As finals week looms, Yale students find themselves navigating late-night study sessions and caffeine-fueled sprints to the finish line. But what are the true costs of pulling an all-nighter?

The culture of all-nighters is a well-worn badge of honor for college students during finals week.  However, experts warn that sleep deprivation can impair cognitive function, emotional regulation and memory retention, which are critical for exam performance. 

“Pulling an all-nighter might seem productive, but your brain doesn’t work as efficiently without sleep,” Yale’s Dr. Klar Yaggi, director of the Sleep Medicine Program, said. “When you don’t sleep, memory, decision-making and mood regulation all take a hit.”

At Yale, the intensity of finals week often translates into late nights fueled by coffee and the glow of laptop screens at Bass Library. Students may justify skipping sleep with the hope of cramming in more information or finishing last-minute assignments. However, research and expert insights reveal that this approach can backfire.

One phenomenon that students often observe is a sudden burst of alertness in the early morning hours following an all-nighter. Yaggi attributed this to the natural circadian rhythm, which governs alertness and fatigue throughout the day.

“Even if you’re sleep-deprived, your circadian rhythm will signal increased alertness in the morning,” he said.

This “second wind” may provide a temporary sense of productivity, but the effects are fleeting.

Later in the day, as the circadian rhythm dips — usually in the early afternoon — students may experience extreme fatigue. According to Yaggi, this dip is an optimal time for a power nap.

Dr. Jacqueline Geer, an assistant professor in the Section of Pulmonary, Critical Care and Sleep Medicine at the School of Medicine, emphasized the critical role sleep plays in cognitive performance, stating that “memory consolidation is a complex process that is solidified during the deepest phases of sleep.”

Yaggi echoed Geer, stating that during sleep, especially during REM and slow-wave stages, the brain consolidates memories and processes information. Without these stages, he explained, students struggle to retain and recall what they have studied, putting them at a disadvantage despite the extra hours spent awake.

“After an all-nighter, students may experience increased distractibility, decreased memory consolidation and difficulty synthesizing information,” Dr. Susan Rubman said. “These are the exact skills needed for exams, and they’re impaired when sleep is sacrificed.”

The effects of sleep deprivation extend beyond memory. 

Yaggi highlighted that emotional regulation also suffers when students forgo rest. Sleep deprivation heightens activity in the brain’s amygdala, which controls emotional responses, while impairing the prefrontal cortex, which manages logical thinking. This imbalance, Yaggi said, leads to irritability, impulsivity and increased stress, none of which are ideal for students under pressure.

Stress and anxiety, which are common during finals, further complicate matters.

“Stress activates the body’s fight-or-flight system, making it harder to fall asleep,” Rubman said. “However, moderate anxiety can enhance performance, as long as it’s not compounded by sleep deprivation.”

Yaggi recommended incorporating brief naps, particularly during the natural circadian lull in the early afternoon. 

“A 20 to 30-minute nap can restore cognitive function better than caffeine,” he said. “But it’s crucial not to nap too long or too late, as this can interfere with nighttime sleep.”

Rubman highlighted the importance of proactive study habits, noting that starting earlier and maintaining a consistent sleep schedule allows students to retain information more effectively while minimizing stress. Planning ahead, she explained, not only supports better academic performance but also reduces the temptation to sacrifice sleep for last-minute cramming.

This proactive approach is particularly critical in managing the relationship between stress and performance, as outlined by the Yerkes–Dodson law.

“A moderate amount of anxiety can actually improve performance by heightening alertness and focus,” explained Rubman. “But too much or too little anxiety can have the opposite effect.”

In the absence of sleep, this balance becomes harder to achieve. Sleep deprivation amplifies emotional dysregulation, making it more likely for students to tip into the “too much stress” zone, where focus and reasoning are compromised.

For students who feel they must pull an all-nighter, both experts agreed on one key point: any sleep, even in small amounts, is better than none.

“All sleep is good sleep,” said Rubman. “Even a short nap before an exam can improve performance.”

In the race to succeed during finals week, Yale students may be tempted to forgo sleep in favor of more study time. Yaggi and Rubman make clear, however, that the smartest strategy for academic success might just be getting a good night’s sleep.

Only 30 percent of students sleep at least eight hours a night.