Endorphin Junkies Beware: Too Much Cardio Scars the Heart

by Paula Jager FitnessComments: 29

exercise junkieThe majority of Americans do not get anywhere close to enough exercise so the idea of “too much cardio” may seem ridiculous at first.

Technological “advancements” and gadgets that supposedly make our lives “easier” have come with a price–decreased physical activity and a host of related health problems.

On the opposite end of the spectrum, some exercise aficionados tend to overdo it thinking more is better.

Physical exercise may not be a drug but it does possess the addictive nature and traits of a powerful pharmacologic agent.  As with any chemical agent that affects biological systems, a safe upper dose limit exists beyond which the adverse effects may outweigh the benefits.

I am not undermining the importance of physical exercise with this sobering statement that yes, you can in fact overdo it in the exercise department, especially when it comes to too much cardio!

People that partake in moderate to vigorous physical exercise on a regular basis are much healthier than their sedentary counterparts.

Extreme exercise, however, is actually counterproductive to great cardiovascular health.

If you are exercising correctly and efficiently there’s no need to workout for more than 30-60 min at a time.

It’s important to get your heart pumping with the right type of metabolic conditioning which will improve the amount of blood oxygen, release endorphins, stimulate your immune system and increase staying power.

But there is a point of diminishing returns to these benefits and research is piling up that continuing that cardio session too long–beyond 60 minutes per day can cause more harm than good.

How?  Read on …

  • Shall we say catabolic state?  Excessive cardio spells breakdown and not in a good way.
  • Excess cortisol is released which not only contributes to more catabolism but chronic disease.  It never ceases to amaze me how many endurance athletes have thyroid problems.
  • Repetitive strain injuries and injuries that won’t heal with continued over exercising.
  • Lowered defenses i.e. weakened immune system. Endurance athletes with chronic respiratory infections are a prime example.
  • Insomnia.

If that’s not bad enough, what does too much cardio do to your heart? You’re obviously exercising to improve its function and adopting lifestyle factors that won’t have you dropping dead of a heart attack, but an excess can be a serious blow to your heart’s health.

How Too Much Cardio Kills

Research done on marathon runners and other endurance athletes who regularly partake in too much cardio show the following characteristics including scarring of the heart muscle.

To some they may be the epitome of fitness and the ultimate show of endurance but the extreme stress on their heart comes with a very high price. . .

  • Extended vigorous exercise such as that performed during a marathon or similar event raises your risk of cardiovascular disease by 7 fold.
  • Long-distance training in general leads to high levels of inflammation and the damage continues long after the race is over.
  • Research has revealed diffuse scarring of the heart muscle along with structural changes after several years of excessive training.
  • Studies show long-term endurance athletes suffer from diminished function of the right ventricle.
  • Increased blood levels of cardiac enzymes–markers for heart injury.
  • Atrial fibrillation (rhythm abnormalities).

Although most people reading this article are not exercising enough it’s still important to understand the dangers of excessive traditional cardio.  Since most of us are not elite level endurance athletes what does this mean for us?  It certainly shouldn’t be used to avoid exercising at all. Exercise is absolutely necessary for health & fitness just not excessive amounts of it.

How Much is Too Much Cardio?

Push your body hard enough for a challenge while allowing adequate time for recovery and repair.  Move like traditional man with short burst of high intensity activities but not long distance running, biking and swimming such as required for endurance events.

Even an hour or more more on the gym’s cardio machines is not a wise idea.

Exercise to feel better, look better and perform better. It will aid in keeping your weight in check, help you to sleep more soundly and give you a better outlook–the reasons are many and most of us will not run into the problem of exerting ourselves excessively.

If you are a high level endurance athlete or think 5 marathons a year is a reasonable goal you may want to seriously reconsider how you train.  Bullet proof your heart through short burst of exertion followed by periods of rest or recovery intervals. Heart attacks never happen because your heart lacks endurance rather they typically happen during times of stress when your heart needs more energy and pumping capacity but doesn’t have it.

For further reading on the subject check out these links:





About the Author

paula jagerPaula Jager CSCS and Level 1 CrossFit and CF Nutrition Certified is the owner of CrossFit Jaguar.  Her exercise and nutrition programs yield life changing results.

You can connect with her on Facebook by clicking here.



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