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Last week, I opened an athlete’s training log to a harrowing entry. It was bad, with two of the scariest symptoms for an athlete: persistent tiredness on uphills and a heavy, foggy brain. What was it? Gosh, hopefully not the start of overtraining syndrome, or mono, or some severe illness. We couldn’t just hope it would pass any longer.
After talking about the importance of getting to a doctor, we discussed possible causes. In that conversation, there was a revelation . . . the athlete had taken Nyquil for 12 consecutive days.
Nighttime congestion from a cold led the athlete to self medicate, and the persistent symptoms led to persistent self medication. I poked around, and this type of story seems relatively common. While a 2013 survey from the CDC found that just 4.1 percent of Americans use prescription sleep aids consistently, the National Sleep Foundation reports that 25 percent take some sort of medication to help them sleep, most without doctor consultation.
Anecdotally, I hear about athletes taking prescription sleep aids like Ambien or Lunesta sometimes, but hear more about over-the-counter options like Nyquil, Benadryl, Tylenol PM, melatonin or even cannabidiol (CBD). The running website LetsRun has dozens of threads on sleep aids and running performance (in between threads of high schoolers saying terrible things about pro runners). The triathlon website Slowtwitch is the same (in between threads saying that your bike seat is too high). It seems like a question that athletes think about a lot, but is most often discussed in hushed whispers on internet message boards.
Runners might take sleep aids for anything ranging from diagnosed insomnia to a cold to just trying to catch a bit of shut-eye before a big race. But what do the different options mean for athletic performance?
Before trying to answer that question, a reminder: Talk to your doctor about any health concerns you have, and avoid self medication whenever possible. That being said, we know lots of athletes are batting this question around in their brain, so let’s delve into the research.
What are some common sleep aids and how do they work?
Melatonin is a hormone primarily released by the pineal gland in the brain which plays a role in sleep-wakefulness cycles, with a large role played by the onset of darkness (why you should consider putting away your phone and computer before bed and getting a good book instead). Since it’s naturally produced by the body, most doctors and studies indicate that side effects are minimal for most people.
CBD is the second-most abundant compound in the cannabis plant, after THC. But unlike THC, it’s non-psychoactive. I imagine Seth Rogen and Snoop Dogg just canceled their Trail Runner magazine subscriptions. The exact mechanisms of CBD for sleep are still being investigated, but proponents often say that it can help sleep and anxiety when taken at night. CBD was taken off the banned-substances list by the World Anti-Doping Association, unlike THC, which is banned in-competition.
Nyquil, Benadryl and similar substances induce drowsiness via antihistamines (doxylamine succinate for Nyquil, diphenhydramine for Benadryl). When the immune system is active like during a cold, histamines induce an inflammatory response (in the nose, it causes sinus congestion). Antihistamines can thus ease symptoms of allergies, but the sedative effect is usually considered a secondary use due to the tendency of some antihistamines to cross the blood-brain barrier. There, they disrupt another function of histamines—regulating sleep and wakefulness cycles.
Pharmacological agents are grouped into benzodiazepines (like Xanax and Valium) and non-benzodiazepines (Ambien and Lunesta), along with a few other variations. Since these substances are all prescribed by a doctor, I’ll avoid going over their function in detail, since my doctor knowledge is limited mostly to the greatest hits of Dr. Dre.
What are factors to consider in their impact on athletic performance?
A 2016 review article in the Frontiers of Physiology journal outlined a somewhat unsatisfying answer—we don’t know enough about how sleep aids affect athletic performance. The authors indicate that most studies have confounding factors, primarily with study populations being those suffering from insomnia or non-athletes. Plus athletic performance usually isn’t high on the totem pole of important things to consider about sleep aids for most researchers. However, the researchers cite an NCAA survey that nearly 20 percent of athletes reported using sleep aids at least periodically, so they point toward the importance of further study.
Regarding melatonin, a 2001 study in the International Journal of Sports Medicine found no change in performance in the treatment and control groups after a 5mg dose the evening before activity. Notably, it also found no change in sleep duration or quality. A 2003 study in the journal Ergonomics found that daytime melatonin use didn’t change performance on a cycling time trial later in the day, though it did reduce alertness. The effectiveness of melatonin generally varies across studies (see this 2014 article for a review of the literature).
