Substances and Sleep

Legal substances may be ruining our sleep.

Reviewed by Jessica Schrader

Key points

• Sleep issues may be a consequence of alcohol, cannabis, nicotine, caffeine, and sugar consumption.
• These substances affect sleep in different ways.
• Some people use stimulants to be awake and alert during the day but then cannot fall asleep.

For some of us, sleep is a battle. We may have a hard time falling asleep or staying asleep; we may even dread going to bed because we know we will be awake for hours. That belief about not sleeping may contribute to our not sleeping. We may pay attention to all the recommendations for good sleep hygiene (regular bedtime, limited screen time, cool and dark rooms, etc). However, we tend not to pay as much attention to several of the substances we regularly consume during the day. Many of us are caught in a cycle of using stimulating substances to function during the day and then other substances to relax, unwind, and sleep. The cycle becomes vicious.

Alcohol has a long-standing reputation for promoting sleep. The hot toddy allegedly has curative properties for a variety of ailments. But does alcohol really help with sleep? Alcohol may help a person to fall asleep faster but will have a negative effect later in the evening with more frequent awakenings because one does not enter Rapid Eye Movement (REM) sleep. Alcohol concentrates in organs and the bloodstream. As it metabolizes, a person wakes more often or remains in a lighter sleep.

• Mixing alcohol and prescription drugs is worrisome, especially with respect to side effects. Too many ignore the warning labels on prescription bottles.
• Alcohol tends to aggravate sleep apnea, leading to a higher number of breathing events. With a lot of alcohol in one’s system, a person may be more passed out than truly sleeping, which makes it harder to recover from a breathing event.
• Approximately ¾ of people with alcohol dependence/severe substance use disorder suffer from insomnia. Insomnia leads to more caffeine during waking hours.
• Alcohol itself in addition to the sugar added to cocktails raises blood sugar levels, which can interfere with sleep.

Cannabis (marijuana) may help a person to fall asleep faster but will have a negative effect later in the evening with more frequent awakenings because one does not enter REM sleep.

There’s a risk of a rebound effect: cannabis may help some with insomnia in the short term but exacerbates it in the long term.

The method of use partly determines the effects. Inhaling produces results more quickly. Ingesting it may have slower results, which may prompt a person to ingest more. This may lead to sleep interference. There are no guidelines about the amount of THC (the psychoactive component) in products nor are there standards of measurement. Too high a concentration of THC may affect dreaming.

The CBD (nonpsychoactive component) in cannabis may produce better results at lower dosages. Here, too, the method of use is important. Someone who uses a low dose of a CBD product may consume more to accelerate the onset of sleep. This may backfire. Cannabis may help promote sleep if sleep issues are connected to restless legs and chronic pain. The lack of research on the effects of cannabis with medications means we know little about their interactions

Nicotine is a stimulant that increases heart rate and blood pressure. A person who smokes before bed or during the night will spend more time in the lighter stages of sleep and less in REM. She will also experience more frequent awakenings or sleep disturbances. Nicotine contributes to sleep apnea and insomnia.

Withdrawal from nicotine can be quite uncomfortable; fatigue, irritability, headaches, depression, and nightmares are common. A person may have an alcoholic drink or use cannabis to overcome the stimulating effects or the withdrawal effects, which may create a difficult cycle.

Caffeine is a stimulant that increases heart rate and blood pressure. It is one of the most widely used stimulants in the world. In the U.S., it is estimated that nearly 90% of adults consume caffeine.

• Caffeine may help with focus but tolerance grows quickly, which prompts people to consume more in order to achieve desired results, which may cause jitteriness interrupting focus.
• Caffeine blocks the adenosine receptors that promote sleepiness.
• Intake reaches its peak in 30-60 minutes. Its half-life (time to eliminate half the drug is three to five hours.
• Adult consumption should not exceed 300-400 mg per day (equivalent of three to four mugs of coffee). Youth consumption should be fewer than 100 mg per day but popular energy drinks contain 200+ mg. Many youth are consuming several a day.
• Excessive caffeine may prompt a cycle: Too much caffeine --> alcohol or cannabis to calm/slow down --> interrupted sleep --> excessive caffeine intake during the day.

Refined/added sugar may trigger insomnia because it is high on the glycemic index. Sugar causes a rapid increase in blood sugar. Excessive sugar consumption creates a cycle: Spike in blood sugar-->release of insulin-->lower blood sugar-->increase in adrenaline and cortisol

• Sleep is crucial in the body’s regulation of blood sugars that do fluctuate during sleep. Added and refined sugars disrupt the regulation by overloading it.
• Sugars in whole fruits do not cause the same spikes because the fiber found in fruit slows absorption.

These substances are easily and readily available. Many people discount their seriousness because they are legal (at least in states that have legalized cannabis) and widely consumed. How we regulate our energy, focus, and rest through chemical means ought to give us all pause. It is too easy to become caught in these cycles of revving up and then trying to slow down every day. The effects of these cycles can be devastating.

To learn more about sleep, consider attending Nobel Conference 60 “Sleep, Unraveled” at Gustavus Adolphus College on Oct. 1 and 2, 2024. This conference is free and open to the public via livestream. It will bring together an interdisciplinary panel of experts to explore the centrality of sleep for human physical health and mental well-being. The conference will delve into the neurological and psychological processes of sleep, the cultural evolution of sleep practices, and the implications of a 24-hour convenience society that leads to permanent sleep deprivation.