Epigenetic Changes in Sleep Loss May Contribute to Weight Gain

Sleep is absolutely essential to your body to remain healthy and for your brain to function optimally. If you have experienced excessive or increased daytime sleepiness, fatigue, moodiness, poor concentration, and/or decreased sex drive, you may be encountering signs that you are getting sufficient quality sleep.

There seem to be both long and short term consequences to losing sleep. Long term sleep loss and sleep disorders have been associated with a higher risk of many health issues including diabetes, obesity, depression, high blood pressure , heart attack, and stroke. Studies have shown that even small weekly shifts in sleep timing, or even just five nights in a row of short sleep, have been associated with an increased chance of gaining weight. in healthy humans. In fact, according to the CDC, adults who got less than 7 hours of sleep per night were more likely to report being obese and physically inactive.

Evidence shows that sleep duration has shortened over recent decades from to 6.5 hours a day . In fact, over two-thirds of US higher school students, who require at least 8 to 10 hours of sleep per night, reported getting less than 8 hours of sleep on school nights. Interestingly, at the same time, the CDC reports that obesity rates are also on the rise especially in teenagers.

Why do you need sleep? Sleep is a non negotiable or your body’s health. If you do not get adequate sleep in a specified amount of time, your body will force you to fall asleep, creating potentially dangerous situations, e.g. driving. Sleep is absolutely critical for your concentration and to be able to think clearly. Sleep also plays a role in consolidating memories and regulating emotions. Your immune system also works closely with sleep to reduce infection risk and improve responses to infections as well.

Your circadian rhythm is an internal 24-hour clock that tells when you sleep and when you wake up. This clock often works by responding to the amount of light available in your environment. Circadian rhythm sleep disorders often occur when there is a mismatch in the alignment of one’s internal circadian rhythm clock and actual sleep schedule. Those who work evening shifts or irregular shifts at their jobs are more prone to circadian rhythm sleep disorders. Jet lag and artificial light from screens (via phone, televisions, or computers) can further interfere with your body’s circadian rhythm. There has also been increasing evidence about seasonal affective disorder -- a mood disorder related to seasonal changes -- due to a shift in the amount of daylight available each day and mood disorders.

Even short term sleep loss can disrupt your circadian rhythm, leading to epigenetic changes in your tissues that can lead to loss of muscle mass and gain of fat mass. Epigenetic changes are changes that happen to gene expression of your DNA without adjusting the actual genetic code. Overall, sleep loss can lead to a state of skeletal muscle catabolism, or muscle breakdown. In subcutaneous fat tissue (fat right under the skin) on the other hand, short term sleep loss can reprogram the DNA methylation to promote anabolism, or building up of fat tissue. Additionally, research has found that sleep loss increases levels of cortisol, which is a catabolic hormone. Testosterone and nocturnal growth hormone levels are also lowered during acute sleep loss.

Additionally, poor sleep can also cause abnormal regulation of glucose in the body and increase the risk of becoming obese and/or developing Type 2 Diabetes (T2DM). In addition to impaired glucose regulation, poor sleep also affects appetite control and together has contributed to the increasing global rates of obesity and T2DM. As a reminder, insulin is a hormone made in the beta cells of your pancreas that helps to regulate your blood sugar and prevent it from getting too high. Studies looking at sleep deprivation showed an increase in insulin resistance and beta-cell dysfunction. Due to insulin resistance, insulin secretion is therefore impaired. It was found that after sleep deprivation, both fasting glucose (levels before your meal) and postprandial glucose (levels after your meal) in the body were increased. The effects of sleep deprivation on glucose metabolism have likely contributed to the T2DM and obesity epidemic today.

It is likely that sleep-related epigenetic changes in parents could be passed down onto future generations. Studies have discovered gene mutations likely affect regulation of the circadian rhythm and may play an active role in sleep disorders. Circadian rhythm regulated DNA methylation, histone modification, and chromatin remodeling, so it naturally follows that changes in epigenetics will affect your circadian rhythm. Research shows that mutations in the CLOCK, PER1, PER2, and PER3 may actually be the origin of sleep disorders of the circadian rhythm. In fact, the feeling of sleepiness is related to gene expression, and it is hypothesized that environment influenced epigenomics marker expression can lead to insomnia and excessive daytime sleepiness.

Did you known that being an “early bird” or a “night owl” can also be influenced by your epigenetics as well? This is called a diurnal preference. Early birds typically show more productivity in the mornings and go to sleep earlier, whereas night owls sleep later and perform best physically and mentally in the late afternoon hours. The expression of the Per3 and Nrr1d2 circadian clock-regulated genes can affect your diurnal preference.

The natural next question is - well what can I do? A different amount of sleep is recommended per age group, for example, children need more sleep than a typical adult. Ideally, most adults should aim for 7 or hour of high quality of sleep per night in a dark room. A recommended amount of sleep as directed by the Sleep Foundation is listed in Table 1 per age group.

Next, is to understand the importance of sleep hygiene. While there exist behavioral and cognitive therapies in addition to medications you can take for sleep, there are also everyday sleep habits you can implement to optimize getting healthy sleep. As seen in Table 2, some sleep hygiene habits you can establish include limiting screen time before bed, establishing consistent times for sleeping and waking, and dietary changes. These simple everyday changes can help to improve your sleep health.

References:

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