Cardiovascular disease remains the leading cause of death worldwide for the last 15 years and running .
Over the years, there have been numerous studies tracking the causes of this devastating health condition globally. In 2019, after decades of research, we’re starting to understand the causes for the disease — smoking , diabetes and high-sugar diets , and sedentary lifestyles .
Recently, the focus has shifted from looking exclusively at what causes heart disease, to what prevents heart disease (including heart attack and stroke).
Studies have repeatedly shown that one of the most reliable markers for lowered cardiovascular disease risk is something called cardiorespiratory fitness (CRF).
For this article I’ve decided to look at the role CRF testing plays in preventing cardiovascular disease.
I’ll also discuss how you can take measurements yourself to assess your CRF, and how these measurements can be used to predict your risk of developing cardiovascular disease later in life.
I hope you find this information helpful! Read on.
A Primer on Cardiovascular Disease
The primary purpose of the cardiovascular system is to allow the movement of blood around the body.
Without the cardiovascular system, our muscles and internal organs have no way of getting the oxygen and nutrients they need to function. The movement of blood around the body is also critically important for removing toxic compounds in and around the cells.
If blood stops flowing to an area of the body for even just a few minutes, it can result in oxygen and nutrient starvation, a buildup of toxic metabolites, and irreversible damage and cell death (necrosis).
If blood stops flowing in the brain, we have a stroke.
If blood stops flowing in the heart, we have a heart attack.
Chinese Medicine: What is Qi?
In Chinese Medicine, qi can really be thought of like oxygen. So the blood carries ‘qi’ to the entire body. Deficiency of either red blood or life giving oxygen (qi) will create weakness and/or stagnation is specific organ or tissue. TCM views the heart organ as the Emperor b/c it rules the blood.
What Causes Cardiovascular Disease?
Cardiovascular disease is an umbrella term for a wide range of conditions ranging from atherosclerosis (inflammation and hardening of the arteries), coronary artery disease (narrowing of the arteries feeding the heart), and stroke (blockage of the arteries feeding the brain).
There are many causes for cardiovascular disease including:
- Lack of exercise
- High trans-fat diets
- Sleeping disorders
- Viral infections
- Genetic predisposition
- Toxic exposure
Aside from avoiding the activities listed above, one of the best ways to reduce your chances of developing cardiovascular disease is exercise.
Using a metric known as cardiorespiratory fitness (CRF), we have a way of measuring the health of our cardiovascular system to better assess our risk of heart attack or stroke.
Here’s how it works. ..
The Relationship Between Exercise & Cardiovascular Health
Some reports suggest that as many as 250,000 people die each year under circumstances that can be attributed to a lack of regular physical exercise .
The relationship between the exercise and cardiovascular health is hard to argue — there have been hundreds of clinical studies on the subject solidifying the connection.
Here are some of the ways exercise impacts cardio health.
1. Exercise & The Heart Muscle
The oxygen and nutrient demands of the body fluctuate on a near constant basis.
While we’re resting, our demand for oxygen and nutrients is relatively low — the heart will beat at an average of 60-100 beats per minute.
As soon as we stand up and start exercising, the demands for these nutrients begins to increase as the muscles require more oxygen/nutrients and toxic metabolic byproducts begin accumulating outside the muscle cells.
The heart responds by beating harder and faster than before — forcing blood around the body faster and at higher pressures.
The more we exercise, the more efficient our heart becomes at keeping up with the energy demands of the body. Just like any other muscle, the more often we push the heart to its limits, the stronger it becomes.
High-level athletes that have spent time conditioning their cardiovascular system with exercise tend to have much lower resting heart rates on average (often below 50 beats per minute). A strong heart doesn’t need to work as hard to meet the demands of the body.
2. Exercise & The Arterial System
Exercise doesn’t just strengthen the heart muscle — it strengthens all of our arteries and blood vessels as well.
The heart uses the arterial system like the plumbing in a building to move blood around to different parts of the body. The arterial walls are elastic and flexible — expanding under the pressure produced by the heart as it beats. This is why we can feel our pulse with our fingers. What we’re feeling is actually our arterial walls expanding as blood is pumped through the system under pressure.
This flexibility is incredibly important — if the walls of our arteries become too rigid, a condition known as atherosclerosis (our risk of heart attack and stroke) increases significantly.
Regular endurance exercise has been shown to improve the flexibility of the arterial system — resulting in a reduced chance of developing serious cardiovascular disease later in life .
Measuring Cardiorespiratory Fitness to Determine Cardiovascular Health
Whether you look at a lack of exercise as being a leading cause of heart disease or exercise as a way to reduce cardiovascular risk — the result is the same.
Expert panels including the Centers for Disease Control and Prevention (CDC), American College of Sports Medicine (ACSM), the American Heart Association (AHA), and US Surgeon General’s Report on Physical Activity and Health (1996), have all reported that physically fit individuals have a lower incidence of cardiovascular disease .
In those that do have cardiovascular disease, the physically fit groups tend to have less severe symptoms overall — leading to a higher likelihood of surviving the incident.
