From the limp noodle to the bone crusher, a person’s handshake can say a lot about who they are. Research has suggested a weak grip is associated with poor health and can serve as a clinical marker for obesity and even death. A “gripping” new study now suggests that the strength of one’s handshake could also indicate intelligence.
Researchers set out to examine the strength of a handshake and how it relates to cognition skills in more than 475,000 people in the UK – specifically those with schizophrenia – by measuring memory, reaction time, and reasoning. Data collected between 2007 and 2010 from the nationwide health study UK Biobank was analyzed before testing respondents in personal interviews, physical health assessments, and a touch-screen questionnaire. Using a hydraulic hand dynamometer, researchers then measured participants’ handshakes. They found a higher grip strength significantly and positively related to better task performance in people with and without schizophrenia even when accounting for age, gender, weight, education, and geographic region.
“This population-scale study confirms, in a large sample, the significant correlation between grip strength and multiple cognitive domains in the general population,” the authors wrote in their study, which is published in Schizophrenia Bulletin.
It’s part of a growing body of work that shows just how powerful a handshake can be. A 2012 study found the simple greeting increases a positive feeling in an interaction between two people and diminishes the impact of a negative impression. Despite its small sample size, another study by the American Psychological Association found a strong correlation between a firm handshake – defined by its strength, vigor, duration, eye contact, and completeness of grip – and a favorable first impression.
Because a handshake can also be associated with physical health and strength, the authors of the new study say understanding handgrip could serve as a potential marker of cognitive dysfunction.
A limitation of the study is that some of the cognitive tasks included fewer participants than others. In these instances, the relationship between grip strength and cognition fell short of statistical significance but other tasks with larger sample sizes made up for this. In addition, the authors say a lack of information on schizophrenia-specific factors, such as real-world functioning of participants, could have impacted the link between the two.
The study authors say further research is required to fully understand these relationships and the implications of grip strength for real-world functioning in psychiatric populations. Future studies to look at whether muscle-strengthening interventions can help to enhance cognition, particularly in the early stages of illness, are necessary.