The science: Lavender has been shown to have sleep benefits. Sniffing lavender essential oil before bed has been shown to increase quality of sleep, reduce anxiety, promote deep sleep (Karadag et al., 2015; Cho et al., 2013; Goel et al., 2005). It has also been shown to decrease the time taken to fall asleep and increase self-satisfaction with sleep (Lee & Lee, 2006).
Sleeping with a weighted blanket has been found to provide sleep benefits The weight must not be too light or heavy (15-30 lbs is typical for adults), and should be evenly distributed throughout the fabric.
Studies on insomniac adults have shown that sleeping with a weighted blanket increased the quality of sleep and decrease agitation (Ackerley et al., 2015). The pressure from these weighted blankets produces a calming affect by reducing physiological levels of arousal.
The science: Melatonin is produced in the brain by the pineal gland around 2 hours before bedtime. Researchers found that taking low doses of melatonin in the evening made it easier to fall asleep and reach deep sleep. The subjects who took the low dose melatonin did not feel groggy from it the next morning (Zhdanova et al., 1995).
Put electronic devices away 2 hours before bed or wear blue wavelength-blocking glasses. Researchers have found that people wearing blue wavelength-blocking glasses for 3 hours prior to bedtime experienced a significant improvement in sleep quality and mood (Kimberly & James, 2009).
The science: Electronic devices emit high concentrations of blue light. Blue light adversely affects production of the sleep producing hormone melatonin – the chemical that regulates sleep – more than any other wavelength. A 2015 study examined the effects of blue light on sleep and found those that used a blue light devises like a cell phone before bed took longer to fall asleep, experience less REM sleep, took longer to wake up and were sleepier once they woke up. (Chang et al., 2015).
Low levels of vitamin D has been linked to poor sleep quality. You can absorb vitamin D through sunlight or through your diet. If you’re not able to regularly get vitamin D, consider taking vitamin D3 supplements, especially during winter months when you are less likely to get the sun exposure you need.
The science: Studies suggests that vitamin D deficiency is associated with sleep disorders (McCarty et al., 2014). Vitamin D receptors are located in parts of the brain typically associated with sleep. A study performed in 2017 found that vitamin D supplements made it easier to fall asleep, increased sleep quality, and increased sleep duration in 20-50 year old people with sleep disorders (Majid et al., 2017).
The science: Melatonin is a chemical produced in the brain’s pineal gland at night time in order to regulate the body’s natural sleep/wake cycle. When there is even the slightest amount of light in your bedroom, your melatonin production is partially inhibited which interferes with your sleep. (Reiter, 1991).
White noise helps you fall asleep by masking background noise that would otherwise prevent you from sleeping. For this reason, a white noise machines have been found to help people sleep.
The science: A 2001 study found that white noise made it easier to fall asleep and stay asleep (Borkowski et al., 2001). Another study found that white noise made it easier to stay asleep in otherwise distracting environmental noise, such as with the noise of the intensive care unit (ICU) (Stanchina et al., 2005).
Sunlight during the day, especially in the morning, helps regulate your body’s sleep cycle. If your circumstances prevent you from getting sunlight, consider an at-home light therapy lamp which emulates sunlight throughout the day.
The science: The body’s circadian rhythm is a 24 hour internal clock which controls the natural sleep/wake cycle. It is controlled in the brain by the hypothalamus and is affected by outside factors such as environmental lightness and darkness. Studies have found that getting sunlight every morning acts to restore the human circadian rhythm (Smith & Trinder, 2005).
Why are we awake during the day and sleep at night? Why do you feel more tired as the day progresses? There are two major process involved in regulating the sleep-wake system.
Circadian Rhythm (Biological Clock)
The circadian rhythm uses environmental signals to create a corresponding internal daily rhythm. Circadian process (including sleep, feeding, temperature, and activity patterns) are primarily controlled in the brain by the suprachiasmatic nucleus, a small region within the hypothalamus (Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem., 2006). The main environmental driver of the circadian rhythm is the change in light, since this generally reflects the time of day. Light enters the eye and reaches the retina, which then transmits the light signal to suprachiasmatic nucleus (SCN). The SCN then coordinates the daily cycles of sleep, feeding, activity, and corticosteroid hormone secretion. Exposure to light in the mornings cues the suprachiasmatic nucleus to send signals to increase the body’s temperature and inhibit melatonin- processes that help you wake up. When it gets dark, the suprachiasmatic nucleus decreases core body temperature and instructs the pineal gland to secrete melatonin, a hormone which helps further regulate the circadian rhythm. Lightness and darkness are so important to the circadian rhythm that being exposed to even a small amount of light during the night can suppress melatonin secretion and increase body temperature.
Artificial lighting and electronic devices are new advances in our evolutionary history and our bodies have not yet been able to adapt. Light is composed of many different wavelengths, which are each associated with a particular color. Blue light (which is found in high concentrations in our electronics) adversely affects production of the sleep producing hormone melatonin more than any other wavelength. By keeping indoor lighting dim at night, wearing blue light blocking glasses at night, using an app like f.lux on computers and tablets, and avoiding looking at electronic screens 2 hours before bedtime, you can combat the adverse effects of blue light at night.
Another important biological component of sleep is homeostasis. Homeostasis is generally defined as a collection of processes for an organism to maintain a stable internal environment. When optimal conditions are changed, homeostatic regulatory mechanisms kick in to maintain a balanced equilibrium. Sleeping is a compensatory response to the preceding waking episode. The longer you have been awake, the stronger the drive to fall asleep (Vyazovskiy et al., 2017). Once you fall asleep, the pressure to sleep begins to dissipate until eventually you are likely to wake up. During a waking episode, glycogen (one of the body’s energy sources) is depleted and adenosine (a sleep-regulating neuromodulator) is accumulated in the forebrain, which inhibits the reticular activating system (the part of the brain that keeps you awake). By inhibiting the reticular activating system, the build up of adenosine makes you feel more sleepy (Schwartz and Roth, 2008). In general, the pressure is specific to non-REM sleep (otherwise known as “deep” sleep). After an adequate night containing non-REM sleep, adenosine is removed and you will awaken feeling ready to begin the new day.
Top image credit: Credit: National Institute of General Medical Sciences
The science: Studies have shown that moderate and regular physical activity has therapeutic and sleep promoting benefits. The most beneficial effect comes from aerobic endurance training and acute exercise that lasts for more than an hour. On the other hand, be careful not to take things too far. High intensity, exhaustive, long duration exercise may disrupt sleep by decreasing REM sleep and increasing wakefulness (Sherrill et al., 1998).