Start by knowing what can move
Simple reaction time has a floor set by biology. Light has to reach your eye. Your brain has to see it, decide it is the signal, and send a command down to your finger. That round trip never drops below about 100 milliseconds in anyone. Typical adults land near 231 ms on lab equipment, according to Woods and colleagues (2015).
So the useful question isn't how to make your nervous system faster, because mostly you can't. It is how much of your current score is avoidable loss, and for most people the answer is quite a lot. Your state, your technique and your equipment cause far more day-to-day change than any training programme will.
What actually works
Sleep
Sleep wins by a wide margin. Reaction speed is one of the first things to suffer when you lose sleep, and the damage adds up. In Van Dongen and colleagues (2003), people who slept only six hours a night for two weeks ended up thinking as poorly as people who had skipped sleep for two whole nights.
Yet they rated themselves as only slightly off. That is the trap. Short sleep night after night hurts your performance and your ability to notice it at the same time. If you want a faster number tomorrow, sleep does more than anything else you can try, and it costs nothing.
Time of day
Alertness follows a daily rhythm. For most people it dips in the early afternoon and again in the small hours. Testing at your peak instead of your low point can move a score more than a month of practice would. It also means a morning result and a late-night result can't be compared fairly. The difference tells you about your body clock, not your ability.
Warming up
Your first run of anything is nearly always your worst, because part of it goes to learning what the task wants. Two or three throwaway rounds before the run you count remove a good chunk of that. This isn't cheating. Without a warm-up, your first rounds measure how unsure you are about the task, not how fast you react.
Hardware
Hardware matters more than people expect. A standard screen costs you about 8 ms compared with a fast gaming screen, because the image can't change until the screen redraws. A 125 Hz mouse can sit on your click for up to 8 ms, where a 1000 Hz mouse holds it for about 1. Wired beats Bluetooth.
None of this makes you faster. It just stops your equipment from making you look slower. Our guide on online reaction test accuracy covers the full chain.
Posture and readiness
Rest your finger lightly on the button instead of hovering above it. That takes the travel distance out of the measurement. Keep your eyes near where the signal will appear, so it lands in your central vision. Breathe out and stay loose, because tension slows your movement down instead of speeding it up.
What does not work, or barely does
Most brain training
Practising a reaction test makes you better at that reaction test. Whether that helps with anything else is a separate question, and the evidence for far transfer is weak. We wrote about this in what the evidence says about brain training.
If your goal is a better number on this page, practice will get you there. That is mostly because you learn the task, not because you get faster in general.
Reaction-time supplements
This category is mostly marketing. Caffeine is the one exception with real evidence behind it, and even its effect is modest. It helps if you are short on sleep or in an afternoon slump. If you are rested and drink coffee every day anyway, it does almost nothing. Tolerance builds, so someone who drinks coffee all day gets less from a pre-test cup than someone who doesn't.
Chasing a personal best
A single fast round is mostly luck. Woods and colleagues found within-person variability of about 40 ms. Your own trials scatter that much around your own average without anything changing. If you run twenty times and keep the best one, you are keeping your luckiest round and calling it progress. Compare medians across sessions instead.
Video games
Video games sit somewhere in between. Action gamers do tend to score better on fast visual tasks, but nobody has settled which causes which. Where studies do show gains, they are strongest on tasks that look like the game and fade on tasks that don't.
The thing that looks like improvement but is not
The fastest way to a low number is guessing. You start your click before the signal appears, timed to the rhythm of the earlier rounds. It produces impressive figures and measures nothing. A well-built test blocks this by making the wait random and throwing out any click that lands early. Our reaction time test does both.
Watch for it in yourself. If your score jumps while your canceled rounds pile up too, you are not getting faster. You are gambling more often, and only the winning bets get scored.
The honest version of the same instinct is useful, though. In real life, most of what looks like superhuman reaction is prediction. An experienced driver or goalkeeper is not reacting faster. They react earlier, because they read the cue sooner.
A sensible routine
If you want a number that improves and means something, here is what we suggest:
- Sleep properly.
- Test at the same time of day, when you are alert.
- Use the same device and the same mouse every time.
- Warm up with two rounds you throw away.
- Keep the tab in front.
- Record the middle score of a full set, not your single best click.
Then look at the trend over a week or two, not from session to session. Most people find that their honest baseline is better than the number that first alarmed them.