Researchers at the University of Basel and the University Hospital of Bern report there is no measurable increase in tiredness during spring among German-speaking people. Psychologist and sleep researcher Christine Blume, a co-author of the study, told DW’s Science Unscripted podcast that participants were not demonstrably more fatigued in spring than in other seasons.
Blume and colleague Albrecht Vorster followed 418 people online for a year beginning in July 2024. Every six weeks participants rated how exhausted they had felt over the previous four weeks, along with daytime sleepiness and sleep quality. These repeated measures covered all seasons. Although roughly half the participants initially said they experienced Frühjahrsmüdigkeit (spring fatigue), the year-long data showed no springtime rise in reported exhaustion.
Common biological explanations for spring tiredness do not hold up in this dataset, the authors say. Hypotheses such as warmer temperatures causing blood-vessel widening, residual winter melatonin creating a seasonal surplus, or rapid changes in day length were not supported. From a chronobiological perspective melatonin is produced and broken down on a 24-hour cycle, so there is no seasonal accumulation; the study also found no effect of the speed of day-length change or of particular months on perceived fatigue.
Instead, the researchers argue that spring fatigue appears largely cultural and cognitive. The label itself offers a ready-made explanation for low energy and can shape how people notice and interpret symptoms. When sunny weather raises expectations of increased activity, people who feel low on energy are more likely to attribute that feeling to the season—an effect the authors describe as symptom reinforcement driven by expectations.
The study also found no association between spring fatigue and allergies, hay fever, or antihistamine use. Likewise, there is no scientific support for a distinct “winter fatigue”; while sleep duration can show small seasonal shifts, overall sleep need remains balanced across the year.
That said, seasonal factors can affect wellbeing in other ways. Seasonal Affective Disorder (SAD), a form of seasonal depression linked to reduced winter light, can include tiredness and low mood. Vitamin D deficiency, more common in winter due to reduced UV-B exposure, is also associated with persistent fatigue and muscle weakness.
Blume advises that people who experience burdensome, persistent tiredness should consult a doctor rather than assume it is simply seasonal. This article was originally published in German.