President Donald Trump’s notable handshakes often manage to find their way into headlines, gaining wide attention. From his interaction with Japan’s former Prime Minister, Shinzo Abe, that prompted an eye-roll from the politician, to the former FBI director, James Comey, who was reportedly pulled in by Trump, who had attempted to hug him.

Trump’s interactions with President Macron particularly cause a stir, with a report claiming that Macron’s knuckles went white as the pair exchanged a handshake at the NATO summit in 2017. Though the awkward handshakes have been criticised, according to research, it seems that the US president is displaying signs of great health.

A study of 140,000 adults in 17 countries found that a weak grip is linked to a higher risk of heart attack and stroke, as well as a better guide to “all-cause mortality” than blood pressure. It is also connected to a string of other health conditions, including osteoporosis, diabetes, rheumatoid arthritis, fall risk, obesity, and cognitive decline. Age-related muscle loss, or sarcopenia, is also tied to a weak grip.

This is why doctors often use grip strength as a quick measure of a patient’s health, including their ability to recover from surgery or live independently. Physiotherapist Sarah Milner. “You don’t need to hook someone up to a machine, you don’t need to look at their muscle mass, you don’t need to check their weight.”

The downside of the test is that it focuses on upper-body strength, which is why patient assessments often combine a grip test with a sit-to-stand test, which gauges lower-body strength, reports The Guardian.

According to Delhi GP Ramit Singh Sambyal, grip strength reliably reflects “total body strength, neuromuscular coordination, and cardiovascular resilience.” He also shared that patients in their 50s with a surprisingly weak grip often report fatigue, slower recovery after minor illnesses, and a higher percentage of body fat. In contrast, those with a stronger grip typically have better functional fitness and recover quickly.

There are plenty of ways to assess grip strength, including squeezing a tennis ball and seeing how long you can hold your tightest grip. However, a formal measurement is done using a device known as a dynamometer.

Samantha Shann, an occupational therapist at Oak Tree Mobility and the World Federation of Occupational Therapists president, said grip strength varies between age and gender. But typically, this is how much force an individual should be able to exert:

• 18 to 25, women 27-31kg, men 46-52kg
• 26 to 35, women 26-30kg, men 44-50kg
• 36 to 45, women 25-29kg, men 42-48kg
• 46 to 60, women 20-28kg, men 35-47kg
• 61 to 75, women 18-26kg, men 30-45kg
• Over 75, women 16-20kg, men 25-40kg

“Everyone’s baseline differs,” says the therapist, who recommends using everyday activities to strengthen grip. “Tasks like cooking, gardening, or carrying laundry all challenge grip in a natural and functional way.

“Structured exercises can be added in when more support is needed, such as a tennis ball squeeze (hold for three seconds, release, and repeat 10 times per hand, daily) or a towel twist (roll a towel and twist it in opposite directions, for one or two minutes a few times a week). I usually tell clients they can expect to notice small improvements in four to six weeks if they’re consistent.”