Best Hack For Increased Deep Sleep
Best Hack For Increased Deep Sleep
Lower core body temperature and increase serotonin levels too!
Neuro Athletes,
When it comes to “biohacking” your sleep, it seems that the single most important (and confusing) variable for most folks is deep sleep levels. I’ve addressed this topic a few times in previous articles and podcast episodes and yet it is still a mystery to most people.
My quest for better sleep has been ongoing for the past 10 years. I used to sleep only 5.5 hours per night as I was trained to do so as a triathlete. I was totally overworked and almost burned out after doing crazy hours at training and at work that my sleep quality was so poor it was basically non-existant. Working hours reached, at their worst, nearly 100 per week – average was easily over 60. So where did I cut the time for working out and socialization?
You got it right, sleep.
Since 2016 I had been trying out different supplements, technologies, mattresses, pillows, beds, bedrooms, and all kinds of herbs for achieving better sleep. But nothing can make it better if you have only limited time to spend in the bed. So that particular feature was the first step in optimizing sleep: simply spending more time in bed and changing my life in such a way that it made sleeping more possible.
This article delves deep into the secrets of better deep sleep with a the latest findings in Glycine and its effects on deep sleep.
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Sleep is crucial to maintaining physical, cognitive, and emotional health, of which a lack thereof has been highly associated with negative consequences in terms of health (such as obesity, diabetes, cardiovascular disease, poor immunity, poor mental health, and neurodegeneration), occupational errors and injuries, and major accidents. Some notable events partly attributable to poor sleep include the tragedies of the Three Mile Island and Chernobyl nuclear plant, the Exxon Valdez oil spill, and the space shuttle Challenger Explosion[1].
A recent meta-analysis revealed a 22% prevalence of insomnia in the general population[2]. However, this number rose to 35.7% during the COVID-19 pandemic[3]. The manifestations of insomnia generally extend beyond nighttime sleep to alter the sense of well-being and impair the ability to carry on daytime activities. In a study focusing on the experience of insomnia, participants who were asked to describe their insomnia experience affirmed expected daytime impairments such as fatigue, irritability, and decreased concentration[4]. Emerging evidence has shown that glycine supplementation could potentially alleviate insomnia[5].
Glycine
Glycine is one of the twenty amino acids that serves as a building block for protein synthesis in the body. As it is produced endogenously, glycine is regarded as a non-essential amino acid. Nevertheless, glycine is also obtainable through diet. Individuals were estimated to obtain approximately 1.5-3g of glycine per day from rice or protein-rich food like meat and fish[6].
Aside from its involvement in protein building, glycine also acts as a neurotransmitter in the central nervous system. It exhibits an inhibitory effect via the glycine receptors, which helps reduce pain[7]. However, glycine also acts on the N-methyl-D-aspartate (NMDA) receptor to produce an excitatory effect, which is crucial for neuroplasticity that is critical for learning and memory[8]. Other biological effects of glycine include anti-inflammatory, cytoprotective, and immunomodulatory properties[9], and have been demonstrated to decrease plasma triglycerides, abdominal fat accumulation, and blood pressure in sucrose-fed rats[10], as well as enhance sleep quality in individuals[11][12].
Glycine And Sleep
According to the National Sleep Foundation (NSF), the elements of sleep quality included sleep latency (amount of time to fall asleep), wake time after sleep onset (amount of time awake at night), and sleep efficiency (proportion of the time in bed spent sleeping). Specifically, good sleep quality is one with a sleep latency of ≤30 minutes, two or fewer awakenings, and a sleep efficiency of ≥85% per night[13].
In terms of sleep architecture measures, the NSF has proposed that good quality sleep for adults should comprise a higher proportion of rapid eye movement (REM) sleep and deep sleep (N3 sleep stage), and lesser light sleep (N1 and N2 sleep stage)[13].
In one study, fifteen healthy participants aged 24-53 years who reported continuous sleep dissatisfaction, experienced a reduced feeling of fatigue when administered 3g of glycine within one hour before bedtime[11]. Similarly, in a subsequent study, eleven participants between the ages of 30 and 57 years, who also had insomniac tendencies, experienced shorter sleep latency, improved sleep efficiency, and decreased daytime sleepiness after ingesting glycine of a similar dosage before bedtime relative to placebo[12]. Furthermore, an assessment of sleep architecture using polysomnography revealed that following glycine ingestion, participants had a shorter latency to sleep onset and also to N3 stage sleep as compared to placebo. In other words, they were quick to enter deep sleep. Interestingly, glycine ingestion did not appear to alter the overall sleep architecture among the participants[12].
There are two ways glycine may affect sleep — by helping to lower core body temperature and increasing serotonin levels in the brain.
Glycine helps lower body temperature
Sleep is regulated by two process models: homeostatic regulation and circadian regulation. In particular, circadian regulation is an internal daily biological clock that works based on a 24-hour rhythm. This process, regulated by the master circadian pacemaker located in the suprachiasmatic nucleus (SCN) of the hypothalamus, controls physiological processes like body temperature, heart rate, muscle tone, and hormone secretion that rise and fall every 24 hours[14].
During the sleep phase, the core body temperature (CBT) reduces as body heat dissipates through the distal parts of the body, such as the fingers and the feet. The reduction in CBT is regarded to facilitate sleep and was shown to decrease with every transition from N1 to N3 sleep[15].
In an animal study, glycine supplements triggered a drop in core body temperature in mice during the sleep phase. Furthermore, an attempt to elucidate the mechanism of action revealed that administered glycine crosses through the blood-brain barrier and exhibits its effect through the NMDA receptor in the SCN and causes peripheral vasodilation, an event that facilitates body heat loss[16].
Glycine increases serotonin levels in the brain
The sleep hormone melatonin is synthesized primarily at night, specifically about two hours before bedtime. It induces a state of quiet wakefulness (lying on the bed with the eyes closed) that helps promote sleep in individuals. The synthesis of melatonin involves serotonin as its precursor. A study has shown that oral administration of glycine increases serotonin in the prefrontal cortex, the brain region involved in memory consolidation during sleep[17]. These findings suggest that glycine may indirectly affect melatonin production by increasing the supply of serotonin.
Adverse Events Relating To Glycine Supplementation
To identify possible adverse effects involving glycine supplementation, a study administered 9g of oral glycine to twelve individuals for 7 days[18]. Results showed that three out of twelve patients experienced digestive symptoms such as abdominal pain and soft stool. Notably, these events occurred when the patients ingested glycine before bedtime, whereas no observable adverse events occurred when glycine was taken 30 minutes after breakfast or lunch. This suggests that the mild adverse effect may have been due to the high osmotic pressure state due to the consumption of glycine on a relatively empty stomach. In a different study, gastrointestinal discomfort with accompanying nausea and vomiting has been reported with higher doses of glycine supplementation of approximately 60g per day, thus indicating a risk of glycine toxicity at high dosages[19].
What does this mean for you?
In sum, a low dose of glycine supplementation (i.e., 3g) within one hour before bedtime may help improve sleep quality and alleviate daytime sleepiness, particularly among individuals with insomniac tendencies. Nevertheless, caution must be taken with higher doses as it has been demonstrated to induce digestive complications and, in severe cases, glycine toxicity manifested as nausea and vomiting.
Until next time,
Louisa x
Improve Your Fitness Through Sleep
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