10Evidence B

Don’t make major decisions or send important messages late at night

People who stayed awake for 49.5 hours were asked to take part in risk decision experiments. When well-rested, they quickly learned to avoid high-risk options; after sleep deprivation, they repeatedly chose high-risk choices instead. The older a person is, the more pronounced this effect becomes. This study looked at the extreme scenario of two consecutive sleepless nights; it did not directly test how much impact a few fewer hours of sleep would have, but the overall trend supports postponing important decisions until the next day.

Cost

No cost at all. You simply postpone these tasks until afte…

Benefit

Thirty-four healthy participants completed the Iowa Gambling Task after going 49.5 hours without sleep. This t…

Cost

No cost at all. You simply postpone these tasks until after you’ve woken up.

Benefit

Thirty-four healthy participants completed the Iowa Gambling Task after going 49.5 hours without sleep. This task is a standard way to measure risk decision making. When well-rested, they quickly learned to steer clear of high-risk options; after sleep loss, they opted for high-risk choices far more often. Older participants showed a stronger response to this effect. This is the only study of its kind to date. The total number of participants was 34.

Original sources

Killgore, Balkin & Wesensten (2006). Impaired decision making following 49 h of sleep deprivation. Journal of Sleep Research. https://doi.org/10.1111/j.1365-2869.2006.00487.x

Open source link
Book note

The research focused on the extreme case of two nights of continuous sleep deprivation. There is no direct data on how ordinary people fare after staying awake until 2 a.m. The advice to avoid sending messages late at night is based on the authors’ personal experience (rated as Grade C evidence); it is perfectly fine to send such messages the following day instead.

My note