems such as stroke, diabetes, heart disease, and certain cancers.

Additionally, sleep deprivation can cause unusual behaviours, increased impulsivity, hyperactivity, and emotional outbursts. It can also lead to anger issues and make it challenging to interact with others.

Research suggests that the relationship between sleep and mental health is complex and bidirectional. Sleep problems can contribute to the development and maintenance of mental health issues, while mental health conditions can also worsen sleep problems. Addressing sleep issues early on may be crucial in preventing the development of mental health disorders.

Furthermore, sleep deprivation can affect the function of the neurotransmitter serotonin, which is linked to depression. It can also disrupt the body's stress system and circadian rhythms, increasing vulnerability to depression.

To maintain mental health, it is essential to prioritise sleep and address any sleep problems. This may involve improving sleep habits, such as limiting caffeine and alcohol intake, establishing a nightly routine, and seeking professional help if needed.

Sleep loss and physical health

Sleep is essential for your physical health. Sleep deficiency can cause you to feel very tired during the day. You may not feel refreshed and alert when you wake up. Sleep deficiency also can interfere with work, school, driving, and social functioning.

• Central nervous system: Sleep is necessary to keep your central nervous system functioning properly, but chronic insomnia can disrupt how your body usually sends and processes information. Sleep deficiency leaves your brain exhausted, so it can’t perform its duties as well. You may also find it more difficult to concentrate or learn new things. The signals your body sends may also be delayed, decreasing your coordination and increasing your risk for accidents.
• Immune system: During sleep, your immune system produces protective, infection-fighting substances like antibodies and cytokines. Sleep deprivation prevents your immune system from building up its forces. If you don’t get enough sleep, your body may not be able to fend off invaders, and it may also take you longer to recover from illness.
• Cardiovascular system: Sleep affects processes that keep your heart and blood vessels healthy, including those that affect your blood sugar, blood pressure, and inflammation levels. It also plays a vital role in your body’s ability to heal and repair the blood vessels and heart. People who don’t sleep enough are more likely to get cardiovascular disease. One analysis linked insomnia to an increased risk of heart attack and stroke.
• Hormone production: Sleep deprivation can affect the production of hormones like testosterone, growth hormone, leptin, and ghrelin.
• Weight gain: As you wake up throughout the night, this can cause sleep deprivation, which leaves you more vulnerable to respiratory infections like the common cold and flu. Sleep deprivation can also make existing respiratory diseases worse, such as chronic lung illness. Along with eating too much and not exercising, sleep deprivation is another risk factor for becoming overweight and obese. Sleep affects the levels of two hormones, leptin and ghrelin, which control feelings of hunger and fullness.

The stages of sleep deprivation

Sleep deprivation can occur after just 24 hours of no sleep, and the longer you go without sleep, the more severe and less tolerable the symptoms become. While there is no universal timeline for sleep deprivation, it is generally divided into five stages, each lasting 12-24 hours, with symptoms worsening as time awake increases.

Stage 1: After 24 hours

Missing a night of sleep will not cause major health issues, but you may feel tired, exhausted, or "off". Your risk of errors and accidents in everyday tasks may increase, and it may not be safe for you to drive.

Stage 2: After 36 hours

After 36 hours without sleep, you will have an overwhelming urge to sleep. You may experience increased appetite, extreme fatigue, and microsleeps, which are brief periods of sleep lasting around 30 seconds that occur without you realizing it. You may also start to hallucinate.

Stage 3: After 48 hours

Missing sleep for 48 hours is considered extreme sleep deprivation. It will be increasingly difficult to stay awake, and you are likely to experience more frequent microsleeps. Other possible effects include perceptual distortions, increased irritability, and temporal disorientation.

Stage 4: Awake for 72 hours

After three days of sleep loss, your urge to sleep will be very strong and possibly uncontrollable. You will likely experience longer microsleeps, and your hallucinations may become more complex.

Stage 5: Awake for 96 hours or more

After 72 hours, your perception of reality may be severely distorted, resembling acute psychosis. Your urge to sleep will be unbearable, and you may struggle to think clearly. Your symptoms will go away once you get enough sleep, but it may take days or weeks to fully recover from sleep deprivation.

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