THE CARDIOVASCULAR CONUNDRUM: How much “Cardio” is enough?
Clifford Thornton-Ramos
Medical Technology and Education Marketing Consultant & Freelance Journalist (Healthcare - Models & Policy, Biotech, Medical Devices, Innovation, Career Coaching, Training Instruction, Health & Fitness, and Wellness)
You may be reevaluating your existing exercise and fitness program or working to design a new one and in doing so asking, “ok, now how much cardio do I need?” Well, that’s a great and important question. “Cardio” or cardiovascular exercise refers to exercise that essentially “works out your heart”. In reality, it also “exercises” your lungs, arteries, and the rest of the cardiovascular system.
Yes, for most young people and even into middle-ages, our heart seems to work just fine and pumps our blood while we work, while we grow and raise families [all types of family structures], while we dance, jump, and do whatever it is you usually do. Most of us don’t really think about it. But unfortunately, as we spend more years on this Earth and age, our heart, lungs and arteries lose some of their “spring”. The heart tissues and fibers can literally become stiffer or “less compliant” [which can affect one’s diastolic function, that is, how the heart fills with blood] - https://www.dhirubhai.net/pulse/whats-big-deal-diastolic-dysfunction-heres-what-clifford-thornton/ ]; same can happen to your arteries, especially if your genetics and lifestyle [smoking, obesity, sedentary lifestyle, fatty diet] predispose you to atherosclerotic disease ?[https://my.clevelandclinic.org/health/diseases/16753-atherosclerosis-arterial-disease].
Not to cloud your day, but your lungs or lung function can also decline to some degree [based on various factors such as if you exercise regularly, if you smoke, if you have lung disease, genetics, environmental factors, etc.] as you advance in age. This decrease typically begins around age 35.
More specifically, the diaphragm, a muscle that assists with breathing, can gradually become weaker. Furthermore, lung tissue that supports your airways by keeping them open, can lose elasticity [same for the heart muscle and arterial walls], and the result here is that your airways can literally become a bit smaller [negatively affecting the blood-gas exchange].
The good news is that, just as you can minimize the affects of aging on heart function, the same is true for lung function, namely through regular cardiovascular exercise. So, what are the mechanisms behind this?
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“When you are physically active, your heart and lungs work harder to supply the additional oxygen your muscles demand. Just like regular exercise makes your muscles stronger, it also makes your lungs and heart stronger. As your physical fitness improves, your body becomes more efficient at getting oxygen into the bloodstream and transporting it to the working muscles. That's one of the reasons that you are less likely to become short of breath during exercise over time.
Some types of exercise can also strengthen the muscles of the neck and chest, including the diaphragm and muscles between the ribs that work together to power inhaling and exhaling.”
Source:
Exercise and Lung Health
American Lung Association
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The takeaway here is that cardiovascular exercise puts stress [a good type of stress] on the heart and lungs, as well as the surrounding muscles, and at the end of the day, this makes them both stronger and more efficient. In turn, by keeping them strong and efficient, you are combating the aforementioned aging effects on them.
The below is a more comprehensive review of the benefits of regular cardiovascular exercise.
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CLINICAL BENEFITS OF PERFORMING REGULAR CARDIO:
·???????? Lowered resting heart rate (HR); over the course of your life, this can extend the life of your heart and hence your life given that less heart beats in a resting state each hour, day, week, etc. of your life means less wear and tear on your heart. This is accomplished through each heartbeat being more efficient and pumping a greater volume of blood each heartbeat [also known as the stroke volume (SV)], hence less heart contractions are required to keep you going and keep the cells of your body well-oxygenated.
·???????? Cardiovascular exercise has been shown to maintain good diastolic function of your heart [the phase of the heart cycle where the ventricles of your heart fill with blood]; unfortunately, as we age our hearts become stiffer and our ventricles become less receptive or less “compliant” to receiving blood from the atriums of our heart. As a result, our atriums via the “atrial-kick” have to do more work to in a sense complete the heart filling prior to the ventricles of the heart contracting, which we call systole. Too much strain on the atriums to push blood can lead to both hypertrophy or thickening of the atrium walls and even atrial-fibrillation [“A-fib”], which can lead to an increased risk of a trans-ischemic attack [TIA] or a full-blown stroke. Cardiovascular exercise literally exercises the heart and can help one maintain a good, healthy diastolic function, late into life.
