Why Your Reaction Time Matters More Than You Think, Especially as You Age

By Your Health Magazine Contributor

Your Health Magazine Contributor

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Why Your Reaction Time Matters More Than You Think, Especially as You Age

A car ahead of you brakes hard. A glass starts to tip off the counter. Your foot catches the edge of a rug. Each time, what happens next comes down to a fraction of a second: how fast you notice the problem and how fast your body responds.

That fraction of a second is your reaction time. Most of us never think about it, but it affects how safely we drive and how well we keep our balance. Some research even links it to how long we live. It also changes as we get older, though not always in the way people expect.

What reaction time actually is

Reaction time is the delay between seeing, hearing or feeling something and responding to it. Your eyes pick up the signal, your brain works out what it means, and then it tells your muscles what to do. All of that happens faster than a blink.

For a simple task, like pressing a button when a light turns green, most adults react in about 200 to 300 milliseconds. That’s between a fifth and a third of a second.

Real life is usually harder. When you have to decide what to do instead of just reacting, researchers call it choice reaction time. Is that car stopping or turning? Should I step left or right? Those decisions add time, and they’re where age shows up the most.

How age changes your reaction time

The slowdown starts earlier than most people would guess.

In 2014, researchers at Simon Fraser University in Canada studied more than 3,300 players of the strategy video game StarCraft 2, aged 16 to 44. Response speed in the game started to slow at around age 24. But the older players made up for it. They used shortcuts and smarter strategies, so their overall performance held up.

Everyday reaction time changes more slowly than that headline suggests. A study of more than 7,000 adults in the UK found that simple reaction time barely changed until around age 50. Choice reaction time was different. It slowed a little at a time across adulthood.

Reactions also tend to get less consistent with age. You might be quick one moment and slow the next. The slow moments are the ones that cause trouble on the road or on the stairs.

So age plays a part, but it isn’t the whole story. A lot of what slows people down can be changed.

Why reaction time matters for your health

Driving

Reaction time is one of the biggest safety factors behind the wheel. A well-known review of driver braking studies found that drivers take about 0.7 seconds to hit the brake when they know a signal is coming. When something happens by surprise, like a person stepping into the road, it takes about 1.5 seconds.

At 60 miles per hour, you travel about 88 feet every second. In 1.5 seconds, your car covers roughly 130 feet before your foot even reaches the brake pedal, and that’s before the car starts slowing down. Every bit of extra delay adds more distance.

Falls

According to the CDC, more than one in four adults aged 65 and older falls each year. Falls are the most common cause of traumatic brain injuries, and they cause most hip fractures.

Reaction time is one factor that can influence whether someone recovers from a stumble or loses balance. An Australian study of 477 older adults tested how quickly people could step onto a panel when it lit up. People who had fallen before were about 150 milliseconds slower than people who hadn’t. Out of everything the researchers measured, that stepping test was the strongest predictor of falls.

A window into your overall health

A Scottish study followed 898 people from age 56 to age 70. Those with slower reaction times had higher all-cause mortality during follow-up. In that study, adjusting for reaction time also substantially reduced the association between IQ and mortality.

That doesn’t mean a slow reaction time causes health problems. It’s more likely a sign of how well your brain and nervous system are working overall, which is why it’s worth paying attention to.

What you can do about it

You can’t stop getting older, but many of the things that slow your reactions are within your control.

Stay active. A 2022 study of 792 adults over 60 in China found that people who got more exercise in their free time reacted faster on a thinking-based reaction test than less active people: about 0.99 seconds compared with 1.11 seconds. Walking, dancing, swimming and sports all count. Housework didn’t show the same benefit.

Get enough sleep. Being tired slows you down more than most people realize. In a Stanford study, college basketball players who slept longer for several weeks improved their reaction times from 311 to 275 milliseconds. Poor sleep also causes lapses, those moments when your mind goes blank for a split second.

Practice balance and quick stepping. Since stepping speed is so closely tied to falls, it’s worth keeping your feet quick. 

Get your eyes checked. You can only react to what you see clearly. In the same falls study, trouble seeing edges and shapes in low contrast was also linked to falls. Regular eye exams help catch problems early.

Cut down on distractions. A phone, a busy conversation or loud music all pull your attention away. When your attention is split, your reactions are slower, especially when you need to make a choice.

Keep track of it. It’s easy to check your reaction time at home. You can use this reaction time test that takes under a minute. Testing now and then on the same device gives you a baseline, so you can spot changes over time. One test won’t tell you much, but a pattern over weeks or months can.

If you notice a sudden change in your reaction speed, balance or coordination, talk to your doctor. Some medications, sleep problems and health conditions can slow your reactions, and many of them can be treated.

The bottom line

Reaction time does slow with age, but not as quickly or as much as many people fear. The bigger differences often come from things you can change, like how active you are, how well you sleep and how focused you are. Paying attention to your reaction time is a simple way to protect your safety now and your health in the years ahead.

Sources

1. Thompson, J.J., Blair, M.R., & Henrey, A.J. (2014). Over the Hill at 24: Age-related decline in reaction times in a video game task. PLOS ONE.
   
2. Der, G., & Deary, I.J. (2006). Age and sex differences in reaction time in adulthood. Psychology and Aging.
   
3. Green, M. (2000). “How Long Does It Take to Stop?” Driver perception-brake times. Transportation Human Factors.
   
4. Centers for Disease Control and Prevention. Facts About Older Adult Falls.
   
5. Lord, S.R., & Fitzpatrick, R.C. (2001). Choice stepping reaction time and falls risk in older people. The Journals of Gerontology: Series A.
   
6. Deary, I.J., & Der, G. (2005). Reaction time explains IQ’s association with death. Psychological Science.
   
7. Physical activity and cognitive reaction time in older adults in China (2022). Frontiers in Public Health.
   
8. Mah, C.D., et al. (2011). Sleep extension and athletic performance in college basketball players. Sleep.