Health Hack #54 - The Heart is an Engine
|Is the Heart a Muscle?|
As often as possible, I visit our local farmer’s market on Saturday mornings. In the spirit of taking a holistic nose-to-tail approach towards eating animal foods, I’ve been ordering exotic cuts in advance, namely organ meats.
About a year ago, one of my first forays into some of the harder to find organs was a lamb kidney. There are plenty of recipes for cooking kidney, most of which seek to obscure the true kidney flavor via a blend of a variety of flavors, typically by way of a stew-style dish with onions, or often in the form of a blended pate.
It’s hard to believe that our ancestors, who discovered the nourishing quality of organ meats some 2.5 million years ago, had these crafty techniques at their disposal. In the name of primal thinking, I figured I’d adulterate it as little as possible, since if they could handle the straightforward flavor, then I could too. After all, it’s not as though organ meats played too far a distant role in our food culture for our taste buds to have evolved away from tolerating them. And for something so nutrient dense, so vital towards the growth of our brains that it helped compel our most recent leap in evolution to modern day homosapien, it seemed natural to honor and respect it’s natural flavors. (The discovery of organ meats and animal meats and their overwhelming nutrient density in comparison to plant foods in general led to a marked increase in nutrient funneling to our high energy-demanding brains which, over many many centuries, brought about a new form of human.)
I sautéed the kidney quickly in a bit of grass-fed butter with a touch of salt and pepper. The first bite was memorable, as it was the worst tasting thing I’d ever experienced. I described it to a friend as biting into a squishy blob that held the flavor profile of the pungent aroma of a dirty horse stable. I gave him a sample a day later, and he agreed. We both wound up giving all but our first bite’s to our dogs, who had no qualms about it’s flavor.
Soon thereafter I’d cooked up a grass-fed lamb heart, with much greater success. As simply prepared as the kidney, with a bit more seasoning for safe measure. Had I been told I was actually eating a tough cut of traditional steak, I wouldn’t have been surprised. The texture and flavor was reminiscent of grilled (but low quality) sirloin, albeit the meat had a much more distinct brownish color, once cooked.
The following weekend I returned to my standard farmer’s market, eager to chat with owner (I have all the respect in the world for the farm, and for most Philadelphians or surrounding suburbanites, they likely have weekly outposts within reach; check them out here) about my experience. “So the heart was very good, and I didn’t have to do much to it. But the kidney was out of this world disgusting. Why are they so different? What do I have to do to the kidney to make it more tolerable?” His response completely threw me. “Well the heart’s a muscle. So it’s going to taste and feel much like the traditional muscle meat cuts you’re used to. Whereas the kidney is as full-fledged an organ as you can get.” Huh. I’d never thought of the heart as being a muscle.
|The Heart is an Engine|
In general, the heart has a lifespan. Assuming it’s genetically normal, the average heart should have somewhere between three to four billion beats over the course of a lifetime. We can screw this up by applying undue stress on the heart, via any number of ways. A sedentary lifestyle marked by a lack of exercise, a high inflammatory diet, smoking, poor sleep habits, etc. Basically anything that would be classified as toxic for our health is likely to reduce the pre-ordained number of beats our hearts are capable of in the course of a lifetime.
In the same way that we can watch the longevity of the heart suffer due to excess stress, we can actually employ ways to improve its health, and if not grow upon that lifetime beat range, then certainly approach the higher limits of the range potential.
What is the appropriate way to train the heart? Many of us associate cardio exercises with heart health, which is intuitive: cardiovascular health. But is there all there is to it? Just cardio, if we want to improve heart health? And what about dosage? As it turns out, it’s all about diversification. And then, it’s all about dosage. Sound familiar? The right amount of the proper variety of food is the simplest methodology for managing one’s diet.
Luckily, most forms of exercise work this muscular organ pretty directly. Whether we’re lifting heavy weight, sprinting up a hill, or breathing deeply on our mats, we’re applying a hormetic stressor on the heart. We strain it such that it exercises itself and then rebounds stronger than before.
Metrics for healthier hearts are widespread, but they’re generally viewed by a few overarching considerations. One’s resting heart rate, for starters. That is, the stronger a heart, the less it needs to work when the body is idle, meaning that a lower resting heart rate is generally a goal to strive for. Heart rate variability (aka “HRV”) is another key metric, determined by the variation between beats. Generally speaking, an individual with sound HRV has a certain degree of variability in spacing between heart beats while idling, whereas the same individual endures more consistent time lapses between beats while in fight or flight mode (i.e., during vigorous exercise). This expresses a resilience and a flexibility in the heart’s adaptability towards a variety of circumstances.
As it turns out, almost all exercise benefits the heart if prescribed in the right dose. An analogy formed by Dr. James O’Keefe, a world renowned cardiologist, likens the heart to an engine. In this paradigm, it’s important to break down our goals before committing to a lifelong approach. Using the engine analogy, O’Keefe asks us to consider the high performance racing car. Highly equipped for beastly performance now, but definitely not equipped for the odometer to surpass four digits, let along five or six.
There’s a distinct line to be crossed, particularly for the endurance obsessed and/or the high intensity interval obsessed. Take a not so easily digestible finding, for consideration. The heart health of retired professional cyclists was compared to that of age matched controls. It’s natural for us to assume that the epitome of fit - one capable enough to qualify for the Tour de France, let alone complete the race - combined with the lean physique that the sport of cycling requires, would amount to vascular health that is second to none. As it turns out, the retired cyclists were nearly 7 times more likely to have Atrial fibrillation.
High intensity interval training (aka “HIIT”), known for its fat burning capabilities, happens to create a good amount of oxidative stress. This is natural and even beneficial in small doses, but can become a chronic issue when blown out of proportion to moderate exposures. Incessant HIIT has also shown to stretch the chambers of the heart, potentially leading to the tearing of muscular fibers within it. But when done in proper moderation, it strengthens the musculature of the heart and has shown to both reduce our resting heart rate and dramatically improve our HRV.
There’s obviously a huge difference between riding one’s road bike weekly versus training for the Tour de France. And the same world of difference separates the twice per week heavy HIIT session from the workout regimen of the reigning Crossfit champion.
The first point is that we can overdo things, by misinterpreting the appropriate dosage. But the second point, which hinges on diversification, helps to correct for the dosage concerns. Different forms of exercise train the heart in various ways. If you like to jog, and you love to exercise, but all you do is jog, then it’s likely that your exercise protocol is too narrow-minded. It’s been said that if you’re running more than 15 miles per week then you’re training for something other than your good health. In this scenario your heart is liable to yearn for some other forms of training and possibly less training overall.
Recall the standard lifetime of the heart. Yes, by training we’re in effect working towards lowering our resting heart rate, but if we’re overtraining, then we’re not allowing the heart to rest as long as it would like. Therefore, despite achieving the goals of reducing our resting heart rate and increasing our HRV, we may find that our daily beat expenditure supersedes these benefits. Endurance training in particular runs these risks, as evidenced by the cyclists when studied later in life.
A normal resting heart rate for moderately healthy individuals is somewhere between 60-90 beats per minute. An extremely well trained athlete may earn a score somewhere in the 40’s. Usain Bolt is purported to carry a resting heart rate of 33. But at what cost, we must ask ourselves? And when does the insanely demanding training stop, such that we can change course for the future? Fortunately, the heart is extremely resilient, and it’s rarely too late to have no opportunity at reducing any harmful habits. But we should remain very cognizant of our exercise modalities as we age, especially if we’ve been particularly hard-charging in our 20’s, 30’s, and 40’s.