Excessive Cardio’s Path to Weight Gain

Sometimes just the thought of it will my heart rate rise…

The word cardio has become somewhat infamous as an exercise death sentence because it’s been so misused that most people don’t really know what it means nor how to calculate how much of it they’re actually doing. When the general population thinks of cardio, things like jogging on a treadmill and doing the elliptical come to mind. Well, these people are indeed correct. The type of cardio they’re thinking of is called “steady state” cardio.This fad of prolonged cardio gained popularity popular in the 70s when it claimed to be best method for fat loss and longevity.

Steady state  cardio is when your  work intensity and heart rate remain relatively similar throughout the workout.

In recent years, another type of cardio called “high intensity interval training”or “HIIT” has been dominating fitness industry and has become the go to program structure for individuals and fitness pros. What defines HIIT is its strict, uniform work to rest ratio that is established before the workout.By alternating between almost maximal effort and rest periods, HIIT has become known for its rapid fat torching results.

 What defines HIIT is its strict, uniform work to rest ratio that is established before the workout.

Although I’ve understood the biomechanics of exercise for years, I too was a “cardio bunny” spending long hours on the treadmill running myself ragged and avoiding weightlifting. I only became a believer during the last years of my undergrad when I unwillingly had to cut down on my jogging and teach more HIIT fitness classes. After a few months of this, I noticed that I started to have abs for the first time ever! I also stopped dreading my long workouts and the desire to binge every other day on carbs stopped. There are a lot of great progress photos floating around showing off people’s results similar to mine, but rarely do they explain why their body reacted to their new workout so drastically. In an attempt to persuade even the biggest skeptics, here are a few before and after photos of my body transformation. The left column is the result of a cardio heavy regimen and the right is my body on HIIT with about 25% the amount of cardio.

In order to understand how I lost so much fat by simply cutting my running amount in half, you’ll have to understand a couple basics about how our nervous and endocrine system work together. Many of us have heard about the parasympathetic and sympathetic nervous systems and how they are polar opposites. They have such different effects on the body because of the different hormones they stimulate. 

A well-known hormone involved in this process, adrenaline, is the hormone we all produce in stressful situations. When released, adrenaline will also stimulate the release of another of hormone called cortisol, a steroid hormone. While there’s many uses for it, in this article we’re going to focus mainly on its ability to reduce inflammation. Cortisol’s anti-inflammatory abilities are a result of it actually suppressing the immune system’s response to stress.

For example:
If you sprained your ankle your body’s natural response is for the area to swell and fill with lots of nutrient and oxygen rich blood. The injury will also start to hurt instantly.

However, if you sprained your ankle and while running away from a bear at the same time, instead of the blood tending to your ankle, your body will prioritize fueling your legs and heart with that blood to help you run from that bear. Chances are you might also not feel the pain of your sprained ankle until after you’re out of danger. Besides helping in life threatening situations, cortisol is also commonly known for its use in joint inflammation and pain relief via corticosteroid injections.

Just kidding, dont run!

Exercising may not be as stressful as running from a bear but it is still an act of creating a stress on your body, so naturally cortisol levels will increase during exercise. This type of stress is totally fine because your body adapts to it by getting stronger, growing your muscles, strengthening your heart, increasing your lung capacity, and all other sorts of good things. The catch is, too much of a good thing can be bad and the amount of prolonged stress the body endures during steady state cardio elevates cortisol levels for significantly longer periods than HIIT training does. This makes it much easier for someone to overload and burn out adrenal glands.

Exercise is the act of putting stress on your body, so naturally cortisol levels will increase during exercise

Ok so why is this a bad thing?

One way our body responds to overloaded adrenal glands is decreasing its insulin sensitivity. This insulin resistance causes the body to store more fat, especially in our midsection. If under constant stress, even low-level stress, your body will hold on to everything you eat. The body perceives stress as a threat and if constantly threatened, it will want to keep a surplus of emergency energy stored, usually in the form of a muffin top around the waist. Ironically, our body will also have a harder time deriving energy from food, creating cravings and in extreme cases resorting to metabolizing glycogen and muscle wasting aka your body will start eat its own muscles for food, yikes!

Symptoms of overloaded adrenal glands can include a flushed round face and changes in skin texture and/or resilience. Below is a comparison of my face while doing too much cardio to a mainly interval-based training program. Note that even though I walked around at about 10-15lbs lighter, my cheeks were actually larger, swollen and puffier, as well as my skin looking significantly redder.

Besides facial puffiness, I also developed significant acne for the first time in my life and the skin on my face and body scarred and bruised much easier as well. A 3rd symptom of decreased insulin sensitivity is bone thinning, osteoporosis. Unfortunately, after years of repetitive use without proper rest, I ended up giving myself multiple chronic overuse injuries. I racked up 2 bone and reconstructive surgeries, 2 dislocated ribs, and 1 missing foot tendon that weathered away after being torn and ignored all before turning 26. Despite all these precautions, I still firmly believe long-distance running is a great activity and I respect everyone who does it as a both sport or past time. 

Steady state cardiovascular endurance training has a place in every person’s exercise routine.

Finding a good balance and mixing up workouts is the key to optimizing your results. Just remember, if your main goal is weight loss, long bouts of sub maximal cardio will most likely hurt your chances of fat loss in the long run (pun intended). Of course, always talk to your doctor before deciding to try a more intense type of exercise, HIIT is often too much for those with heart and respiratory conditions. If you’re unsure of how much you should be working out, start out every other day and then follow the golden rule of exercise progression:

When upping your workout schedule increase only 1 of 2 factors at a time: duration or intensity.

Next week I’ll be posting an article going a little deeper into what duration and intensity are and how to calculate them. I’ll also focus on explaining the mechanics of HIIT workouts and why it teaches your body to utilize its fat stores better. Until then, try mixing in some resistance or interval training into your running program. If your main goal is better running efficiency, Runner’s World has a great article on runner specific weight training. You should definitely check it out!

Journal of Endocrinological Investigation, 2008, Volume 31, Number 7, Page 587 E. Hill, E. Zack, C. Battaglini, Show All (6)

Understanding the Stress Response
Harvard Health Publishing – https://www.health.harvard.edu/staying-healthy/understanding-the-stress-response

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