How to Get a Grip on Better Health
For decades, handgrip strength (HGS), measured on a dynamometer, not a handshake, has been used as a proxy for overall strength. It is considered a “strong predictor of general health status, overall morbidities, all-cause mortality, and exceptional[longevity.]” Since we lose muscle mass and strength as we age, HGS has been used to identify the rate of such losses and how it relates to physical decline.
Interestingly, HGS also correlates with knee extension (quadriceps) strength and therefore “predicts mobility and balance disorders, fracture risk, [the performance of] activities of daily living” and even decreased engagement in social and leisure activities. In other words, HGS is a good marker of health and fitness.
Some Finnish researchers evaluated the polygenic risk scores (PRS) for HGS to see if they predicted muscle strength, functional capacity and disability outcomes. Using HGS data originally collected between 2006 and 2010 on 429 women from their Finnish Twin Study on Aging, they tested the strength of the quadriceps and calf muscles, the Timed Get-Up-and-Go, and activities of daily living scores more recently. They also created the PRS in light of modern genetics testing.
They found that the PRS HGS predicts variation in the HGS and the lower body suggesting that the “genetic inheritance of muscle strength could be a noteworthy predictor of functional capacity and further disabilities.”
In sum, “Knowledge about genetic susceptibility could be used to improve personalized risk prediction.”
MSSE Nov. 2022
Does a Personalized Exercise RX Really Work?
As with many advances in medicine, with a drive to personalize treatment according to one’s genetic contribution to a particular cancer, exercise prescription is starting to aim for precision. To the extent that a generic exercise prescription, e.g. walk at this speed for this distance to accomplish this result, is supposed to work for all, it’s a demotivator when it doesn’t work for you. Why some folks derive a benefit from a specific exercise program while others do not is the question a group of researchers from Canada attempted to answer.
Based on 3 randomized controlled trials conducted in their lab, they compared the individual results to exercise programs designed to determine (1) the effects of a diet- or exercise-induced weight loss and exercise without weight loss on subcutaneous fat, visceral fat, and insulin sensitivity in overweight/obese people; (2) the separate effects of exercise amount and intensity on abdominal obesity and glucose tolerance in middle-age abdominally obese subjects; (3) the combined effects of resistance and aerobic exercise compared with either modality alone on risk facts for disease and disability in sedentary older people with abdominal obesity.
Ultimately what they found was that “individual variability in response to a given dose of exercise can be …misguided…[and that] few individuals achieved improvements in commonly measured cardiometabolic risk factors directly attributable to exercise levels” as expected.
Basically, this review of their own studies suggests that “practitioners use caution when attributing benefit or variability” to the exercise prescriptions they write for individuals. After all, we’re all just a study of one.
MSSE Nov. 2022