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MANHEIM (Germany), Jan 21 — Dubbed the most depressing day of the year, “Blue Monday” 2025 falls on January 20. Although not without its critics, the concept is based on a falsely mathematical equation combining lack of light and holiday nostalgia. However, a study from the University of Mannheim suggests another hypothesis: that the famous “Monday blues” could actually be linked to a lack of sleep during the previous weekend.
Experts agree that people are sleeping less and less, including at weekends. It’s not always easy to get a good night’s rest on Saturdays and Sundays, between housework, shopping and socialising. Yet, according to a German study published in 2024 in the Journal of Organisational Behaviour, getting a good night’s sleep on our days off is crucial to our effectiveness at work.
Researchers at the University of Mannheim investigated how sleep quality over the weekend influences employees’ ability to mentally reconnect with their work on Monday, and to be productive throughout the week.
After all, many working people find it difficult to get back into their work on Monday morning, after being away from the office for 48 hours. Some even adopt aggressive attitudes on that day, which ease off as the week progresses, according to a paper published in 2021 in the Journal of Applied Psychology. For some, this phenomenon is even pathological. Researchers refer to it as “Monday morning syndrome,” a disorder characterised, among other things, by a lack of energy, irritability and difficulty concentrating.
Getting enough sleep to help get the week off to a better start
While the existence of this syndrome is disputed, there is no doubt that workers need to undergo a process of psychological reattachment, ie, mentally reconnecting with their professional goals, after the weekend. The authors of this latest research suggest that working people find it less difficult to reconnect with work on Monday when they’ve slept well over the weekend.
To test this hypothesis, the researchers monitored 310 German employees over a five-week period. They were asked to answer a questionnaire on their sleep quality and work reattachment on Monday, followed on Friday by another questionnaire about their level of fatigue and performance throughout the week.
It turned out that volunteers who had rested sufficiently over the weekend had less difficulty getting down to work on Monday morning. Conversely, those who had not slept enough on their days off found it harder to get back into the swing of things. Surprisingly, workers who had not slept enough on Saturday and Sunday due to various social obligations seemed not to experience this effect. They were able to get back into their work on Monday morning, despite their sleep deficit.
On the other hand, the study’s co-authors noted that the fatigue accumulated over the weekend did not directly affect employees’ performance. But, given that exhaustion is detrimental to long-term efficiency, it’s important to make rest a priority.
Indeed, that’s why it’s important to get enough sleep on Saturday and Sunday. It may seem trivial, but sleep is the key to making Monday a satisfying and productive day, rather than the worst day of the week. To achieve this, try applying the principles of the “quiet weekend” to keep Fridays low-key, and stop feeling guilty about resting. Without sufficient energy, you won’t get very far. — ETX Studio