Sleeping well is a vital component of a healthy an active lifestyle. While the functions of sleep are only partially understood, the negative and positive consequences of sleep loss are substantially supported in scientific literature. This article outlines the physiological effects of a lack of deep sleep, including physical symptoms, such as cognitive and physical impairment, and progressive illnesses such as diabetes.
Sleep cycles are defined by the American Academy of Sleep Medicine in two broad types: rapid eye movement, and non-rapid eye movement stages. The stages each exhibit unique physiological, psychological and neurological features and implications.
The non-rapid eye movement stage is further categorised into three subcategories:
- N1, which is the first transition from waking to sleep where the subject loses some muscle tone and awareness of the surrounding environment,
- N2, when awareness of the environment disappears, and
- N3, which is the deepest stage of NREM sleep.
During this stage, most people experience the phenomenon of dreaming. It usually lasts about 25% of total sleep time.
What is sleep deprivation?
Simply, sleep deprivation occurs when a subject does not get enough of each stage of sleep. Difficulty achieving REM sleep, or significant amounts of NREM sleep can also produce sleep deprivation.
Lack of sleep can result in achy muscles, hand tremors, headaches, and increases risk of stress, high blood pressure, diabetes, fibromyalgia, obesity and yawning.
Getting to sleep and sleeping better can have dramatic improvements on cognitive function. Sleep deprivation can result in memory loss, depression, hallucinations, irritability, psychosis, attention deficit hyperactivity disorder, and temper tantrums in children.
Gottlieb DJ, Punjabi NM, Newman AB, et al. published a study in April of 2005 which showed that participants in their sample who slept fewer hours had higher instances of diabetes. This study, however, was only correlational and the direct cause and effect relationship is still unknown.
Prolonged sleep deprivation has been shown to increase food intake and imbalance hormones leading to weight gain. It has been suggested that the obesity problem in the United States is at least partially linked to the fewer hours Americans spend sleeping.
Uses of sleep deprivation
Recent studies have shown that about 60% of patients treated with sleep deprivation for depression show immediate recovery, but with a high rate of relapse.
Sleep deprivation has historically been used as a means of interrogation. The truthfulness of information obtained through deprivation is hotly debated in the scientific community, as some argue it renders the subject cognitively impaired so any information gathered by this means is unreliable.