Going a day without sleep impairs attention, memory, and mood, and increases the risk of accidents. Don’t drive when very tired.
Effects
- Impaired attention, memory and mood.
- Slower reaction time.
- Risk of accidents: 24 hours awake affects performance like a blood alcohol level of 0.10% (a study in Occupational and Environmental Medicine).
- Microsleeps.
Body
Higher stress hormones and appetite.
Recovery
Sleep normally the next night.
Safety
Don’t drive.
Chronic loss
Raises the risk of health problems.
Measured effects of a missed night
After about 24 hours awake, performance drops. A widely cited 2000 study in Nature by Williamson and Feyer found that 17 to 19 hours without sleep impaired performance similar to a blood alcohol level of 0.05 percent, and 24 hours resembled about 0.10 percent, above the US legal driving limit of 0.08.
- Attention, memory and reaction time worsen, and mood becomes irritable.
- Appetite hormones shift: ghrelin rises and leptin falls, increasing hunger.
- Microsleeps of a few seconds occur, which are dangerous when driving.
- Drowsy driving contributes to about 100,000 police-reported crashes each year in the US, per NHTSA.
Recovery and safety
One night of recovery sleep, usually 9 to 10 hours, restores most function within a day or two. Avoid driving, operating machinery and major decisions when sleep deprived. Short naps of 20 minutes and caffeine give a brief boost. Chronic sleep loss is linked to higher risk of obesity, diabetes, heart disease and depression. Adults need 7 or more hours per night.
Measured effects of a missed night
After 24 hours without sleep, studies show attention and reaction time worsen to a level similar to a blood alcohol concentration of about 0.10 percent, which is above the US driving limit of 0.08. Memory, mood and decision making suffer, and appetite hormones shift, with ghrelin rising and leptin falling. Blood pressure and stress hormones can increase.
Recovery and safety
Most healthy adults recover after one or two nights of normal sleep. Avoid driving while very tired, since drowsy driving causes an estimated 100,000 crashes a year in the US according to the NHTSA. Caffeine helps alertness short term. Short naps of 20 minutes can help. Chronic sleep loss is linked with higher risk of heart disease and diabetes.
Effects after 24 hours awake
Staying awake for 24 hours impairs attention, memory and reaction time. Research cited by the CDC and published in Occupational and Environmental Medicine found that 17 to 19 hours without sleep produced performance equal to a blood alcohol concentration of 0.05 percent, and 24 hours is comparable to about 0.10 percent, above the US driving limit of 0.08. Mood worsens, with irritability and anxiety, and microsleeps of a few seconds can occur.
Body effects and recovery
Levels of cortisol and the hunger hormone ghrelin rise, appetite for sugary food increases, blood pressure and heart rate may climb, and immune markers drop. One night does not cause lasting harm in healthy adults. Recovery sleep is usually enough within one or two nights, and long naps late in the day may disturb the next night. Avoid driving, drink water, and keep caffeine moderate, with the FDA suggesting up to 400 mg daily for healthy adults. Chronic sleep loss is linked to heart disease and diabetes.
Based on data from the Centers for Disease Control and Prevention and the National Sleep Foundation
