A new Tohoku University study suggests the brain may form stronger long-term memories when slightly tired, challenging the belief that mornings are best for learning. (Image: Pexels)
People have always said that the best time to learn new things is in the early morning when your brain feels fresh and alert. But a recent study from Tohoku University challenges this idea. According to the research, your brain might actually form stronger long-term memories when you’re slightly tired, rather than when you’re fully energised.
Your brain doesn’t learn the same way all day
The researchers examined how brain cells respond to identical stimuli at different times throughout the day. They found that these responses — especially those related to learning — vary dramatically based on the body’s natural circadian rhythms.
Using genetically modified rats, the team observed that short-term neural responses were weakest just before sunrise, the time when the animals were at their most fatigued. The research showed that this was also the time when the brain had the strongest ability to create long-term memories through a process called long-term potentiation (LTP). LTP plays a key role in forming lasting memories and learning new skills.
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The surprising role of tiredness — and adenosine
A key molecule identified in the study is adenosine, which builds up in the brain throughout the day and promotes sleepiness. Beyond making you feel tired, adenosine appears to prime the brain for deeper memory formation.
The scientists found that when they stopped adenosine from working in tired rats, their improved ability to store long-term memories went away. This hints that a tired brain might be set up to learn and remember information more.
What this could mean for humans
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Because the research was done on nocturnal animals, the “pre-sunrise” learning window in rats roughly corresponds to early evening or late afternoon in humans — a time when many people naturally begin to feel mentally worn out after a full day.
This doesn’t mean you should exhaust yourself before studying. The results point to the idea that being a bit tired rather than alert could be a surprisingly good state for learning tasks that need focus and long-term memory.
But sleep still matters
The study’s authors emphasise that this is not a recommendation to stay up late or cut down on rest. Sleep still plays a key part in cementing memories, fixing nerve cells, and bringing back brain power. Learning may happen when you’re tired, but retaining that learning requires adequate sleep afterward.
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A shift in how we think about learning
The study also notes that it focused on the visual cortex, not the hippocampus — the brain’s primary memory centre — so more research is needed. Human chronotypes (whether you’re a morning person or a night owl) may also influence when your brain learns best.
These discoveries shake up the old idea that “early morning is best” and give us a fresh take on getting things done. If you’ve ever found it hard to pick up new stuff in the morning but easier at night, your brain’s makeup might be behind it.