Adults displaying slow reaction time need to sit up and think about it seriously as this means reduction in life span, says a research published in journal PLOS ONE.
After going through data of over 5,000 participants aged 20-59 year, researchers from UCL and the University of Edinburgh concluded that those who were slower had 25 percent more chance of dying in next 15 years, compared to those who were of average speed.
The researchers studied reaction time of the participants to find out about the sharpness of the central nervous system and the basic mental skills.
Experts also said lack of alertness was as dangerous as smoking.
Lead researcher Gareth Hagger-Johnson, of UCL, said, "Our research shows that a simple test of reaction time in adulthood can predict survival independently of age, sex, ethnic group and socio-economic background.
"It is just one risk factor but it is one we don't normally think about. We think about smoking, we think about cholesterol, we don't think about reaction time," he added.
He said that the speed at which the brain responds may be a reflection of the state of the body. People should try to understand other illness and diseases that the slow reaction might be pointing to. Such persons should see a doctor in order to understand the underlying problems in the body. It could be some deterioration in brain or nervous system, experts said.