Types of Insomnia
Transient insomnia, lasting a few days to a week, can be triggered by many things (e.g., excess environmental noise, medications, and extreme temperatures). One type of transient insomnia is jet lag, in which traveling through time zones causes a temporary disruption of the body's circadian rhythm (NHLBI 1995).
Acute insomnia may last for several weeks. Common triggers include emotional stress or conflict, environmental changes, or anxiety associated with going to bed. Acute insomnia can also be triggered by the same things that trigger transient insomnia (American Academy of Sleep Medicine 2001; Ellis 2012).
Chronic insomnia, which may last for months or years, can have profound effects on health, quality of life, productivity, and safety (Roth 2003).
Insomnia Increases Disease Risk and Exacerbates Existing Conditions
Insomnia can lead to elevated levels of cortisol, epinephrine and other "stress" hormones (Bonnet 2010; Zhang 2011). Elevated levels of cortisol can cause weight gain, weaken the immune system, and increase risk of developing diabetes and osteoporosis (Chiodini 2008; Butcher 2005; Duong 2012).
In addition, insomnia triggers the release of chemicals (e.g., interleukin-6 [IL-6] and tumor necrosis factor-alpha [TNF–α]) that promote inflammation, which is associated with arthritis, inflammatory bowel disease, heart disease, and other conditions (Irwin 2006).
Insomnia can exacerbate chronic pain conditions by causing heightened sensitivity to pain and interfering with the body's ability to modulate central pain signals (Smith 2009). As a result, poor sleep can increase the amount of pain perceived by people with chronic pain disorders (e.g., osteoarthritis and fibromyalgia). Therefore, treating insomnia may help reduce pain in individuals with chronic pain disorders.
A study reported that among healthy individuals, average sleep duration of six hours or less per night was associated with a four-fold increased riskof stroke compared to sleep duration of 7 – 8 hours (UAB News 2012).