·???????? Helps keep blood pressure within the ideal range
·???????? Helps keep your arteries flexible and supple; also, as we age our arteries become stiffer and less pliable. This is not ideal. Cardiovascular exercise can help significantly slow down and counter this ageing phenomenon by also exercising the arteries as they expand and contract during aerobic exercise.
·???????? Helps keep your cholesterol [HDL and LDL] at the ideal levels
·???????? Improved and maintenance of good cognitive function
·???????? Offers nice glow of your skin
·???????? Improved lung and overall respiratory function [increases your VO2 max [related article: https://www.healthline.com/health/vo2-max ]
·???????? It can possibly save your life in an emergency such as escaping from a fire, running away from an active shooter situation, etc...
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These are some of the most common forms of cardiovascular exercise [certainly not all-inclusive]:
TYPES OF CARDIOVASDCULAR EXERCISE:
Aerobic / Cardiovascular Exercise
·???????? Running or jogging
·???????? Biking [road or trails]
·???????? Swimming [it just so happens that swimming is also strength training and arguably one of the best forms of exercise, that is any kind of exercise]
·???????? Rowing [on the water or rowing machine]
·???????? Aerobic type classes [also good for increasing your flexibility]
·???????? Martial arts [also terrific strength training as well as flexibility training, not to mention the ability to defend yourself if needed]
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Now that we’ve established how age impacts heart and lung function and what you can do about it and why, let’s take a look at just how much of the cardio stuff we should aim for [AKA the “Goldilocks zone”].
So let me get to the million dollar question you’re ready to get answered.
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Just how much cardio is enough or recommended?
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From various, reputable sources [listed below in the bibliography], the general consensus seems to be that we should aim for 150 minutes of cardiovascular exercise each week [each session should ideally be continuous in order to keep your heart rate elevated, maximizing the benefits]. However, for optimal health benefits which I’ve highlighted earlier, we need to fit in 300 minutes of cardiovascular exercise per week. And if you’re willing to up the ante and choose to engage in vigorous cardiovascular exercise, then the magic number you should target is 75 minutes per week. Now you might be asking a good question, “How is vigorous exercise defined?”
If the heart rate monitor shows that you’re working at 70 to 85% of your maximum heart rate then it’s vigorous exercise [To find your maximum heart rate, subtract your age from 220].
With that, we should apply some caution if a good portion or all of our exercise is of the vigorous type. Therefore, we should limit vigorous cardiovascular exercise to 4 to 5 cumulative hours per week, especially for those over 45 years of age. And it would “do a body good” if you take off at least one day per week from vigorous exercise.
If you’d like to dig deeper into this issue, please see below for recommendations on the weekly amount of cardio you should get, from various sources:
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“Get at least 150 minutes of moderate aerobic activity a week. Or get at least 75 minutes of vigorous aerobic activity a week. You also can get an equal combination of moderate and vigorous activity. Aim to spread out this exercise over a few days or more in a week.”
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“For even more health benefits, the guidelines suggest getting 300 minutes a week or more of moderate aerobic activity. Exercising this much may help with weight loss or keeping off lost weight. But even small amounts of physical activity can be helpful. Being active for short periods of time during the day can add up and have health benefits.”
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“Moderate aerobic exercise includes activities such as brisk walking, biking, swimming and mowing the lawn.”
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“Vigorous aerobic exercise includes activities such as running, swimming laps, heavy yard work and aerobic dancing.”
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Source:
How much should the average adult exercise every day?
Edward R. Laskowski, M.D.
7/26/2023
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“The 150 minutes of moderate to intense aerobic activity per week that is recommended by the U.S. Department of Health and Human Services can significantly reduce liver fat, according to new research by Penn State College of Medicine researchers. The team’s meta-analysis of 14 previous studies confirms that exercise leads to clinically meaningful reductions in liver fat for patients with nonalcoholic fatty liver disease.”
