Human study · Research · 8 Nov 2026
In 24 healthy adults kept awake for 48 hours, pupil timing and visual responses slowed, while a short task and resting pulse did not
Source: Sleep
What the research found
Sleep published a laboratory study on 8 November 2026. Krzysztof Rozanowski and Marcin Jankowski kept 24 healthy adults awake for 48 hours under supervision. Each person had one rested baseline and eight sessions during the deprivation. Measures were the pupil response to light, spontaneous pupil unrest, pattern-reversal and flash visual evoked potentials, a Stanford sleepiness rating, a short psychophysiological task, and resting blood pressure and heart rate. The abstract used here does not give age or sex. Light-reflex latency, reaction duration, and time to the smallest pupil diameter changed early. Later, pupil diameter during redilation fell. The pupillary unrest index rose on the first night and stayed high. Pattern-reversal P100 and N135, and flash N3 and P3, peaked later after prolonged wakefulness. Sleepiness ratings rose across the 48 hours. The short task and the resting cardiovascular measures stayed comparatively stable. This is a description of signals during forced wakefulness. It is not a sleep rule. DOI 10.1093/sleep/zsag293. Not medical advice.
Evidence level: Human study. A study in people, but an association isn't proof of cause.
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