Heart health: Part II – Heart rate, variability and food

checking for heart rate

Resting heart rate – slower is better

As your heart gets more efficient and stronger – it can pump more blood with each stroke (and, potentially, require less energy to do that).  Eventually, what this leads to is slower resting heart rate.  Remember, the heart rate is a product of the demand for oxygenated blood and your heart’s ability to satisfy that demand.  As this ability improves, the heart doesn’t need to beat as fast.

This is precisely where the benefit of exercise comes in.  Exercise not only strengthens the heart itself and makes it more efficient in accessing oxygen in the blood (by growing more mitochondria) – but it also triggers the growth of new mitochondria (as well as improvement in oxidative capacity of existing mitochondria) at the periphery (i.e. – within the target tissue).  All of that means that tissues in need of oxygen could now use less of it to satisfy the same demand for energy – which means your heart doesn’t need to beat as fast.

What benefits does slower heart rate have?  There may be a couple:

  • Slower heart rate means a bigger “buffer” between current and maximum heart rate to keep up with more demanding situations when the heart needs to beat faster. Remember – the maximum rate is a finite number for everyone – your heart can’t just beat faster and faster in response to the demand – because the heart itself needs oxygen from blood to perform the work. Faster heart rate means higher energy demand for the heart muscle itself – and at some point, the ability to fuel this process by oxygen delivered by the blood will be limited by the supply of that freshly oxygenated blood and the speed at which it is utilized within the aerobic metabolism pathways.  No available energy at any given moment means no ability to contract.  So a slower heart rate potentially means more energy-efficient heart and a higher capacity to increase that rate to address spontaneous demands for blood delivery;
  • As we have already mentioned, muscle contraction requires energy – which comes from oxidation of fat, glucose or ketone bodies. Cellular energy metabolism – while being absolutely essential for life – also generates several chemical and electrical by-products that, in large amounts, can be harmful.  For instance – we have already discussed positive hydrogen ions (H+) generated by muscle contraction that raise the acidity of the cell.  Also, cellular metabolism generates reactive oxygen species that are known to inflict damage to cell’s DNA and cause various disorders.  It follows, then, that less energy required for resting heart rate means less of such by-products – which, by the way, may contribute to the wear and tear and, as a result – the longevity of the heart itself.  Perhaps it is no coincidence that animals with generally slower heart rates live longer?

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Heart health: Part I – Heart Disease and Cardiovascular Health

heart disease prevention

What you need to know about heart disease, rate variability, effect of exercise, nutrition and more

What is the most dreaded disease of the modern world?  Most people would probably say: cancer.  Yet, cancer is by far not the most prevalent cause of death.  That place is actually firmly occupied by ischemic heart disease, according to statistics published by World Health Organization (WHO).

So it makes sense to try to do what you can to prevent being a part of this statistic.  The article below explores a few potential causes of heart disease, discusses risk factors (including some of those that are not well known) and preventive measures (including some unconventional but very effective ones).

What makes your heart beat

On average, your heart pumps about 7,200 liters of blood per day.  In an average lifetime, that equals about 2,628,000 liters (700,000 gallons) or about 2.5 billion contractions.  That’s a massive amount of work!

As with any muscle, to maintain the strength and pace of these contractions, two variables must be present – the constant availability of fuel and proper functioning metabolism that utilizes this fuel to produce electric energy required to contract the muscle.

The heart is generally considered as a substrate omnivore with the capacity to oxidize fatty acids, carbohydrates, ketone bodies, lactate and even amino acids, the preferred substrate being fatty acids.

That said – energy deficit is a key contributor to heart failure.  During high intensity exercise, for instance, the heart uses up to 90% of its oxidative capacity – so it has no excess capacity of energy generation over energy utilization.

Under these circumstances, it is very important that whatever oxidative capacity your heart does have for supplying energy to cover the immediate needs is utilized to the maximum – and that such capacity is increased to provide some buffer for more strenuous activities, should those take place.  Ninety percent of the heart’s energy requirement is met by mitochondrial oxidative phosphorylation, which is finely tuned to energy need on a “pay as you go” basis.  In fact, mitochondria (power plants of the cell) occupy more than 30% of the cardiac muscle cells’ volume.

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Is red meat bad? (Part II – IGF-1, risk of cancer and more)

Is meat bad for you

Let’s continue our discussion that we started in Part I and see if there really is any association between meat and cancer.

It’s different if you already have a pathology

It is often implied that high-protein diet causes damage to your kidneys by “overloading” them with nitrogen by-products of protein digestion (that they naturally metabolise and excrete) – but as a healthy individual, you will have difficulty overconsuming protein, since your body has natural regulatory mechanisms that drive the desire for protein-containing foods.  So you are unlikely to ever eat too much.

But is it correct to say that eating any amount will put a strain on your kidneys?  Should you specifically reduce protein consumption to avoid damaging them?

The answer is – very unlikely.  If you already have a kidney disease – increased protein consumption can definitely contribute to their pathology.  But if you are healthy – you probably don’t have anything to worry about (read this article by Chris Kesser).

Methionine

Meat contains a complex array of several amino acids.  One of these amino acids is methionine – and recent studies have suggested that it’s this specific amino acid that may be responsible for increased oxidative stress and the ultimate link between meat, IGF-1 (see below) and cancer.

If you recall our discussion on organ meats – you will remember that methionine is balanced by glycine – another amino acid contained in large amount in bone broth, gelatin and organ meats – which helps your body metabolize and neutralize potential harmful effects of methionine. What follows is that if you balance your intake of methionine with your intake of glycine (by consuming collagen/gelatin, organ meats, bone broth, etc.) – potential harmful effects of overconsuming muscle meat can be greatly reduced.

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