It’s one of the first warm days of the year: crocuses push through the soil, cappuccinos taste of new beginnings and winter seems behind us. Yet many people in German-speaking countries report a yearly slump known as Frühjahrsmüdigkeit — spring fatigue.
Researchers from the University of Basel and the University Hospital of Bern say there is no empirical evidence for such a seasonal increase in tiredness. “We found that people are not measurably more fatigued or tired during spring than any other season,” said study co-author Christine Blume, a psychologist and sleep researcher, on DW’s Science Unscripted podcast.
Blume and her co-researcher Albrecht Vorster followed 418 participants online for a year beginning July 2024. Every six weeks participants rated how exhausted they had felt in the previous four weeks, along with daytime sleepiness and sleep quality. The repeated measures covered all seasons. Although about half of participants initially reported suffering from spring fatigue, the longitudinal data showed no uptick in fatigue during spring months.
Common biological explanations — warmer temperatures widening blood vessels, lingering winter melatonin levels causing sleepiness, or rapid changes in day length — do not hold up, the authors argue. From a chronobiological standpoint melatonin is produced and broken down in a 24-hour cycle, so there is no seasonal surplus. The study found no effect of the speed of day-length change or of specific months on perceived exhaustion.
Instead, the researchers conclude spring fatigue appears to be largely cultural and cognitive. The label “spring fatigue” gives people a ready explanation for low energy, shaping how they notice and interpret symptoms. When sunny weather raises expectations of activity, people who feel low on energy are more likely to perceive and attribute it to the season — a form of cognitive dissonance and symptom reinforcement.
The study also found no link between spring fatigue and allergies, hay fever, or antihistamine use. There is likewise no scientific proof for a distinct “winter fatigue” — while sleep duration may vary slightly by season, overall sleep need remains balanced across the year.
That said, seasonal conditions can affect wellbeing in other ways. Seasonal Affective Disorder (SAD), a form of seasonal depression related to reduced light in winter, can include tiredness and low mood. Vitamin D deficiency, more common in winter due to limited UV-B exposure, is also associated with persistent fatigue and muscle weakness.
Blume advises that if tiredness is burdensome, people should consult a doctor rather than assume it is simply seasonal. This article was originally published in German.