You probably give a couple of firm handshakes a day. A firm handshake not only helps you make a good first impression, it can also serve as a good indicator of your health. According to a recent study published in the journal The Lancet, the firmness of your hand grip, which measures muscular strength, is better than your blood pressure when it comes to predicting mortality and morbidity.

Typically, hand-grip strength decreases as you age, according to the American Academy of Orthopaedic Surgeons. This makes it more difficult to accomplish routine activities, such as opening a jar or even turning a key. The simple squeeze can become an important diagnostic tool in assessing strength and quality of life. It can be highly predictive of functional limitations and disability years later.

"Grip strength could be an easy and inexpensive test to assess an individual's risk of death and cardiovascular disease," said Dr. Darryl Leong, principal investigator and an assistant professor of medicine of McMaster's Michael G. DeGroote School of Medicine and cardiologist for the hospital, in the press release. "Doctors or other health care professionals can measure grip strength to identify patients with major illnesses such as heart failure or stoke who are at particularly high risk of dying from their illness."

In an effort to measure the prognostic value of grip strength in socioculturally and economically diverse countries, Leong and his colleagues followed about 140,000 adults aged 35 to 70 over a period of four years in 17 countries. They were taking part in the institute's Prospective Urban-Rural Epidemiology (PURE) study. The participants received surveys that elicited self-reported demographics, cardiovascular risk factors, comorbid disorders, education levels, employment status, physical activity levels, tobacco and alcohol use, and dietary patterns. Antropometrics — the measure of physical sizes and shapes in humans — blood pressure, and muscle strength — measured via handgrip dynamometer — were assessed.

The findings revealed for every 5-kilogram (11 pounds) decline in grip strength, there was a one in six increased risk of death from any cause. There was the same 17 percent higher risk of death from either heart disease or stroke, or non-cardiovascular conditions. The correlations with grip strength were not accounted for by differences in age, sex, educational level, and physical activity, among many others.

Grip strength was a strong predictor of cardiovascular mortality and a moderately strong predictor of incident cardiovascular disease for people of diverse economic and sociocultural backgrounds. These findings suggest muscle strength is a risk factor for incident cardiovascular disease and can even predict the risk of death in people who develop either cardiovascular or non-cardiovascular disease. These findings will help the researchers devise a way to improve low muscle strength in patients to increase their life expectancy.

A similar 2014 study published in the journal PLOS ONE found hand grip is related to other markers of aging, such as people’s future mortality, disability, cognitive decline, and the ability to recover from hospital stays. The researchers analyzed over 50 studies from people around the world and of all ages and found a 65-year-old white woman without a completed secondary education had the same handgrip strength as a 69-year-old white woman who had completed her secondary education. Based on their hand-grip strength characteristic, their ages are equivalent and the 65-year-old woman aged four years faster due to lower education attainment. This suggests less-educated people with less access to health care may have weaker handshakes, which is associated with lower life expectancy, higher rates of disease, and faster rates of cognitive decline. In other words, the speed of aging across different population groups can be measured with a simple hand-grip strength test.

Currently, blood pressure is used as a tool to measure the health of patients, especially in regard to cardiovascular disease. It is still used as a good indicator of your overall health, although elevated blood pressure does not indicate a medical condition or risk. However, the idea of a grip strength test being performed at a patient’s annual physical is not only cost-effective but less invasive.

It has yet to be seen whether this link applies to younger adults and whether these interventions can improve physical ability and reduce the risk of an early death. Hand-grip focuses on body strength. You can keep your grip strong by going regular hand exercises like squeezing a tennis or foam ball repetitively.

Sources: Leong DP et al. Prognostic value of grip strength: findings from the Prospective Urban Rural Epidemiology (PURE) study. The Lancet. 2015.

Scherbov S and Sanderson WC. Measuring the Speed of Aging across Population Subgroups. PLOS ONE. 2014.