As the body uses energy, the brain produces adenosine, a chemical compound that influences the need to sleep. Adenosine is also available as a prescription drug, primarily used to treat irregular or fast heartbeats. Because adenosine receptors are found in multiple bodily systems, this chemical can affect the entire body. We explore the role adenosine plays in the human body, particularly in regards to sleep.
What Is Adenosine?
Adenosine is a neurotransmitter naturally found in the human body. Cells in the nervous system use neurotransmitters to transmit information among cells. Adenosine receptors are part of this chemical process, allowing adenosine to enter a cell and stimulate changes that enable the body to act out certain biological functions.
Adenosine promotes the sleep drive, or a person’s need for sleep. Research shows adenosine also plays a role in the immune system and can reduce inflammatory responses. Receptors for adenosine have also been found in the body’s circulatory, respiratory, and urinary systems.
When taken as a medication, adenosine can reduce heart rate and help manage irregular heartbeats. The administration of adenosine can reduce pain and lower blood pressure, especially in people undergoing surgery. In addition to being used as a treatment, adenosine may be given during a cardiac stress test to help medical professionals make heart-related diagnoses.
How Adenosine Affects Sleep
An increase in adenosine increases a person’s need for sleep, also called the sleep drive or sleep pressure. The sleep drive helps the body maintain sleep-wake homeostasis, or the right amount of sleep and wakefulness over time. The longer a person stays awake, the stronger their sleep drive becomes. When a person is deprived of sleep, the sleep drive prompts them to sleep more intensely and for a longer period of time the next time they sleep.
Adenosine is often found with a molecule called adenosine triphosphate, referred to as ATP. ATP is considered the “energy currency” of cells, as it stores and provides energy. As a person expends energy and ATP is broken down throughout the day, adenosine is released as a byproduct. Therefore, the more energy a person uses at a cellular level, the more likely they are to require sleep over time, due to the release of adenosine.
This relationship between ATP and adenosine is one mechanism through which increased activity leads to tiredness. The front of the brain, called the basal forebrain, releases adenosine as energy is used, increasing the need for sleep. Then, sleep likely allows the adenosine that has been accumulating throughout the day to clear out of the brain. Experts also suspect that the presence of adenosine helps prompt the deepest stage of sleep.
Recent research conducted with mice suggests adenosine also affects circadian rhythms. Circadian rhythms are multiple physical changes that occur over each 24-hour day, including the sleep-wake schedule. Melatonin is commonly named as a circadian rhythm hormone that promotes sleep by reacting to light and darkness. Similarly, adenosine appears to also influence sleep timing in response to light and darkness, as well as recent sleep history.
Adenosine and Caffeine
Caffeine, which naturally occurs in coffee and many teas, is the most commonly consumed stimulant in the world. Caffeine blocks adenosine, which is partly why ingesting caffeine can reduce sleepiness. Caffeine primarily works by entering the brain and blocking adenosine receptors, which makes it an adenosine antagonist. When adenosine is blocked from connecting with these receptors, a person feels less tired.
Blocking adenosine receptors with caffeine can do more than reduce tiredness. It also dilates and constricts blood vessels. Different people have different reactions to this type of impact on the cardiovascular system. In general, caffeine appears to increase blood pressure in people who do not consume caffeine regularly. Caffeine may also increase breathing rate, the need to urinate, and the need to defecate.
Adenosine Supplements for Sleep
Currently, adenosine is not available to the general public as a supplement. Adenosine is only available to medical professionals for use in certain clinical situations, such as to treat rapid heart rates or help with cardiac stress testing. Adenosine has not been used as a treatment to promote sleep because of the other effects it can have on a person’s heart and body.
However, preliminary research of mice suggests that certain drugs can promote sleep by acting on adenosine receptors, without also affecting body temperature, heart rate, or blood pressure. This early research suggests medications impacting adenosine receptors could be used to treat insomnia, but no drugs of this type are available to the public.
Perhaps confusingly, there are certain dietary supplements for sale that contain the word “adenosine” in their names, but these contain substances that differ from pure adenosine. Additionally, these supplements have not been studied in regards to how they affect sleep, and they are not recommended for sleep.
- Adenosine-5′-triphosphate (ATP): ATP is available as a dietary supplement usually geared toward people seeking increased exercise ability. ATP supplements are meant to counter fatigue and might improve physical performance.
- 5′ adenosine monophosphate-activated protein kinase (AMPK): Another dietary supplement, AMPK is often marketed as a way to increase metabolism and boost weight loss. Studies of mice suggest the enzyme AMPK may be useful in preventing negative health effects related to obesity and helping manage nonalcoholic fatty liver disease.
Frequently Asked Questions About Adenosine and Sleep
Does Adenosine Make You Sleepy?
As the brain naturally produces more adenosine throughout the day, a person’s need for sleep increases. For this reason, researchers have considered that either adenosine used as a medication or other drugs that affect adenosine receptors could promote sleep. But, as of now, neither adenosine nor compounds that act on adenosine receptors are available as a prescription or supplement.
Does Adenosine Increase REM Sleep?
Thus far, research studies that have explored the relationship between adenosine and REM sleep have shown conflicting results. An older research study found that drugs acting on certain adenosine receptors increase rapid eye movement (REM) sleep, the stage of sleep best known for dreaming. That said, more recent research conducted with mice suggests activation of adenosine receptors decreases rather than increases time spent in REM sleep. The same study showed that blocking adenosine receptors decreased REM sleep.
Adenosine does appear to increase time spent in another stage of sleep, called slow wave or deep sleep.
Is Adenosine a Sleep Hormone?
Adenosine promotes sleep, but it is a neurotransmitter, not a hormone. Hormones are chemicals created by endocrine glands. Adenosine is produced in the forebrain, not by an endocrine gland.
Is Adenosine Used For Insomnia?
No, adenosine is not currently used to treat insomnia, because of the effects it can have on a person’s heart. However, early research of mice suggests certain drugs that act on adenosine receptors may be useful for insomnia in humans, since they do not appear to affect body temperature or the heart. This type of drug or supplement is only being researched in animals and not generally available to humans.
If you have insomnia and are seeking treatment, it’s important to work with a doctor.
- Was this article helpful?