Health and productivity effects of poor sleep

Obvious symptoms of sleep deprivation constant yawning and the tendency to doze off when not active for a while; for example, when watching television, Grogginess when waking in the morning Sleepy grogginess experienced all day long (sleep inertia) Poor concentration and mood changes (more irritable).

Disease

Some of the physical effects found from long term fatigue are heart disease, diabetes, high blood pressure, gastrointestinal disorders and depression (Workplace health and safety QLD, 2008).  A study conducted by Andersen involving rats also showed sleep deprivation affects the expression of genes related to metabolic processes, response to stimulus and signalling pathways (Andersen et al, 2009). 

Numerous studies have shown that even a little bit of sleep deprivation decreases efficiency and increases risk of disease, including cardiovascular disease, cancer and diabetes.  Sleep deprivation has been shown to negatively affect endocrine (hormones) and metabolic functioning as well as nervous system balance (Nilsson, et al., 2004).  Sleep deprivation is associated with an increased concentration of cortisol plus other indicators of increased stress such as elevations in pulse rate, body temperature and adrenaline secretion (Vgontzas, et al.,1999).  Sleep deprivation also appears to increase blood concentrations of certain chemicals called cytokines and C-reactive proteins (Irwine, 2001 and Vgontzas, et al., 1998), indicating an inflammatory reaction.  The effect of unremitting low-grade inflammation may be to damage the inner walls of the arteries, which sometimes leads to vessel narrowing, high blood pressure, stroke, and heart disease (Irwine, 2001).  During truncated sleep, your heart might have to work harder, constricting blood vessels and increasing blood pressure even more, which could conceivably result in a heart attack or stroke (Martins, 2003). 

Sleep is as important to the human body as food and water, but most of us don’t get enough sleep.  Insufficient sleep or disruptions to the sleep contribute to adverse health effects. Numerous studies have also shown that even a little bit of sleep deprivation decreases efficiency and increases risk of disease, including cardiovascular disease. 

Initial changes to cardiovascular system from insomnia include hypertension, which is a potent co‑morbidity for other cardiovascular diseases. Hypertension has been linked to reduced sleep duration, with the highest correlation shown under 6 hours sleep per night (Gottlieb et al. 2006). However, associations have also been made between sleep of over 9 hours per night and hypertension and obesity. Furthermore this has not been supported at all in some studies and PPI in one older North American population actually showed a reduced risk of hypertension (Phillips, BOková and Enrigh, 2009.).

A study of 71,617 female health professionals found that sleeping fewer than five hours per night was associated with a 39 percent increase in the risk of coronary heart disease; even six hours per night showed an increase of 18 percent compared to sleeping eight hours per night (Najib, et al., 2003).  In an analysis of data on more than one million people, the levels of nearly all forms of death were two-and-a-half times higher for people who slept four hours or less compared to those who slept between seven and eight hours on average

A study of 71,617 female health professionals found that sleeping fewer than five hours per night was associated with a 39 percent increase in the risk of coronary heart disease; even six hours per night showed an increase of 18 percent compared to sleeping eight hours per night.  In an analysis of data on more than one million people, the levels of nearly all forms of death were two-and-a-half times higher for people who slept four hours or less compared to those who slept between seven and eight hours on average

Experimentally, sleep deprivation has been shown to negatively affect glucose metabolism and to enhance factors associated with Type 2 diabetes (Nilsson, et al., 2004).  Research has also shown that people who experience sleep disorders were as much as three times as likely to develop Type 2 diabetes (Kawakami, 2004).  Subjects in one study demonstrated impaired glucose tolerance for ten days after four hours of sleep deprivation (Spiegel, et al.,1999).  It is also found that sleep deprivation can play a role in obesity.  Sleep deficits bring about physiologic changes in the hormonal signals that promote hunger and, perhaps thereby, obesity (Spiegel, et al., 2004).  One study found that after two days of sleep curtailment the subjects had reduced levels of the fat-derived hormone leptin and increased levels of the stomach-derived hormone ghrelin.  These hormones are responsible for regulating hunger and appetite (Spiegel, et al., 2004).  These hormonal differences are likely to increase appetite, which could help explain the relative high BMI in short sleepers. 

 

Part 5 and more coming