Can grip strength be used to predict mortality?
Traditionally, workplace physiotherapists have used grip strength for a range of reasons, including as a measure of a worker’s recovery from an upper limb injury, during pre-employment screening, and more recently as part of proactive health screening.
But can grip strength even predict mortality?
Recent research has shown that grip strength is, in fact, a powerful predictor of mortality from all causes, which includes things such as cardiovascular disease, pneumonia and cancer. Specifically, it is the association between the decline in grip strength when compared to the normal healthy population.
What is grip strength?
Grip strength is a test of the compressive force each hand can deliver. A grip dynamometer is a tool that is used to read the maximum force delivered during a single squeeze of each hand. Grip strength testing is a simple, quick, non-invasive, and cost effective method.
The average healthy caucasian male has a grip strength of 50kg while women have about 40kg. The researchers tend to think your grip strength can be seen as a sum of the physical demands in your life.
How are grip strength values used?
According to one study, for every 5kg of reduced strength there was in increase to the risk of death in a given year by 16% when compared to the healthy population. Low grip strength also had a positive association with chronic and multiple disease states in the study participants. The predictive strength of measuring grip was so powerful that it was better than the predictive value of blood pressure screening. Both tests can be easily combined as an excellent method of checking general health.
Causation vs Correlation.
While the findings are very interesting, it is worthy to note that grip strength has only been correlated to increased risk of mortality. That is, rather than directly causing increased death rates it is only associated with it.
Further study is required.
Researchers mentioned in the studies that further work is required to find out if improving grip strength exercises will decrease mortality risk or if it is the overall fitness that will also improve grip strength. It appears that muscle mass is not as important as the muscle strength in predicting mortality.
What does this mean for workplace health?
Grip strength testing will continue to be vital for measuring upper limb function and recovery. It is a quick, simple and very useful outcome measure to track the improvements from week-to-week.
Employ Health also routinely use grip strength to assist in identifying suitable employees for manual jobs. Ideally, this occurs during pre-employment screening before the candidate has even touched any equipment. The scores are then compared to the inherent requirements for each job type. Screening like this has greatly reduced insurance premiums that our partners pay to cover the cost of injuries.
Employ Health are now using grip strength dynamometers for pro-active health screening to identify employees who are at risk of multiple health issues. This information is then used to devise targeted methods of improvement.
The take home message
Monitoring your employees' grip strength can provide a snap shot of the overall health of your workforce. Combine it with blood pressure for quick and valuable information.
While grip strength is an excellent overall snapshot of health, you are not likely to add years to your life by spending hours punishing a stress ball.
Be nice, a firm handshake is enough, you don’t need to show everyone how long you will live.
References:
Grip Strength, Body Composition and Mortality. Cooper et al, International journal of epidemiology 36, 2007 pages 228 -235
Strength, But Not Muscle Mass, is Associated With Mortality In The Health, Ageing And Body Composition Study Cohort. Goodpaster et al, The journal of Gerontology 71, 2016 pages 72-77
Hand Grip Dynamometry Predicts Future Outcomes In Ageing Adults. Bohannon, Richard W. PT EdD. Journal of Geriatric Physical Therapy 31, 2008 pg 3-10