A good night's sleep is incredibly important for your health. In fact, it’s just as important as eating healthy and exercising. Unfortunately, the Western environment is interfering with natural sleep patterns.People are now sleeping less than they did in the past, and sleep quality has decreased as well.
1. Poor sleep can make you fat
Poor sleep is strongly linked to weight gain. People with short sleep duration tend to weigh significantly more than those who get adequate sleep (1, 2). In fact, short sleep duration is one of the strongest risk factors for obesity. In one extensive review study, children and adults with short sleep duration were 89% and 55% more likely to become obese, respectively (3). The effect of sleep on weight gain is believed to be mediated by numerous factors, including hormones and motivation to exercise (4). If you’re trying to lose weight, getting quality sleep is absolutely crucial.
Studies show that sleep-deprived individuals have a bigger appetite and tend to eat more calories. Sleep deprivation disrupts the daily fluctuations in appetite hormones and is believed to cause poor appetite regulation (2, 5). This includes higher levels of ghrelin, the hormone that stimulates appetite, and reduced levels of leptin, the hormone that suppresses appetite (6).
Sleep is important for various aspects of brain function. This includes cognition, concentration, productivity and performance (7). All of these are negatively affected by sleep deprivation. A study on medical interns provides a good example. Interns on a traditional schedule with extended work hours of more than 24 hours made 36% more serious medical errors than interns on a schedule that allowed more sleep (8). Another study found that short sleep can negatively impact some aspects of brain function to a similar degree as alcohol intoxication (9). On the other hand, good sleep has been shown to improve problem-solving skills and enhance memory performance of both children and adults (10, 11, 12).
Sleep has been shown to enhance athletic performance. In a study on basketball players, longer sleep was shown to significantly improve speed, accuracy, reaction times and mental wellbeing (13). Less sleep duration has also been associated with poor exercise performance and functional limitation in elderly women. A study in over 2,800 women found that poor sleep was linked to slower walking, lower grip strength and greater difficulty performing independent activities (14).
It’s known that sleep quality and duration can have a major effect on many health risk factors. These are the factors believed to drive chronic diseases, including heart disease. A review of 15 studies found that people who don’t get enough sleep are at far greater risk of heart disease or stroke than those who sleep 7–8 hours per night (15).
Experimental sleep restriction affects blood sugar and reduces insulin sensitivity (16, 17). In a study in healthy young men, restricting sleep to four hours per night for six nights in a row caused symptoms of prediabetes (18). These symptoms resolved after one week of increased sleep duration. Poor sleep habits are also strongly linked to adverse effects on blood sugar in the general population. Those sleeping less than six hours per night have repeatedly been shown to be at an increased risk of type 2 diabetes (19, 20).
Mental health issues, such as depression, are strongly linked to poor sleep quality and sleeping disorders. It has been estimated that 90% of people with depression complain about sleep quality (21). Poor sleep is even associated with an increased risk of death by suicide (22). Those with sleeping disorders like insomnia or obstructive sleep apnea also report significantly higher rates of depression than those without (23).
Even a small loss of sleep has been shown to impair immune function (24). One large two-week study monitored the development of the common cold after giving people nasal drops with the cold virus (25). They found that those who slept less than seven hours were almost three times more likely to develop a cold than those who slept eight hours or more. If you often get colds, ensuring that you get at least eight hours of sleep per night could be very helpful. Eating more garlic can help as well.
Sleep can have a major effect on inflammation in your body. In fact, sleep loss is known to activate undesirable markers of inflammation and cell damage. Poor sleep has been strongly linked to long-term inflammation of the digestive tract, in disorders known as inflammatory bowel diseases (26, 27). One study observed that sleep-deprived people with Crohn's disease were twice as likely to relapse as patients who slept well (28). Researchers are even recommending sleep evaluation to help predict outcomes in individuals with long-term inflammatory issues (27).
Sleep loss reduces your ability to interact socially. Several studies confirmed this using emotional facial recognition tests (29, 30). One study found that people who had not slept had a reduced ability to recognize expressions of anger and happiness (31). Researchers believe that poor sleep affects your ability to recognize important social cues and process emotional information.
Along with nutrition and exercise, good sleep is one of the pillars of health. You simply cannot achieve optimal health without taking care of your sleep.