This concept makes sense from the standpoint of looking at muscle mass and body strength - we know that physical fitness does has something to do with health. However, muscle strength alone is not sufficient for a picture of optimal health. So, what does the research say?
A study of 4,654 participants in the UK was performed to determine the association between hand grip strength and cardiac structure and function for an adult population in the United Kingdom. Results showed that hand grip strength was related to cardiovascular magnetic resonance based measures of cardiac structure and function which in turn have shown to be predictive of less cardiac hypertrophy (an abnormal enlargement or thickening of the heart muscle) or cardiac remodeling (alterations in the size, shape, structure and function of the heart). Furthermore, these factors have been shown to be negatively associated with the incidence of cardiovascular disease, implying a relationship between hand grip strength and overall cardiac health.
In a 25-year prospective cohort study (Honolulu Heart Program) Japanese-American men living in Oahu, Hawaii were studied in regard to hand grip strength and functional limitations and disability. Among healthy men aged 45-68 years old, results showed that hand grip strength was uniquely predictive of both functional limitations and disability when re-measured 25 years later. Researchers concluded that the maintenance of good muscle strength in midlife may create a protective effect against disability of old age, in large part by creating a greater safety margin and threshold of disability.
An additional study examined 2,987 59-73 year old men and women to determine the possible connection between hand grip strength and health-related quality of life. Researchers concluded that lower grip strength was associated with negative outcomes in regard to reduced health related quality of life. Results suggested that low hand grip strength may present a link between sarcopenia (loss of muscle mass due to the natural aging process) and generalized frailty. Researchers stated that improvement of muscle mass and strength prior to the onset of chronic disorders would behoove the population and possibly prevent low health related quality of life measures.
One study looked at the association between grip strength and cardiovascular, respiratory and cancer outcomes in addition to all-cause mortality. This prospective cohort study of half a million UK participants showed a strong connection between grip strength and all cause mortality as well as mortality specifically from cardiovascular, respiratory, chronic obstructive pulmonary and cancer diseases. Researchers suggested that adding hand grip strength as a regular screening tool for health may be warranted.
Though it appears that hand grip strength may be a moderate predictor of health, there is far more involved in health outcomes than one screening tool or health measure. Therefore, it would behoove all of us to take into consideration all components of diet and lifestyle and stay away from relying on one test to measure overall health. Maintaining a pattern of dietary excellence, exercising regularly (5-6 times a week), for appropriate durations (45-60 minutes), with adequate intensity, and staying hydrated will round out the approach of overall health a little more and present far greater results.