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Source:
150 minutes of aerobic exercise per week reduces liver fat, study finds
Zachary Sweger
2/8/2023
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“Recommendations for Adults
Get at least 150 minutes per week of moderate-intensity aerobic activity or 75 minutes per week of vigorous aerobic activity, or a combination of both, preferably spread throughout the week.
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Recommendations for Kids
Children 3-5 years old should be physically active and have plenty of opportunities to move throughout the day.
Kids 6-17 years old should get at least 60 minutes per day of moderate- to vigorous-intensity physical activity, mostly aerobic.
Include vigorous-intensity activity on at least 3 days per week.”
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Source:
American Heart Association Recommendations for Physical Activity in Adults and Kids
American Heart Association editorial staff and reviewed by science and medicine advisors
Last reviewed 1/19/2024
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“The Goldilocks Zone for Exercise: Not Too Little, Not Too Much”
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“Homo sapiens are evolutionarily adapted to be very physically active throughout life, and thus habitual physical activity (PA) is essential for well-being and longevity. Never the less, middle-aged and older individuals engaging in excessive strenuous endurance exercise appear to be at increased risk for a variety of adverse cardiovascular (CV) effects including atrial fibrillation, myocardial fibrosis, and coronary atherosclerosis.”
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“The optimal dose, or what we term ‘Goldilocks Zone,’ of PA may be: at least 150 minutes per week of moderate-intensity aerobic exercise or 75 minutes per week of vigorous-intensity aerobic activity, but not more than four to five cumulative hours per week of vigorous (heart-pounding, sweat producing) exercise, especially for those over 45 years of age. It is also important to take at least one day per week off from vigorous exercise.”
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Source:?
The Goldilocks Zone for Exercise: Not Too Little, Not Too Much
O'Keefe JH, O'Keefe EL, Lavie CJ
Mo Med. 2018 Mar-Apr;115(2):98-105. PMID: 30228692; PMCID: PMC6139866.
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THE RISKS OF EXTREME ENDURANCE TRAINING: Not Exactly Risk-Free - Tied to Adverse Cardiovascular Effects and Remodeling?
Given my background in both competitive middle distance running and echocardiography, I've had an interest in athletic training and its effect on the heart. Oftentimes, the physiological changes that occur from intense athletic training is called the "athlete's heart". This can occur from many sports including running, swimming, martial arts, rowing, etc..
Now, athletic training, including endurance training, for the average person, is viewed as a good and healthy thing. We think of increased stamina, breathing efficiency, and cardiac function. Essentially, they are able to push their bodies very hard for an extended period of time, sometimes measured in 2-3 hours for a full marathon [26.2 miles] or triathlon [The fatality rate for triathlons is approximately twice that of marathons]. On average, it takes an athlete more than 12 hours to complete an Ironman Triathlon [2.4-mile swim, 112-mile bike, and 26.2-mile run].
The paper referenced below, Mayo Clinic Proceedings, June 2012, takes a close look at the heart remodeling that can occur with regular extreme endurance training as well as the associated risks and their statistical frequency. These include:
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CHRONIC TRAINING:
·???????? LV dilatation
·???????? LV hypertrophy
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LONG-TERM EFFECTS:
·???????? Increased cardiac chamber size
·???????? Patchy areas of fibrosis
·???????? Atrial arrhythmias
·???????? Ventricular arrhythmias
·???????? Increased incidence of Sudden Cardiac Death (SCD)
领英推荐
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IMMEDIATE EFFECTS:
·???????? Right heart strain
·???????? RA/RV dilatation
·???????? RV hypokinesis
·???????? Diastolic Dysfunction
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SUBACUTE EFFECTS:
·???????? Cardiac fibrosis
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RISK OF A-FIB:
"Indeed, long-term sustained vigorous aerobic ET such as marathon or ultramarathon running or professional cycling has been associated with as much as a 5-fold increase in the prevalence of atrial fibrillation."
