Marijuana and Sleep: The Facts
Marijuana can have a powerful effect on sleep. Some say cannabis or “weed” helps with falling asleep and many users develop a habit of smoking right before bed.
Marijuana is probably best known for its ability to induce drowsiness. In other words, it can make you feel sleepy. In addition, people who smoke before bed often report a decrease in the time it takes to fall asleep and an increase in restfulness of the sleep itself.
A lack of dreams is also commonly reported by nighttime marijuana users, which demonstrates marijuana’s unique effect on the different stages of sleep, specifically REM sleep.
Sleep is one of the more mysterious aspects of human health, and scientists are still unravelling many of the details. However, decades of research on marijuana and sleep have revealed a number of interesting findings.
What scientists now know is that cannabinoids – the active ingredients in cannabis, such as THC and CBD – actually mimic the effects of natural compounds in the body called endocannabinoids. What’s more, studies show that endocannabinoids act as natural regulators of the sleep/wake cycle.
As a result, sleep seems to be just another one of the many biological functions controlled – at least in part – by the body’s endocannabinoid system. And by interacting with this biological system, marijuana can affect your sleep in a number of ways.
Stages of Sleep
To understand how marijuana affects one’s sleep, it is important to understand how sleep works.
Sleep is an active, naturally occurring state of the brain. During sleep, the brain cycles through different stages of activity, also known as the stages of sleep. The two basic stages of sleep are rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep. However, NREM sleep is broken down into stages 1 through 3, while REM sleep is considered stage 4. Dreaming usually occurs during REM sleep.
Stage 1 – Occurs mostly in the beginning of sleep and lasts between 5 to 10 minutes. A very light stage of sleep in which one can be awakened easily. If aroused, the person will usually believe that they were fully awake.
Stage 2 – A period of light sleep in which heart rate slows and body temperature drops. Lasts for approximately 20 minutes as the body prepares to enter deep sleep.
Stage 3 (slow-wave sleep) – Also known as deep sleep, delta sleep or slow-wave sleep. Brain waves are very slow as blood flow is directed away from the brain and towards the muscles, restoring physical energy. Lasts for approximately 30 minutes and one may feel disoriented for a few minutes if aroused.
Stage 4 (REM sleep) – The longest stage of sleep in which most dreams occur. Characterized by eye-movement and increased breathing and heart rate. Heightened brain activity during this stage causes vivid dreaming, but legs and arms are immobilized. The combination of brain wave excitement and muscular paralysis is why REM sleep is sometimes referred to as paradoxical sleep.
Over the years, many studies have set out to determine the impact that marijuana has on sleep. And the findings seem to explain why many choose to smoke before bedtime. That is, marijuana can act as a sleep aid by decreasing the amount of time it takes to fall asleep.
But what happens after you fall asleep? Interestingly, studies show that marijuana can also affect the different stages of sleep; specifically, slow-wave sleep and REM sleep.
As it turns out, slow-wave sleep and REM sleep are somewhat intertwined. Studies have found that ingestion of THC – the psychoactive compound in marijuana – leads to an increase in slow-wave sleep. An increase in slow-wave sleep leads to a decrease in REM sleep, which explains why marijuana users often experience less dreams.
Another interesting finding is the REM rebound effect that is commonly observed when marijuana use is stopped. Common characteristics of an REM rebound are restlessness and overly vivid dreaming, which are a result of the brain spending more time in the REM stage than it usually would. An increase in REM sleep has also been linked to depression and symptoms of bipolar disorder.
Taking everything into consideration, it would appear that nighttime marijuana use does in fact disrupt one’s sleep. While it is tempting to view this as a negative, research suggests marijuana could offer a few health benefits as well.
For example, in addition to helping users fall asleep faster, the effect of marijuana on slow-wave sleep may also be viewed as beneficial. Experts say that the most damaging effects of sleep deprivation are caused by inadequate slow-wave sleep. For instance, research has shown that reduced slow-wave sleep can be a powerful predictor of high blood pressure in older men. Thus, users who suffer from a lack of overall sleep may actually benefit from using marijuana.
On the flip side, a lack of REM sleep should be viewed as a potential drawback of nighttime marijuana use – although experts are still unsure of what REM sleep actually does for the brain. The fact that brain cells are highly active during REM sleep suggests that it does not play a role in the rest and repair of the brain. What’s more, research shows that REM sleep deprivation has little to no impact on learning and memory, with some studies showing that it may even improve memory. A lack of REM sleep has also been found to alleviate symptoms of depression. Even still, experts are confident that REM sleep has some sort of positive effect on the body, while it remains to be determined what exactly it may be.
All in all, marijuana users should take caution when using marijuana as a sleep aid. However, the use of commonly abused substances such as nicotine and alcohol are definitely not recommended before bedtime – both of which are known to disrupt the sleep cycle as well as exacerbate pre-existing sleep disorders. On the other hand, studies have shown that nighttime marijuana use may be beneficial for the treatment of sleep disorders such as insomnia and sleep apnea.