You can find out a lot about a man by his handshake - about his personality, his feelings towards you, or... his heart health. According to a new Canadian study, a firm handshake is a reliable indicator of good health; they actually want to use handshake tests as initial ways to gauge the risk of heart attack and stroke.
The study analyzed 140,000 patients aged between 35 and 70 in 17 countries, monitoring their health over 4 years. The first thing they noticed was a national variation in grip strength - Swedes have the firmest handshakes, while Pakistanis have the limpest. They then established a baseline; the average grip strength was 300 newtons, the force it takes to lift 30.6 kgs off the ground. Every 50-newton drop below this was associated with a 16 per cent rise in the mortality risk, and in particular, a 17 percent risk of mortality risk associated with heart disease. In other words, the limper your hand shake tends to be, the more likely you are to suffer heart issues.
Does that mean that Swedes for example have much better hearts than Pakistanis? Well, I couldn't find any data to directly back up that idea, but overall stroke rates have declined sharply in Sweden over the past 25 years, as have the dangers associated with strokes. Meanwhile, the Pakistani population has one of the highest risks of coronary heart disease (CHD) in the world. So for those two extremes, statistical data seems to back up this study.
Scientists actually believe that handshakes can be used as inexpensive methods of identifying someone's risk of a heart disease. Of course, this is nowhere near as accurate as an actual test, but it seems to be a very good indicator.
"Doctors or other healthcare professionals can measure grip strength to identify patients with major illnesses such as heart failure who are at particularly high risk of dying from their illness," said Darryl Leong, an assistant professor of medicine at McMaster University in Hamilton, Ontario, who led the investigation.
But the handshakes have to be corrected for several factors, including size, weight, muscular mass and ethnicity. More research is also needed to understand exactly why this correlation happens - it's clearly connected to the blood supply to the hand muscles, but the exact mechanism is still somewhat a mystery.