People with a firm handshake are meant to exude confidence and authority. A recent study suggests a strong handgrip may also be evidence that you are going to live longer. Ortega et al. (1) used data on muscle strength, measured in late adolescence, in over 1 million men, as part of their registration for national conscription in Sweden.
They found that hand grip, along with knee extension and strength predicted likelihood of dying before the age of 45 years. In particular, associations were evident for cardiovascular diseases and suicide. The increased mortality was observed in those with a weak handgrip - below the median - with no survival benefit for increasing strength above this point. Although cardiopulmonary fitness has been known to predict survival in young people, this is the first evidence that simple muscle strength tests are equally predictive. The association with risk of suicide was particularly unexpected.
It remains unclear whether training to increase muscle strength improves your outcome but the authors conclude this should be investigated and encouraged as a preventive strategy.
Muscle strength also appears to be critical to survival in later life. In the 1990s Araujo et al. developed a method to score how easily someone can sit down and stand up from the floor. Everyone starts with a score of 5 and then, if the person is unsteady or needs additional supports, such as leaning on their arms, or rolling over, their score is reduced.
They have now followed up around 2000 people aged over 50 years in whom they had measured this score over the previous decade (2). They find the score effectively predicts the likelihood of mortality. Not surprisingly, the score is closely related to age, so that those over 70 nearly all have a reduced score. Nevertheless, they report that the relation persists even after age-adjustment and propose the score may be a useful clinical test. Individuals with low scores could have targeted advice to improve mobility as, they argue, these people will struggle with activities of daily living.
However, because of the strong dependence on age, it seems likely some definition of ‘age-adjusted’ normality may be required to identify those who will benefit most from targeted advice.