Process S represents the drive for sleep, increasing during wakefulness and decreasing during sleep, until a defined threshold level, while Process C is the oscillator responsible for these levels. When being sleep deprived, homeostatic pressure accumulates to the point that waking functions will be degraded even at the highest circadian drive for wakefulness. Microsleeps
Microsleeps are periods of brief sleep that most frequently occur when a person has a significant level of sleep deprivation. Microsleeps usually last for a few seconds, usually no longer than 15 seconds, and happen most frequently when a person is trying to stay awake when they are feeling sleepy. The person usually falls into microsleep while doing a monotonous task like driving, reading a book, or staring at a computer. Microsleeps are similar to blackouts and a person experiencing them is not consciously aware that they are occurring. An even lighter type of sleep has been seen in rats that have been kept awake for long periods of time. In a process known as local sleep, specific localized brain regions went into periods of short (~80 ms) but frequent (~40/min) NREM-like states. Despite the on and off periods where neurons shut off, the rats appeared to be awake, although they performed poorly at tests. Cardiovascular morbidity
Decreased sleep duration is associated with many adverse cardiovascular consequences. The American Heart Association has stated that sleep restriction is a risk factor for adverse cardiometabolic profiles and outcomes.
Sleep state misperception is diagnosed when people get enough sleep but inaccurately perceive that their sleep is insufficient.Secondary insomnia, or comorbid insomnia, occurs concurrently with other medical, neurological, psychological and psychiatric conditions. Causation is not necessarily implied.Sleep is known to be cumulative. This means that the fatigue and sleep one lost as a result, for example, staying awake all night, would be carried over to the following day. Not getting enough sleep a couple days cumulatively builds up a deficiency and thats when all the symptoms of sleep deprivation come in. A well rested and healthy individual will generally spend less time in the REM stage of sleep. Studies have shown an inverse relationship between time spent in the REM stage of sleep and subsequent wakefulness during waking hours. Sleep apnea
Sleep apnea is a serious disorder that has symptoms of both insomnia and sleep deprivation, among other symptoms like excessive daytime sleepiness, abrupt awakenings, difficulty concentrating, etc. Obstructive sleep apnea is often caused by collapse of the upper airway during sleep, which reduces airflow to the lungs. Those with sleep apnea may experience symptoms such as awakening gasping or choking, restless sleep, morning headaches, morning confusion or irritability and restlessness. This disorder affects between 1 and 10 percent of Americans. It has many serious health outcomes if untreated. Positive airway pressure therapy using a CPAP (Continuous positive airway pressure), APAP or BPAP devices is considered to be the first line treatment option for sleep apnea.