This means that caffeine mainly works by occupying adenosine receptors in the brain, specifically, receptors that influence sleep, arousal, and cognition. Once it is in the body, caffeine will persist for several hours, and takes about six hours for one half of the caffeine consumed to be eliminated. When caffeine reaches the brain, it increases the secretion of norepinephrine which is related to the "fight or flight" response. The rise in norepinephrine levels increases activity of neurons in areas of the brain and the symptoms resemble those of a panic attack.The half-life of caffeine is roughly 3–4 hours in healthy adults, however, it is dependent on a variety of variables such as age, liver function, medications, level of enzymes, pregnancy. This short half-life has been found to help out daytime functioning, but increase the side effect of sleep problems. So, while caffeine has the potential to increase performance, it comes at a cost of sleep deprivation which in its own way can counter the main point of caffeine. Sleep deprivation alone can cause a variety of problems associated with cognitive control and functions. This can include reduced alertness, attention, vigilance, speed of motor functions.Though caffeine can be shown to decrease the quality of sleep, there is no evidence that caffeine affects all people the same way. In fact, some people report no sleep problems despite regularly consuming caffeine. Regular intake of caffeine may be normal for a person so it is understandable how they may still get satisfactory sleep.
Even though the suggested amounts of sleep is relatively well known, there are increasing high numbers in the lack of healthy and good quality sleep.Risk factors of sleep can range across many different arrays such as environmental, lifestyle, psychosocial, sleep disorders, or medical conditions. These are all circumstances which put individuals at risk for sleep disruption. Environmental risk factors for sleep disruption can include living in an area where there is excessive noise such as near an interstate, keeping an individual up later than normal. A lifestyle risk factor would include drinking alcohol, drug abuse, or a late shift at work. Psychosocial risk factors include being a caregiver for someone who needs constant attention, parents of young children, anxiety, worry, or stress, etc.Sleep plays an essential part in brain functions and has crucial implications across almost all body systems. Numerous studies have shown caffeine consumption to heavily disrupt sleep patterns. This can lead to other implications such as lengthening the onset of sleep latency and decrease the efficiency and duration of sleep. Disruption of sleep also affects pressure for sleep and lowers electroencephalogram power in the frontal, central, and parietal regions of the brain. Short-term consequences of sleep disruption include: an increase in stress, emotional distress, mood and other mental health problems, cognition, memory, and performance deficits as well as an increase in behavioral problems in normally heathy individuals.