Some people need to sleep more, and others can get away with less sleep. What really matters is that everybody needs to get enough sleep to stay healthy! Not getting enough rest is equally detrimental to health as not having enough oxygen in the blood or not enough food and water in the body.
Short sleep duration is common among U.S. adults – about 1 out of every 3 Americans is sleep-deprived. Poor slumber is linked to lower sex drive, weakened immune system, memory issues, weight gain, risk of certain cancers, diabetes, and the likelihood of accidents.
We are all familiar with that awful feeling of being tired, cranky, and out of sorts throughout the day. In the past, sleep deprivation was used as a torture method. It turned out to be quite effective because people don’t tolerate sleep restriction well.
Sleep is equally important for the body as it is for the mind. Above all, sleep significantly impacts physiological processes like digestion, immune system, libidos, and hormone levels.
How much sleep do we need?
The answer to this is very specific to the individual, so we will break it down for you. On average, adults need approximately 7-9 hours each day; some individuals only require 4 hours of shut-eye. Based on research studies, the factors that affect how many hours of sleep you need for optimal health are:
- Physical Activity
Sleep quantity and quality can contribute to an increase in weight and obesity as well as your mood, work, and energy.
Negative Effects of Sleep Deprivation
Here are four consequences of insufficient sleep,
1. Weight Gain
Lack of sleep and exercise do not mix well together, as you probably know. Obviously, It’s less likely for a sleep-deprived person to exercise or workout. For those who don’t get enough sleep, leptin levels decrease while ghrelin levels increase. In other words, the body sends a clear message to the brain: “I feel an urge to eat, and I’m not full at all!” That’s the chemical background of an overeating session. Many epidemiological studies showed a clear connection between sleep reduction and obesity among children, adolescents, and adults.
The research team at Clinical Sciences Research Institute (from the University of Warwick Medical School, Coventry, UK) published a cross-sectional study in 2008 to assess if the evidence supports the relationship between sleep deprivation and obesity among children and adults.
The total number of adult participants in the study: 604,509. The conclusion is clear: there is a strong connection linking obesity and not getting enough sleep in adults. 
2. Mental Status
When you don’t get enough sleep, your mental status completely changes. The lack of sleep “slows down“ the learning process and affects short-term memory. This creates mood swings, nervousness, anxiety and can cause severe psychological damage.
Long-term effects are even more frightening. Sleep deprivation worsens the symptoms, or in some people, triggers unpleasant feelings. The worst of these symptoms are depression, impulsive behavior, paranoid behavior, hallucinations, and even suicidal thoughts.
Some people experience sudden sleep episodes which they are not aware of. An episode may last anywhere from a few seconds up to a few minutes and can happen anywhere, even while driving.
3. Immune System
Sleep is a strong regulator of immunological processes. Many of the immune system functions have a characteristic rhythm that relies on a sleep-wake cycle. The study published in 2011 suggests that fast-acting immune cells peak in numbers during the wake of the cycle, optimizing the body’s defense and reparational mechanisms.
Injuries and infections (due to an injury) are more likely to happen during the wake cycle; therefore, the body mobilizes its forces at that time. During the sleep cycle, processes related to forming and preserving long-lasting immunological memory became predominant activity. 
A prolonged lack of sleep triggers stress response which is called a complex hormonal cascade. Consequently, this initiates the production of pro-inflammatory substances that have detrimental effects on health (low-grade inflammation and immunodeficiency).
4. Endocrine System
In 2005, a team of researchers from The Pulmonary Center of the Boston University School of Medicine published research about the connection between sleep duration, diabetes, and impaired glucose tolerance. As a result, it turned out that a sleep duration of 6 hours or less corresponds to an increased risk of diabetes and impaired glucose tolerance (a step to diabetes). 
Another study published in 2010 revealed that short sleep duration is a risk factor for hypercholesterolemia . Increased cholesterol is one of the leading risk factors for stroke and heart attack.
The list of studies about the impact of sleep duration on metabolic health grows day by day, and based on the data gathered so far, we know that prolonged sleep restriction does the following:
– Triggers a secretion of stress hormones
– Increases risk of cardiovascular disease
– Increases the risk of metabolic syndrome and diabetes
– Worsens hypertension
– Reduces insulin sensitivity
– Has a negative effect on cardiovascular health
Stages of Sleep
People normally pass through five stages of sleep:
- Stage 1 (2-5%) – The “light sleep” stage. It consists of drifting in and out of sleep and can easily be interrupted.
- Stage 2 (45-55%) – More intense “light sleep” stage. An uninterrupted form of stage 1 that result in eye movement stops with slower brain waves.
- Stage 3 (3-8%) – The “deep sleep” stage. In stage 3, extremely slow brain waves (delta waves) are difficult to interrupt.
- Stage 4 (10-15%) – More intense “deep sleep” stage. The brain exclusively produces delta waves and cannot easily be interrupted.
- REM – “restful sleep” stage. In REM sleep, or Rapid Eye Movement (REM) sleep, brain activity increases while the eyes remain closed but move rapidly from side-to-side and suppressed muscle activity.
Natural Ways to Sleep Better
Make your bedroom sleeping environment as optimized as you can, such as mattress, lighting, etc. One of the most natural ways to relax is scents. Here are the best scents that can help relaxation and promote sleep:
- Lemon or Yuzu
- Ylang Ylang
- Clary sage
According to a study by the Journal of Pineal Research, sleeping in a room that is insufficiently dark with televisions, computers, or iPads can prevent the metabolism from working at its best during sleep. The light emitted from these device screens or even street light passing through blinds works by disturbing melatonin production in the body, which leads to a reduced efficiency regarding how the body itself processes food. Melatonin is naturally present in plants, animals, and humans. It works as a hormonal signal released during the night to establish circadian rhythms.
 Cappuccio, F. P., Taggart, F. M., Kandala, N.-B., Currie, A., Peile, E., Stranges, S., & Miller, M. A. (2008). Meta-Analysis of Short Sleep Duration and Obesity in Children and Adults. Sleep, 31(5), 619–626.
 Besedovsky, L., Lange, T., & Born, J. (2012). Sleep and immune function. Pflugers Archiv, 463(1), 121–137. http://doi.org/10.1007/s00424-011-1044-0
 Daniel J. Gottlieb, Naresh M. Punjabi, Ann B. Newman, Helaine E. Resnick, Susan Redline, Carol M. Baldwin, F. Javier Nieto. Association of Sleep Time With Diabetes Mellitus and Impaired Glucose Tolerance. Arch Intern Med. 2005;165(8):863–867. doi:10.1001/archinte.165.8.863
 Gangwisch, J. E., Malaspina, D., Babiss, L. A., Opler, M. G., Posner, K., Shen, S., … Ginsberg, H. N. (2010). Short Sleep Duration as a Risk Factor for Hypercholesterolemia: Analyses of the National Longitudinal Study of Adolescent Health. Sleep, 33(7), 956–961.