One important factor to consider is the half-life of sleep aids, or how long it takes for the concentration of the substance to be half of the original dose. Most pharmacological resources indicate that many drugs are considered to have cleared the system around five half lives. According to a 2012 article, melatonin has an elimination half-life of around two hours. So it makes sense that the studies aren’t finding much impact on performance even if it had some impact to begin with (which is also debatable). Delayed or extended release melatonin may have different effects since the start of that half-life clock would be pushed back.
Regarding CBD, research is limited to back-up claims about its benefit for sleep patterns. A 2019 case study analysis in the Permanente Journal found that 48 of 72 patients dealing with anxiety and related conditions at a psychiatric hospital had improved sleep scores in the first month taking CBD. A 2018 study in the Frontiers of Pharmacology Journal found no change in sleep relative to the control group in healthy subjects. Both note that more study is needed.
Performance-wise, CBD may have beneficial impacts on pain thresholds and anxiety in athletes according to a 2018 article in the Clinical Journal of Sports Medicine, but that needs to be investigated further as well. Long-term impacts are not fully understood, including the effect of CBD on hormones, as outlined by this 2017 study in the journal Cannabis and Cannabinoid Research (which I’m guessing has a horse in this race). My big conclusion is that if you want your kids to have a job, suggest that they become a CBD researcher instead of faking of a photo so they get a spot on the water-polo team at USC.
I couldn’t find any studies on the impact of drowsiness-inducing antihistamines like those found in Nyquil and Benadryl on running, but several sources agree that the sedative effect would hurt athletic performance. The warning labels say you shouldn’t operate heavy machinery, like THOSE DIESEL PISTONS (flexes quads). Thus, what matters is how long the substances are in your system. Let’s return to our good friend, the half life.
The active ingredient in Benadryl (and Tylenol PM) has an elimination half-life of approximately nine hours for young adults according to a 1990 article in the Journal of Clinical Pharmacology. I saw other reports pegging it around that number, though it varies based on the source. Nyquil’s active ingredient has an elimination half-life of around 10 hours.
Here’s the important part that the athlete taking Nyquil 12 days in a row needed to see. That longer half life means that these medications remain in the system for around two days at least. In addition, most experts say to avoid antihistamines to treat sleep issues, especially long term (see here from Baylor, along with numerous other sources).
Some prescription sleep aids have shorter half lives, but those should not be considered without the recommendation of a doctor due to potent side effects (one 2012 study of more than 30,000 people in The British Medical Journal found a threefold increase in mortality risk even when prescribed 18 or fewer sleeping pills a year, though those findings are controversial and far, far beyond the scope of this article).
What’s the takeaway?
The takeaway is to talk to your doctor. But coaching and message boards show that not everyone will do that no matter how many disclaimers my former-lawyer brain makes me include. So short of that, based on the studies and pharmacology, it would make sense that over-the-counter antihistamine-based medications used for sleep like Nyquil likely impact performance the next day due to their longer half-lives (if we assume that the sedative effect is bad for performance). That overlaps with what most of the message boards say, but message boards also say that A Star is Born was a good movie, so take that with a grain of salt.
Melatonin seems to have limited impacts on performance, and it clears the system rather rapidly. However, its effectiveness varies. Anecdotally, I have heard of athletes using melatonin to establish sleep cycles when traveling overseas, and even some that have used it before competition.
Not enough is known about CBD to make a definitive statement, but more studies are coming out all the time. Anecdotally, some athletes swear by it to help with sleep and anxiety. Others say that it’s an expensive placebo.
Prescription sleep aids should be taken only when recommended by a doctor for serious conditions.
Sleep is really, really hard for lots of people. There are no easy solutions for a topic like this, and I understand that this article likely raised a few more questions than it answered. Everyone is different, but based on the research, for my periods of sleeplessness, I think I’ll focus on sleep hygiene (limiting light exposure and similar interventions), which studies like this one from 2017 in the International Journal of Exercise Science say improves sleep quality in athletes. I’ll definitely pass on the Nyquil, and maybe do a few extra hours of reading instead.
—David Roche partners with runners of all abilities through his coaching service, Some Work, All Play. His book, The Happy Runner, is about moving toward unconditional self-acceptance in a running life, and it’s available now at Amazon.