Spring fatigue: where the tiredness comes from and whether kava helps

2025-03-28 · 5 min read

By the kava.fyi editorial team · Last updated: 28 March 2025

With the first warmer days, many people feel something quite the opposite of a surge of energy: drowsiness, irritability, difficulty concentrating. This phenomenon is often called spring fatigue, and for years it was treated as an obvious, seasonal biological fact. The latest research, however, calls for a more cautious look at the issue.

Does spring fatigue exist at all as a biological phenomenon

In 2026, the Journal of Sleep Research published a paper by Christine Blume and Albrecht Vorster that directly challenges the popular belief in spring fatigue as a distinct seasonal phenomenon. The researchers tracked a group of 418 adults from Germany, Austria and Switzerland for a year, between April 2024 and September 2025, regularly asking them about their level of tiredness, sleepiness, sleep quality and insomnia symptoms. Nearly half the participants, 47 percent, reported a subjective sense of spring fatigue. Repeated measurements, however, showed no statistically significant seasonal or monthly variation in fatigue, sleepiness or sleep quality over the year. In other words, people said they felt spring fatigue, but the objective data did not confirm that they actually slept worse or were more tired in spring than at other times of year. The authors suggest that the gap between the common belief and the data points instead to a cultural phenomenon, a label attached to ordinary, year-round tiredness specifically when the term "spring fatigue" happens to be popular and readily available in everyday language in a given country.

The study covered people from German-speaking countries, where the term "Fruhjahrsmudigkeit" has long been part of everyday and medical language, and a similar concept of spring fatigue is equally popular in Poland. This does not mean that no one feels worse in spring: it means rather that science has so far found no evidence for a distinct, biologically programmed mechanism that would strike specifically in March and April more strongly than in other months.

What actually does change in the body in spring

This does not mean nothing happens in spring at all. The lengthening day and changing light exposure affect the circadian rhythm, including melatonin secretion, and the body takes a little time to adjust to the new pattern of light and darkness. After months of shorter days, many people enter spring with lower vitamin D levels, which is sometimes linked to fatigue and low mood, although these mechanisms are still being researched rather than an established, simple cause-and-effect relationship. On top of that there is a purely practical factor: spring often brings more obligations, plans and pressure to "snap out of winter mode", which is itself a source of psychological strain, whether we call it spring fatigue or simply stress.

Where does kava fit into all this

Kava, a drink made from the root of Piper methysticum, is sometimes recommended as natural support in such moments because of its supposed anti-anxiety and calming effect. Here, though, the scientific picture is more complicated than it might seem. Earlier, smaller clinical trials, including the Pittler and Ernst meta-analysis from 2000 and a six-week study by Sarris and co-authors from 2013, showed a statistically significant advantage of kava over placebo in reducing anxiety symptoms. However, the largest study of this kind to date, published in 2020 in the Australian and New Zealand Journal of Psychiatry by Sarris's team, involved 171 people with diagnosed generalised anxiety disorder observed over 16 weeks, and found no statistically significant difference in the reduction of anxiety symptoms between the kava group and the placebo group. In the same study, abnormal liver function test results were recorded more often in people taking kava than in the placebo group, although no case met the criteria for drug-induced liver injury.

This means that the claim that kava "scientifically confirms" its effectiveness in relieving stress and fatigue is a considerable oversimplification. Some studies point to a real, if modest, anti-anxiety effect; others, better designed and larger, do not confirm such an effect. This is therefore an area where intellectual honesty requires admitting that the evidence is mixed, rather than glossing over it in favour of a more convenient narrative.

What is worth remembering before you reach for kava

Kava is metabolised in the liver, so it should not be combined with alcohol or with medications processed by that organ, including sedatives and antidepressants. It is also worth remembering the legal status: in Poland, kava is banned for sale as a food under a Ministry of Health regulation on designer substances; in Germany it is available only on prescription; and in the European Union it formally has no novel food status. The fact that something is natural does not automatically mean it is free of interactions or legal restrictions. People taking regular medication, who are pregnant or breastfeeding, and people with liver disease should avoid kava altogether without first consulting a doctor.

What actually helps you get through the spring slump

Whether we call it spring fatigue or simply natural tiredness, the fundamentals remain the same and have far stronger research support than any single supplement: regular sleep, exposure to natural daylight, outdoor physical activity and attention to diet. If a drop in mood or energy persists for a long time and clearly interferes with everyday functioning, it is worth consulting a doctor rather than assuming it is just "typical spring fatigue" that will pass on its own. You can read more about how kava affects sleep in the article kava and sleep, and about the mechanisms behind its effect on the nervous system in how kava works. If you are interested in the broader context of using kava against stress, also see cortisol and kava.