---
title: "What sleep loss does to reaction time: 300 ms"
description: "What sleep loss does to reaction time: typically 300 ms, really 250 ms to 600 ms. What is measured, and why it counts as a reaction."
url: https://atoneplace.net/reaction-time/reaction-time-fatigue/
site: "At One Place"
---

# What sleep loss does to reaction time

**What sleep loss does to reaction time: 250 ms–600 ms**

Reaction — a decision, via the brain

Sleep loss degrades reaction time in a distinctive way: the mean shifts only modestly while the slow tail explodes. What appears are lapses — trials of 500 milliseconds or more where attention simply drops out — and their frequency rises steeply with hours awake. This matters more than the average, because a driver whose mean reaction has worsened by 40 milliseconds but who now has a one-in-twenty chance of a half-second lapse is in a materially different situation.

## The numbers

- **Typical:** 300 ms
- **Range:** 250 ms to 600 ms
- **What it is:** Reaction — a decision, via the brain
- **What is measured:** Simple visual reaction after extended wakefulness or restricted sleep.

## Why this is a reaction

A reaction is a decision: signal in, processing, movement out. The floor for a human is around 150 milliseconds, and anything measured below about 100 ms is anticipation rather than response.

## Where it sits against everything else

*Reflexes at the top, reactions in the middle, design values off the end of the scale.*

- Vestibulo-ocular reflex — Reflex: 10 ms
- Knee-jerk (patellar) reflex — Reflex: 22 ms
- Latency added by your screen and mouse — Physical limit: 35 ms
- Blink reflex — Reflex: 40 ms
- Withdrawal reflex — Reflex: 90 ms
- Time a jab takes to land — Physical limit: 110 ms
- Sprint start reaction — Reaction: 140 ms
- Simple tactile reaction time — Reaction: 155 ms
- Simple auditory reaction time — Reaction: 170 ms
- Professional gamer reaction time — Reaction: 190 ms
- Formula One start reaction — Reaction: 200 ms
- Simple visual reaction time — Reaction: 250 ms
- How reaction time changes with age — Reaction: 250 ms
- What sleep loss does to reaction time — Reaction: 300 ms
- What alcohol does to reaction time — Reaction: 320 ms
- Recognition reaction time — Reaction: 340 ms
- Choice reaction time — Reaction: 380 ms
- Time to hit a 95 mph fastball — Physical limit: 400 ms
- Time a goalkeeper has on a penalty — Physical limit: 450 ms
- Time to play a 90 mph delivery — Physical limit: 500 ms
- Driver reaction to an expected event — Reaction: 850 ms

## How it varies between people

| What | Typical | Range | Kind |
| --- | --- | --- | --- |
| How reaction time changes with age | 250 ms | 190 ms–400 ms | Reaction |
| What alcohol does to reaction time | 320 ms | 260 ms–500 ms | Reaction |

## Common questions

### How long is what sleep loss does to reaction time?

Typically 300 ms, with a real range of 250 ms to 600 ms. Simple visual reaction after extended wakefulness or restricted sleep.

### Is that a reflex or a reaction?

Reaction — a decision, via the brain. A reaction is a decision: signal in, processing, movement out. The floor for a human is around 150 milliseconds, and anything measured below about 100 ms is anticipation rather than response.

## Related pages

- [How reaction time changes with age](https://atoneplace.net/reaction-time/reaction-time-by-age/)
- [What alcohol does to reaction time](https://atoneplace.net/reaction-time/reaction-time-alcohol/)
- [A reflex is not a reaction](https://atoneplace.net/reaction-time/reflex-vs-reaction/)
- [Stopping distance at every speed](https://atoneplace.net/reaction-time/stopping-distance/)
- [Measure your own reaction time](https://atoneplace.net/tools/reaction-time-test/)

## Sources

- Typical range compiled from manufacturer specifications — At One Place (/about/)