In order to optimize exercise routines that are aimed at reducing the chances of developing cardiovascular disease, a number of useful metrics have been developed to quantify cardiorespiratory fitness (CRF)
We’ll go over our top three metrics in detail in the next section.
Recent trends in cardiovascular health metrics are estimated to reduce coronary heart disease deaths by as much as 30% between 2010 and 2020 .
How is Cardiorespiratory Fitness Measured?
There are a number of ways to assess the health of the cardiovascular system — electrocardiograms measure electrical activity, blood tests assess atherosclerosis, and angiograms explore the health of the coronary arteries feeding the heart muscle.
But how do we assess the general health of the heart using something as subjective as exercise?
The answer is in a metric known as cardiorespiratory fitness (CRF).
This measurement is becoming an increasingly popular tool for assessing the risk of heart disease and stroke. These tests are conducted through physical activity assessments and exercise tolerance testing.
Exercise tolerance is a measurement of the body’s capacity for various forms of exercise. It essentially refers to how much exercise the body can tolerate.
In the past, physical activity assessments were made by self-reported patient history through health and lifestyle questionnaires. Patients were asked to rate their level of fitness on a scale of 1–10.
Unfortunately, this form of testing is highly inaccurate. Cardiorespiratory fitness scores obtained through self-reported questionnaires rarely match up with practical physical exercise tolerance tests .
Accurate and objective CRF assessments (such as exercise tolerance tests) are much more reliable predictors of cardiovascular disease including both heart attack and stroke .
How to Measure Cardiorespiratory Fitness (CRF)
There are a few ways we can measure cardiorespiratory fitness as a way to gauge risk for cardiovascular disease.
Let’s go over some of the most important ones in closer detail:
1. Push-Up Tolerance Testing
A recently published cohort study followed 1104 men between the ages of 21 and 66 over 10 years to measure the relationship between push-up tolerance testing and risk for cardiovascular disease . The study found that those who could complete more than 40 pushups in a single session had an incredible 96% reduction in cardiovascular disease incidents compared to those who couldn’t complete more than 10 pushups under the same conditions.
This research provides strong evidence that push-up tolerance testing can be an effective measure of cardiorespiratory fitness to assess the risk of cardiovascular disease.
How to Test Push-Up Tolerance
- Set a metronome app on your phone to 80 beats per minute
- Do one pushup for every beat until failure or until you miss three beats in a row
- Count the number of pushups you successfully completed
2. Heart Rate Variability
Heart rate variability (HRV) is another metric of cardiovascular health rising to the forefront of cardiovascular disease risk assessment.
HRV is a measurement of the vagus nerve — responsible for controlling the changes in heart rate.
Lower physical activity is associated with poor vagus nerve tone, higher resting heart rate, and increased risk of cardiovascular disease .
The heart is always adapting to changes in the bodies demands — at one moment it might contract once every 1.5 seconds while at other times, beating every 0.8 seconds.
This rate of change is defined as heart rate variability — if the heart is beating at a constant rate, HRV is low. Having a low HRV score is a strong indicator of good cardiovascular health because it shows that the heart muscle is able to handle changes in oxygen and nutrient demands during exercise as well as normal physical activity (such as walking up a flight of stairs).
If the heart is frequently changing its rate as it tries to meet the demands of the body, HRV is considered high — indicating an increased risk of developing cardiovascular disease later in life.
Conditions like atrial fibrillation, and anxiety disorders may also correlate with high HRV scores so it’s equally important to work on the health of the nervous system when managing a high HRV score.
How to Measure HRV
- Purchase a heart monitor that supports heart rate variability testing
- Using an app on your phone, take measurements of HRV first thing upon rising, and throughout the day
- Take these measurements daily over the course of a few weeks to track progress
3. Professional Exercise Stress Testing
Medical professionals can perform what’s called an exercise stress test using tools such as electrocardiograms (ECGs), blood pressure sensors, and pulse oximetry testers. Patients are hooked up to these tools while performing “graded” exercises using a treadmill.
The test begins at a low pace on the treadmill, which is gradually increased to higher intensities.
As the test is performed, heart rhythm activity, blood pressure, and blood oxygenation status are measured. One of the key metrics from this type of study is the maximum heart rate — providing direct insight into the capacity of the heart.
Lower maximum heart rates have the highest risk of death from cardiovascular disease including both stroke and heart attacks .
With this test, a doctor can monitor the capacity of the heart under the stress of exercise.
One study followed 6213 men performing these exercise stress tests in a hospital setting. The researchers in this study concluded that “exercise capacity is a more powerful predictor of mortality among men than other established risk factors for cardiovascular disease” .
The Key Takeaways
The cardiovascular system is one of our most vital systems in the body. Failure of the cardiovascular system due to heart attack and stroke have been the leading cause of death around the world for the last 15 years and running.
Cardiorespiratory fitness scores are becoming the mainstay for assessing cardiovascular risk due to the profound benefits exercise has on this system as a whole.
People with higher exercise tolerance scores have been shown to have better vagus nerve tone, lower resting heart rate, and both a lower severity and frequency of cardiovascular disease than those with low CRF scores.
Using a combination of the tests outlined above, we can quickly and accurately measure our risk of developing cardiovascular disease later in life.
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