When should you study?

What the science says

Circadian rhythms regulate your body temperature, cortisol levels, and alertness in a cycle that repeats roughly every 24 hours. Cognitive performance — especially for tasks requiring working memory, attention, and complex reasoning — peaks when your core body temperature is rising, typically in late morning for most people.

A landmark 2012 study by Roenneberg et al. showed that chronotype is highly heritable and shifts predictably over a lifetime: teenagers naturally sleep and wake later (explaining why 8am classes feel brutal), while adults shift earlier as they age. About 25% of people are morning types, 25% are evening types, and 50% fall in the intermediate range.

Research by Goldstein et al. (2007) found that studying during your non-optimal time of day reduced test performance by 3-5 percentage points on average — equivalent to losing a few nights of good sleep. Scheduling studying during your peak window is one of the few study habits with direct experimental support.

Related resources

• Spaced Repetition vs Cramming — the research on when and how often to study
• How Students Study: 2026 Report — what time most students actually study (9:14pm peak)
• Average Study Hours by Major — how much your peers are putting in
• Study Schedule Generator — build a schedule around your peak hours