Kava and sleep quality: how much we sleep, and how

2022-09-30 · 5 min read

By the kava.fyi editorial team · Last updated: 30 September 2022

Did people used to sleep longer

There is a common belief that we sleep less today than we used to, before the age of smartphones, artificial light and constant overstimulation. It is a convenient story, but hard to back up with data, since nobody attached an electroencephalograph to people two hundred years ago. One of the few studies that tries to answer this question empirically looked at three pre-industrial communities, the Hadza of Tanzania, the San of Namibia and the Tsimane of Bolivia, whose way of life comes closest to conditions before the industrial revolution. A study published in 2015 in the journal Current Biology found that members of these communities slept, on average, between 5 hours 40 minutes and 7 hours 6 minutes a night, that is, less, not more, than the average resident of a developed country.

For comparison, an analysis of records from a popular sleep-tracking app, cited by Professor John Groeger, found an average sleep time of 7 hours 50 minutes. In other words, the belief that we sleep less today than in the past looks like a myth. We sleep longer than communities living without artificial lighting and electronics, just of poorer quality.

How much sleep do we actually need

Recommendations for optimal sleep length usually fall in the range of 7 to 8 hours a night for adults, though some analyses allow for as much as 9 hours. Almost all of them agree on one thing, though: sleep needs vary strongly from person to person. The key factor is not just the number of hours but sleep quality, specifically how much time the body spends in deep, non-REM sleep. It is in this stage that real recovery happens: breathing slows, blood pressure and body temperature drop, muscles relax, and the body repairs tissue more intensively.

Where sleep disorders come from

Sleep disorders are usually divided into three categories: dyssomnias, that is, primary disorders, parasomnias, or episodic disturbances, and secondary disorders, which result from other conditions, both physical and psychological. Causes of secondary sleep disorders include cardiovascular disease, hormonal disturbances and psychological conditions, including depression. A very common, though often underestimated, factor is also chronic stress.

Stress itself is not a negative phenomenon, it is a natural adaptive mechanism of the body. The problem starts when it lasts too long or is too intense. That reduces the body's ability to fall into deep sleep, which in turn disrupts the circadian rhythm and weakens resilience, including resilience to stress itself. This creates a vicious circle, in which worse sleep leads to greater vulnerability to stress, and more stress to even worse sleep. On top of that come seemingly minor factors: lack of exercise, heavy meals eaten in the evening, or irregular sleep times, which further worsen glucose metabolism and the regulation of appetite hormones such as leptin and ghrelin.

What is known about kava and sleep

Kava (Piper methysticum) has long been associated with deep relaxation, but it is worth separating what research confirms from what is merely a traditional observation. A study in rats with disturbed sleep, published in the journal Psychopharmacology, found that kava extract increased delta-wave activity during non-REM sleep, the stage responsible for recovery, and shortened sleep latency, the time needed to fall asleep, at a dose of 300 milligrams per kilogram of body weight. Notably, unlike flunitrazepam, a benzodiazepine used in the same study as a reference point, kava's effect was not reversed by flumazenil, a benzodiazepine receptor antagonist. This suggests kava works through a different mechanism than classic sleeping medicines in that class.

This is an important caveat: the results above come from animal studies, not from large clinical trials in humans looking directly at sleep architecture. So it is fair to say kava is associated with the potential to improve deep sleep quality, not that it guarantees it. The mechanism that may lie behind this involves kavalactones acting on GABA type A receptors in the brain, also described in the context of their anxiolytic effect. A reduction in anxiety on its own makes falling asleep easier, independent of any direct effect on sleep stages.

Kava, alcohol and caution

If you reach for kava with better sleep in mind, it is worth keeping a few caveats in mind. Kava is not a medicine and should not be treated as a substitute for treating insomnia that has a medical cause, especially when insomnia is a symptom of depression or another disorder requiring its own diagnosis. Nor should kava be combined with alcohol or with medicines metabolised in the liver, including sedatives or anti-anxiety drugs, since loading the liver with two substances at once increases the risk of adverse effects. You can read more on this in the article on kava and the liver.

What you can do today

Before reaching for any sleep aid, it is worth first looking at the basics: regular sleep times, avoiding heavy meals right before bed, and limiting exposure to artificial light in the evening. If you want to see how kava affects your evening routine, it is best to try it a few hours before you plan to fall asleep, watching how you respond rather than expecting an instant effect the first time. It is also worth understanding the wider context of how this plant works, for instance in the piece on kava and GABA and the article on kavalactones.

It is also worth remembering that different kava cultivars vary in the proportions of individual kavalactones, that is, their chemotype, and this affects the character of the effect: some chemotypes are considered more relaxing and sedating, others more balanced, supporting conversation rather than calm. If you are specifically after the relaxing aspect, it is worth paying attention to this variation instead of treating kava as one uniform product. As with other natural approaches to supporting sleep, the effect tends to be gradual and dependent on regularity, rather than a single dose taken before an important event.