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Your reaction time offers surprising insights into your overall health, from brain function to risks of early death. As we age, it’s natural for reaction speeds to slow, which is one reason athletic performance starts to decline around our 30s. However, research suggests that maintaining average response speeds is a sign of strong brain health, even as we age. In fact, these reaction times reveal much more, reflecting your cardiovascular health and overall risk of premature death.

Why Reaction Time Matters for Health

“Some people naturally react quicker, even before age-related changes become visible,” explains Simon Cox, a professor specializing in brain and cognitive ageing at the University of Edinburgh. “A slowing of reaction time suggests a buildup of age-linked deterioration. It tells us a lot about biological systems working together.”

How to Measure Your Reaction Time

One easy way to measure your reaction time at home is through the “ruler drop test.” This test requires only a ruler and a helping hand. Here’s how it works:

1. Sit comfortably in a chair and rest your arm on a table, letting your wrist hang off the edge.
2. Position your hand with the thumb and forefinger facing upward.
3. Have someone hold a ruler vertically, with the “zero” mark aligned with your thumb.
4. Without warning, they drop the ruler, and you must catch it as quickly as possible.

The distance the ruler falls before you catch it indicates your reaction time. A result of less than 7.5 cm is excellent, while between 7.5–15.9 cm is above average. Catching the ruler at 15.9–20.4 cm is average, and anything above 20.4 cm is below average. More than 28 cm suggests a poor reaction time.

The Link Between Slower Reactions and Health Risks

Research has shown that slower reaction times can be tied to a greater likelihood of age-related diseases and premature death. One study highlighted a direct connection between slower responses and an increased risk of mortality from various causes. Reaction time is also linked to specific health risks such as heart disease, stroke, breathing disorders, and even dementia.

It has even been found that slower reactions can contribute to an increased risk of falls and the loss of independent living abilities, which are serious health concerns as we age.

However, Cox emphasizes that a single reaction test doesn’t offer a complete picture. “Differences in gender, genetics, fitness, lifestyle, and personality all contribute to wide variability in individual reaction times,” he notes. What truly matters is tracking your reaction speed over time. Significant declines over a decade or more can be a cause for concern.

Understanding What Declines First: Brain or Body?

The reaction test hinges on two key components: the brain’s ability to quickly recognize the stimulus (like a falling ruler) and the body’s ability to act upon that command. Researchers have discovered that physical ability tends to decline before cognitive abilities do. Even if the brain recognizes the stimulus quickly, the body may take longer to respond.

Professor Alaa Ahmed from the University of Colorado Boulder suggests that this is due to a decrease in the efficiency of fast-twitch muscle fibers and mitochondria, which power the muscles. As we age, our bodies find fast movements more energy-draining, which impacts our reaction speed.

How the Nervous System Still Performs Well in Older Adults

Despite the decline in physical ability, research shows that healthy older adults can still maintain a strong nervous system. Professor Matthew Pain from Loughborough University found that elderly individuals were still able to send “move” commands effectively in response to a loud noise, indicating that their reflex capabilities were intact.

Pain adds, “The nervous system in healthy elderly individuals is still efficient. They could react fast enough to be disqualified for false starts in the Olympics, though they might not sprint with the same speed.”

Digital Tools for Testing Reaction Time

In addition to physical tests, you can also track your reaction time using digital tools like the Human Benchmark Reaction Time Test. This game measures how quickly you can react to a visual stimulus, such as clicking a box that changes color. By tracking performance over time, you can detect significant drops in reaction speed, which may signal early signs of sensor breakdowns or delayed brain processing.

Reaction Time and Early Signs of Dementia

One particularly interesting finding is the relationship between reaction time and dementia. Recent studies have shown that losing the ability to detect visual patterns can be an early warning sign of dementia, often detected years before cognitive symptoms arise. “With age, brain signal transmission becomes slower,” Cox explains. “When the brain chooses to act, the nerves must deliver the message quickly to the muscles, but these too age.”

How to Boost and Maintain Your Reaction Time

While reaction time naturally declines with age, there are ways to slow this process. Engaging in exercises and activities that challenge both the body and mind can help maintain quick reactions. Professor Pain suggests “dual task training,” where you perform a physical activity while also engaging in a mental task. Examples include walking while turning your head, balancing while reciting words, or even playing games that combine physical and cognitive challenges.

Even interactive TV fitness classes can help improve coordination and response time. “These activities sharpen your ability to detect and react meaningfully,” Pain says.

Both Cox and Pain agree that staying physically active, learning a musical instrument, or continuing intellectually stimulating activities like puzzles or board games can help maintain your reaction speed. Cox explains, “Fast-paced sports drills can train your brain and body to react quicker. Engaging socially and mentally slows cognitive aging across different complex mental functions.”

In conclusion, monitoring and improving your reaction speed is not only a way to measure physical health but also a key indicator of brain function and overall wellness. By staying active, both mentally and physically, you can help preserve quick responses and reduce the risk of age-related health issues.