Nearly 60 million Americans have difficulty either falling asleep or staying asleep. While researchers have explored various causes of sleep disorders, most of them stem from interruptions in the circadian rhythms of the human body.  

What are circadian rhythms?

Circadian rhythms are natural 24-hour cycles that regulate almost all physiological processes – hunger, thirst, mood, body temperature and when we are awake/asleep. Even though they are considered to be a biological clock, these rhythms are influenced by external stimuli such as temperature, traveling across time zones (Jet Lag) and exposure to light and dark, also referred to as our sleep-wake cycle.

Also playing a role are neurotransmitters (NTs). NTs are chemical signals that control these rhythms and physiological processes including our sleep-wake cycle. This cycle is controlled by the interaction between exposure to light and dark and neurotransmitters, ultimately acting like a switch or a seesaw.

The hypothalamus acts as a connecting pathway for neurotransmitters between the body and the brain and helps maintain homeostasis, or balance, throughout your body. It plays a role in major bodily functions such as appetite, thirst, blood pressure, body temperature, emotions, sex drive and sleep cycles. Located in the hypothalamus, the suprachiasmatic nucleus (SCN) acts as the body’s master clock – controlling when and how much of the “sleep hormone” melatonin is produced.

During the day excitatory NTs are at work, keeping us awake and alert. As we get closer to bedtime, about two hours prior, the seesaw begins to tilt and our inhibitory neurotransmitters start to take over. These excitatory and inhibitory neurotransmitters are emphasized by the exposure to light and dark. When exposed to light, cells in our eyes signal the SCN to inhibit melatonin production and utilize excitatory NTs. Around 9 P.M., when exposed to dark, our bodies start to produce melatonin and inhibitory NTs help put an end to wakefulness. At the end of REM sleep, our bodies flip the switch again and start pumping excitatory NTs to prepare us for the next day.

Lack of sleep could be detrimental

The average human spends about 1/3 of their life sleeping, but so many of us are coming up short.

Immunity. Not getting enough sleep takes a toll on your immune system making you vulnerable to catch a cold, the flu or other viruses easily.

Weight gain and skin problems. Lack of sleep decreases leptin, the hormone that makes you feel full and increases ghrelin, the hormone that drives hunger. Sleep helps hydrate and repair damaged skin cells while lowering cortisol levels to help keep pores healthy and clear.

Heart health, blood pressure and blood sugar. When you sleep, blood pressure and glucose levels decrease, giving your cardiovascular system a break.

Memory. While we sleep, the glymphatic system rids our central nervous system of toxins allowing our brains to process go through consolidation.

Coordination, reaction time and reflexes. Sleep deprivation is equivalent to intoxication. Our reaction times are slowed and coordination is impaired.

Mood, stress and inflammation. Not getting enough hours in throws off our hormones, negatively impacting mood. It also makes us more vulnerable to stress and therefore, inflammation.

What is a good night’s sleep?

The average adult benefits from 7-9 hours of sleep each night. The National Sleep Foundation states that a “full night’s rest” includes: sleeping at least 85% of the time you are in bed, initially falling asleep in 30 minutes or less, not waking up more than once a night and if you do wake up – being awake for no more than 20 minutes.

What can you do to get the amount and quality of sleep you need?

• Increase exposure to light during the day and decrease light exposure at night (including light from technology) to keep your circadian rhythm in check.
• Refrain from consuming sugar and caffeine after 3 P.M. – these can linger in your blood for 6—8 hours after consumption.
• Keep a consistent sleep schedule – wake up around the same time everyday and go to bed around the same time every night.
• Sleep in a cool, dark room to fall asleep faster and get more restorative sleep.
• Engaging in only relaxing activities in the bedroom helps our brain associate our bed with relaxation.
• Exercise regularly to ensure a good night’s sleep, just not before bed.
• Alcohol and tobacco products keep you from falling asleep and getting the restorative sleep you need.

If all else fails, try supplementing. Natural sleep-promoting supplements include: melatonin, valerian root, magnesium, lavender, L-theanine and 5-HTP.

References

Bulletproof Blog

Doctor Doni

Observer

Neuroscience News