How Strong Is Your Heart?

First, let’s take a moment to remember that the heart is a muscular organ, which is why exercise strengthens it, whereas for many organs, pushing them to their limits does not improve their performance (think of your liver, kidneys, pancreas, etc, all of which should be given as easy a time of it as reasonably possible, for best performance).

When it comes to our muscles in general, we can be genetically predisposed to stronger or weaker muscles, often manifesting as denser (or less dense) muscle fibers. Which way your genes predispose you can be found by genetic testing (personal genomics).

For reference, see: Genetic Testing: Health Benefits & Methods

Muscle = muscle

Ok, there are many different types of muscle, and within muscles there are different types of muscle fiber. But there are some things that are true of muscle in general, and for these purposes, “muscle = muscle”.

One of them, it seems, is that if we have a genetic predisposition for stronger muscles, then this also holds true for our heart.

Most recently, a Finnish team of researchers, Dr. Katja Waller et al., looked at many (n=8,815) people’s data, and most specifically, the association between the polygenic score for handgrip strength, on cardiovascular disease mortality and all-cause mortality.

What they found is that those with a genetic predisposition for higher muscle strength had a lower risk of cardiovascular death, regardless of their physical activity or lifestyle habits. This association remained even after accounting for factors like smoking, alcohol use, and BMI.

You may be thinking: but what if the predisposed-to-be-stronger people were simply more active as a result?

That’s a fair question, because indeed people with genetic predispositions to be good at something (in this case, physical activity) may indeed do more of it.

However, the data showed that genetically stronger individuals were not, on average, any more active than others.

You can read the paper in full, here:

Genetic Liability to Higher Muscle Strength Associates With a Lower Risk of Cardiovascular Disease Mortality in Men Irrespective of Leisure‐Time Physical Activity in Adulthood: A Longitudinal Cohort Study

Wait, what’s that about “in men”?

So, the study participants were 53% women, however, the association which was strong for men, was not so strong for women. The researchers hypothesized that this may have had to do with differing biological and environmental influences, especially the potentially confounding effects of the cardioprotective role of estrogen premenopause, and of course postmenopause in those taking menopausal hormone replacement therapy—something the researchers didn’t control for.

However, previous work by another (well, some team members were the same) Finnish team of researchers, Dr. Kaisa Koivunen et al., found it was indeed predictive for women as well as men, and that the impact was significant but modest.

In case you’re wondering how the impact can be described simultaneously as “significant” and “modest”…

Since “significantly” tends to get used colloquially to mean “a lot”, let’s recap that in science, “significant” means “the probability of getting these results randomly is less than 0.05”. It does not mean that the difference is necessarily large—merely that it is improbable by random chance, and therefore it suggests that one thing is associated with another (specifically, at least one input variable is affecting at least one output variable; in this case, genetic predisposition to greater muscular strength predicts lower cardiovascular disease mortality).

You can read this paper in full, here:

Genome-Wide Polygenic Score for Muscle Strength Predicts Risk for Common Diseases and Lifespan: A Prospective Cohort Study

And another one, this time still with Dr. Elina Sillanpää who contributed in the other two studies also, to keep it company:

Associations of polygenic inheritance of physical activity with aerobic fitness, cardiometabolic risk factors and diseases: the HUNT study

So, how do I make use of this kind of information?

Firstly, know that your genetic predispositions of many kinds (not just this one) can not only predict your health risks, but also highlight what areas of your health you might need to pay particular attention to, as well as in some cases, what treatments are more or less likely to work well for you—which in turn, is information that can making life-changing differences to your treatment plan when one day something comes up (and rest assured, unless you die early by some accident/incident, something will come up at some point).

Next, check out: Do You Have A Personalized Health Plan? (Here’s How)

…for how to proceed 😎

Take care!