A new study, published in the journal PLOS ONE, has found that adults who have slow reaction times have a higher risk of an early death.
Reaction time was studied because it reflects how well the central nervous system is working. It also reflects basic mental skills, such as how quickly a person is able to process information.
In a reaction time test, participants have to press a button as soon as they see an image appear on a computer monitor. An example of a test similar to the one used in this study can be found here.
In the new study, researchers analyzed data from more than 5,000 patients in the US aged between 20 and 59. In the early 1990s, the participants underwent a reaction time test, and researchers followed them over the next 15 years to record which participants had died and which survived.
Of the people in the study, 378 (7.4%) had died in the 15-year period. Cross-referencing this data with results from the reaction time test, the researchers found that the participants who logged slower reaction times were 25% more likely to have died.
When analyzing the results, socio-economic background, age, sex and the ethnic group of the participants was taken into account, as well as lifestyle. So the researchers do not think these factors could have biased the results.
What can reaction times tell us about a person's future health?
Although the study found a link between reaction time and when the participants died, the study was not able to determine what causes of death slow reaction was linked to. For example, the researchers did not find a connection between reaction time and and respiratory problems or death from cancer.
"The reasons for the link between slow reaction time and death are not yet known," lead researcher Dr. Gareth Hagger-Johnson told Medical News Today.
"One theory is that slow reaction time might reflect deterioration of other bodily systems, such as the brain and nervous system. Perhaps people who are slower to react are also more unhealthy, or forget to do things which might keep them healthy."
According to Dr. Hagger-Johnson, people who are slower to react may not be good at avoiding hazards or remembering to take medication.
"If this is true," he added, "there might be some unknown 'common cause' of both slow reaction time and physical illness. We are keeping an open mind until more research has been conducted on mechanisms that might explain this result."
Dr. Hagger-Johnson thinks that reaction time could be used to monitor specific aspects of patients' health:
"Reaction time may indicate how well our central nervous and other systems in the body are working. People who are consistently slow to respond to new information may go on to experience problems that increase their risk of early death. In the future, we may be able to use reaction times to monitor health and survival. For now, a healthy lifestyle is the best thing people can do in order to live longer."
Last year, Medical News Today reported on a study that found reaction time could be improved by drinking water.