What do you do when someone calls out, "Think fast!"? How likely are you to react in time to catch whatever's thrown your way? Your reflexes and reaction time influence just about every aspect of your life. They can cause you to pull away from something hot or painful, and they prompt you to move quickly to avoid a sudden obstacle in your path.

Some people seem to have naturally quick reflexes, which are, in part, influenced by their genetics. If you're curious about whether or not your genetics might impact your reflexes and reaction speed, AncestryDNA^® + Traits test results can reveal any likely connections.

What Are Reflex Actions and Reaction Times?

Reflex actions create instant reactions to set stimuli. They're automatic, like kicking when a doctor strikes your knee with a reflex hammer. Different types of reflexes can cause you to cough, salivate, or even sneeze when exposed to bright lights.

Reaction time refers to how quickly you respond to a stimulus. It's the time between a stimulus triggering your nerves, the nerves sending the impulse to the brain, and the brain sending a response back so your body responds.

Both reflex actions and reaction times play an important role in everyday life. You react to traffic as you drive, switching from the accelerator to the brake when the light turns red. If your hand touches something hot, you reflexively react by pulling away before your brain has processed the temperature, or when you trip, you throw your hands out to break your fall. Ultimately, reflexes and the associated reaction times shape how you respond to your surroundings.

Reflexes, in part, help determine reaction time. Some people tend to have faster reflex actions than others. However, reaction time can be improved through repeated practice. That's why you see athletes running basic skills drills. Through repetition of movements, they become easier and quicker until they're practically reflexive.

Other factors and traits can influence reflex actions and reaction times. Your physical agility, ability to balance, and hand-eye coordination can all impact your response to stimuli.

How Genetics Influence Reaction Time

Interested in how genes influence reaction time, Ancestry^® scientists asked over 234,000 people, "How quick are your reflexes?" By comparing their answers to their genetic profiles, the scientists identified over 450 DNA markers related to reflexes.

With that information, the team calculated a polygenic risk score (PRS), which is used to predict your likelihood of having quick reflexes based on your unique combination of genes. Ancestry scientists found that non-genetic or environmental factors appear to have the greatest influence on reflex or reaction time. Genetic variation only explained about 5% of the differences we see in reflex time.

What Else Do Scientists Say About Reaction Time?

Age has a significant impact on reaction time, but there is no scientific consensus as to the reason why. Research in the 1970s suggested that older individuals’ concern over accuracy slowed their reaction times. More recent findings, from 2022, suggest that slower response times in the elderly may actually be due to changes in how they process stimuli and prepare their movements.

Temporary factors, such as sleep deprivation, can also slow reaction time. This was demonstrated by a small study of 21 anaesthesiologists who had notably slower reaction times after completing night call duty.

Lifestyle factors, such as playing a sport, can also impact reaction times. Researchers looked at 67 students, aged 10-14, and compared the effect of sport and video games on their reaction time. They found that the children who regularly engaged in physical activities had quicker reaction times than those who only played video games. Once gamers move into the field of competitive esports, however, they were found to have similar quick reaction times as physical athletes, particularly with hand-eye coordination, compared with their noncompetitive peers.

Interesting Facts About Reaction Time

Despite the natural decrease in reaction times that occur through the ageing process, middle-aged and older adults may be able to improve their reaction times by engaging in specific types of activities. For example, those who engage regularly in moderate physical activities like tennis or dancing, as well as more strenuous activities like swimming or jogging, are more likely to see better reaction times than those who participate in less-demanding activities like golf, yoga, or Tai Chi.

Other activities that can be beneficial in delaying the slowdown of reaction time include participating in action-oriented and brain-training video games. Likewise, adventure-oriented games may help to improve reaction times more than puzzle-type computer games.

Ready to delve into what your genetic makeup suggests about your reaction time? When you take an AncestryDNA^® + Traits test, you learn more about your genetic affinity towards quick reflexes and other related traits. If you have an Ancestry^® membership and have already taken a test, then your results are now ready to review.

 

References

"A Quick Look at Reflexes. University of Rochester Medical Center. Accessed July 2, 2024. https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTypeID=1&ContentID=562.

Jain, Aditya, et al. "A comparative study of visual and auditory reaction times on the basis of gender and physical activity levels of medical first year students." International Journal of Applied & Basic Medical Research. May-August 2015. doi:10.4103/2229-516X.157168.

Klasnja, Aleksandar, et al. "The Effects of Regular Physical Activity and Playing Video Games on Reaction Time in Adolescents." International Journal of Environmental Research and Public Health. July 29, 2022. doi:10.3390/ijerph19159278.

Liu, Yujie, et al. "The effect of different types of physical activity on cognitive reaction time in older adults in China." Frontiers in Public Health. November 24, 2022, doi:10.3389/fpubh.2022.1051308.

Luu, Ahn, et al. "Reaction Times for Esport Competitors and Traditional Physical Athletes are Faster than Noncompetitive Peers." Ohio Northern University. April 2021. https://doi.org/10.18061/ojs.v121i2.7677.

Nathan, Peter W. , Lentz, Thomas L. , et al. "Reflex action." Encyclopedia Britannica. April 22, 2024. https://www.britannica.com/science/human-nervous-system/Reflex-actions.

Pallavicini, Federica, et al. "Video Games for Well-Being: A Systematic Review on the Application of Computer Games for Cognitive and Emotional Training in the Adult Population." Frontiers in Psychology. November 7, 2018. doi:10.3389/fpsyg.2018.02127

"Reaction Time." Florida Institute for Human & Machine Cognition. Accessed July 2, 2024. https://www.ihmc.us/teacher-resources/reaction-time/.

Saadat, Haleh, et al. "Effects of partial sleep deprivation on reaction time in anesthesiologists." Pediatric Anesthesia. November 30, 2016. https://doi.org/10.1111/pan.13035.

Zelinski, Elizabeth M, and Ricardo Reyes. "Cognitive benefits of computer games for older adults." Gerontechnology. Autumn 2009. doi:10.4017/gt.2009.08.04.004.00.

Ziv, Gal, Ronnie Lidor, Oron Levin. "Reaction time and working memory in middle-aged gamers and non-gamers panel." Acta Psychologica. August 2022. https://doi.org/10.1016/j.actpsy.2022.103666.