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Source:
Potential Adverse Cardiovascular Effects From Excessive Endurance Exercise
James H. O'Keefe, Harshal R. Patil, Carl J. Lavie, Anthony Magalski, Robert A. Vogel, and Peter A. McCullough
Mayo Clin Proc. 2012 Jun; 87(6): 587–595.
doi: 10.1016/j.mayocp.2012.04.005
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Personally, I keep my cardio workouts to within 1-hour; it usually consists of interval runs or swims, preceded by stretching and some calisthenics. Afterwards I feel "recharged" without being completely exhausted.
One thing to keep in mind is that according to a University of Pennsylvania, Perelman School of Medicine, Department of Preventive Cardiology presenter, after 30 minutes of continuous cardiovascular exercise, there is no additional life-extending benefit. Meaning, you will become more "fit", but after the 30 minutes the data does not show that it will further extend your life. I believe this paper helps us understand, perhaps, why this is.
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ADVICE ON CHOOSING PERSONAL EXERCISE GOALS:
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“When people set their own exercise goals – and then pursue them immediately – it’s more likely to result in lasting positive changes, according to a new study at the Perelman School of Medicine at the University of Pennsylvania. The results of this research are especially important because they were found among an underserved population that is at particularly high risk of having or developing heart conditions. The study was published in JAMA Cardiology. “Individuals who select their own goals are more likely to be intrinsically motivated to follow through on them,” said Kevin Volpp, MD, PhD, director of the Center for Health Incentives and Behavioral Economics (CHIBE). “They feel like the goal is theirs and this likely enables greater engagement.”
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“Many programs, whether offered through work or by health insurance companies, offer incentives for boosts in physical activity. But these goals are often fairly static and assigned based on round numbers. Patel, Volpp, and colleagues believe this research suggests that adjusting goal setting in these programs can have a significant impact. And if these adjustments lead to gains among people with lower incomes, whom cardiovascular disease kill at 76 percent higher rates, that could be particularly important.”
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Source:
Penn Medicine: Choosing Personal Exercise Goals, Then Tackling Them Immediately is Key to Sustaining Change
Center for Health Incentives and Behavioral Economics (CHIBE)
9/1/2021
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BIBLIOGRAPHY:
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How much should the average adult exercise every day?
Edward R. Laskowski, M.D.
7/26/2023
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American Heart Association Recommendations for Physical Activity in Adults and Kids
American Heart Association editorial staff and reviewed by science and medicine advisors
Last reviewed 1/19/2024
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How much cardio should you do?
Harvard Health Publishing
2/19/2020
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What is atherosclerosis?
Cleveland Clinic
Last reviewed on 02/15/2024
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Lung Capacity and Aging
American Lung Association
Page last updated: June 10, 2024
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Exercise and Lung Health
American Lung Association
Page last updated: June 7, 2024
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Massive study uncovers how much exercise is needed to live longer
Sara Berg, MS
1/23/2024
American Medical Association
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150 minutes of aerobic exercise per week reduces liver fat, study finds
Zachary Sweger
2/8/2023
Pennsylvania State University
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The Goldilocks Zone for Exercise: Not Too Little, Not Too Much
O'Keefe JH, O'Keefe EL, Lavie CJ
Mo Med. 2018 Mar-Apr;115(2):98-105. PMID: 30228692; PMCID: PMC6139866.
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What is Fibrosis?
Sally Robertson, B.Sc.
Last Updated: Feb 24, 2023
News Medical Lifesciences
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Penn Medicine: Choosing Personal Exercise Goals, Then Tackling Them Immediately is Key to Sustaining Change
Center for Health Incentives and Behavioral Economics (CHIBE)
9/1/2021
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Moderate vs. vigorous exercise for cancer prevention
Kellie Bramlet
11/2016
The University of Texas MD Anderson Cancer Center
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Potential Adverse Cardiovascular Effects From Excessive Endurance Exercise
James H. O'Keefe, Harshal R. Patil, Carl J. Lavie, Anthony Magalski, Robert A. Vogel, and Peter A. McCullough
Mayo Clin Proc. 2012 Jun; 87(6): 587–595.
doi: 10.1016/j.mayocp.2012.04.005
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Everything to Know About VO? Max
Medically reviewed by Gregory Minnis, DPT, Physical Therapy — Written by Tim Jewell
Updated on August 15, 2023
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