Research & News RoundUp
Grip strength declines with age – this is an unwelcome change I’ve noticed even in myself, despite a good, consistent resistance training habit through adulthood. Jars that were completely uneventful for me, I need more effort to open, or resorting to using a jar-opening tool. This is in part, what makes me interested in grip strength.
Beyond that, grip strength is an easy surrogate marker for overall health and aging. All in, there is a LOT of research on grip strength associations. It’s simple to measure and track at home or in clinical settings. Read on to find out more including how to use grip strength in clinical practice and what we can realistically impact by working on improving grip strength.
What is grip strength?
There isn’t any great secret to understanding grip strength – it’s exactly what it sounds like – the amount of force you can generate with your hands. It is the exertion needed to grasp an object and is necessary for the daily functional activities of life. We all use this force every day to do things like opening a jar of pickles, carrying grocery bags, or lifting a pan off the stove.
How grip strength connects with health and aging
No surprise, grip strength declines as we age, as early as 45 and is correlated with poor health outcomes. And consistent exercise as we age (also no surprise) is associated with stronger grip, more muscle, and healthier outcomes. The biological age clock that I rely on most in clinic, the Pace of Aging (aka Dunedin PoAm) (which we also use in combination with select other measures in this customized biological age assessment) has grip strength as one of the phenotypic markers in the large datasets used to build their age-predicting model.
Studies across different populations (adolescents, women, men, and older adults) have reported that grip strength is associated with several important health markers and outcomes including muscle loss (sarcopenia), bone density, type II diabetes, cardiovascular disease, stroke, cognitive decline, depression, and even mortality.
Here are some specific studies worth highlighting:
- Bone density: One recent study published in Current Developments in Nutrition found that demographic factors (age and sex) and body composition factors (lumbar BMD and total lean mass) explained 42.3 percent and 35.3 percent of the variance in grip strength, respectively.
- Epigenetic age: Another recent study published in the Journal of Cachexia, Sarcopenia and Muscle showed that grip strength is inversely associated with epigenetic age, including in the Pace of Aging clock, as well as the PhenoAge and GrimAge clocks (they did not use any other clocks in their analysis).
- Metabolic health: Yet another recent study in Diabetes Research and Clinical Practice found that higher handgrip strength correlates with more favorable markers for metabolic syndrome and inflammation including waist circumference, body fat, HDL cholesterol, fasting glucose, fasting insulin, HOMA-IR, triglycerides, systolic blood pressure, and hsCRP.
How to measure grip strength
Grip strength can be measured by a hand-held dynamometer. Several different brands are available.
There has been an effort amongst the scientific community to standardize the process for measuring hand grip strength since results can vary depending on whether the patient is standing or seated, for example. Here is an adaptation of the version used by the American Society of Hand Therapists and Southampton University that I think is useful:
- Device calibration: Dynamometer should be calibrated according to manufacturer’s instructions.
- Preparation: Patient should be comfortably seated with their feet flat on the floor and their arm resting on a flat surface. The shoulder and wrist should be in neutral positions throughout, and the elbow bent at 90 degrees.
- Grip position: The patient should hold the dynamometer in their hand so that the handle is resting comfortably against their palm.
- Grip technique: All four fingers should wrap around the handle, while the thumb remains on the other side. The patient should avoid sudden jerks or movements during the squeeze.
- Measurement: Encourage the patient to squeeze the dynamometer with maximal effort, but without excessive straining, for 3 to 5 seconds: “I want you to squeeze as hard as you can for as long as you can until I say stop.”
- Rest between trials: 1 minute rest between each trial to prevent muscle fatigue.
- Repeat measurements: Conducting 3 squeeze trials for each hand alternately may provide a more accurate overall average measure.
How to interpret grip strength
This evaluation of grip strength performance from 9431 participants in the GenoFit study provides useful normative data and grip strength thresholds (in percentile) in a large adult population. Participants from this data set were aged between 18 and 92 years, and included both men and women.
An important caveat about grip strength training (Don’t believe everything you hear on the Internet!)
Some health enthusiasts have jumped on grip strength training – i.e., building up your grip strength through hand exercises – as a longevity panacea. However, it’s important not to over-interpret, or over-focus on grip strength, just like any other biomarker we use.
The reality is that grip strength training can only provide LOCAL, not systemic, benefits when applied in isolation. Relying on grip strength training alone, while watching TV sitting on the couch, is likely not appreciably reducing diabetes or dementia risk.
However, improving grip strength as part of an overall health improvement strategy, with diet, exercise, and other lifestyle factors, can still add benefit – after all, being able to open food jars, lift grocery bags, and drain hot water from cooking pans safely are all activities that contribute to successful, healthy living. There is some evidence for the utility of grip exercises on hand and upper body strength and are used in sports, injury rehabilitation, and even pain management programs. And if you’re doing resistance training with weights or kettlebells (or carrying your suitcase – without rollers!) you’re already engaged in a pretty serious grip strength activity!
As part of an overall health and longevity strategy, bolstering grip strength makes sense.
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