Excessive Aerobic Exercise - the Negative Impacts

Before we address the reasons why we shouldn’t exercise excessively, let's first ask the question. Why do we exercise in the first place? There are many reasons why. Some exercise to lose a couple of pounds here and there, while others might say it’s because they want to appear more toned and have cardiovascular endurance. However we're not here to decipher the human psyche.... (Let’s face it no one knows how long that could take!). In contrast to these reasons, this may be the first time you have heard the statement that too much exercise it bad for you. This article will tell you why and then you can determine for yourself if you should or should not let exercise rule your life.

When it comes to exercise how much is too much? That’s a great question! This is difficult to define as every one’s body is different.

Towelling off After Excercise

Exercise plays an important role in supporting your health, your immune system and stamina. Without movement your organs would not receive the oxygen and nutrients they need to function. Toxins and natural waste byproducts would accumulate and take longer to leave the body. Body systems like the lymphatics and cardiovascular would become stagnant and muscles would weaken. So it’s clear exercise is important, but how much is too much and what are the consequences of the tremendous amount of stress that excessive amounts of exercise may place upon our health and bodies? We know that stress (either physical or emotional) can eventually lead to disease. Let's look at the facts about exercise intensity, stress, thyroid hormones and general metabolism and you can decide for yourself.

We all know the important roles played by thyroid hormones. They affect growth, metabolism and tissue differentiation. They also increase fatty acid oxidation and thermoregulation. In other words, whenever we exercise thyroid hormones are involved; what's critical here is the intensity of physical activity and its effect on thyroid hormone levels.
When we train, thyroid hormones are secreted and the rate of our metabolism increases. This continues to a certain point during exercise. After this, the thyroid decreases hormone secretion in an effort to save energy. Less thyroid hormone secretion, equals less energy consumption required by the body. You see, your body is trying to maintain homeostasis, so continuing to exercise and pushing it to the limit, will inhibit its ability to adapt. Instead, the body will only have enough energy to maintain the activity and not enough to burn stored fat. Wait a minute! Isn’t that the whole point of all your HARD work?! Ultimately, instead of utilising fat stores to burn stored fat, you will use protein stores from muscle breakdown for energy, and thus enter a catabolic state.
If excessive exercise regimes are followed without care being taken to ensure that the thyroid (and adrenal glands) they can become exhausted and unable to function efficiently. This can then cause weight gain rather than weight loss. In fact high performance athletes complain that they gain weight after a competition. This is because their thyroid glands become exhausted.
This temporary hypothyroid state reflects a reduced secretion of the thyroid hormones. This is due to the fact that there's less activity in the thyroid gland. In layman's terms, you exhausted your thyroid gland and now it's taking a rest.
What will happen if your stubborn determination persists and you continue to engage in high intensity exercise? The hypothyroid state can continue, but this time in addition to the weight gain, other signs of hypothyroidism will appear. This can wreak havoc on all your hard work and time given to training.
Some studies were able to partially block or prevent altogether the progression of hypothyroidism or what other studies call a low T₃ syndrome. T₃ stands for triiodothyronine. It's one of the two thyroid hormones responsible for general metabolism. It's a lot more potent than T₄ (thyroxine). The researchers instructed the volunteers to increase their caloric intake appropriately. This method was able to inhibit the development of hypothyroidism.

In the end, can you deduce what happened here? Our ultimate desire, determination and dedication can undoubtedly overcome physical barriers. In doing so, we tend to over train or exercise excessively. To make matters worse, we do not increase our caloric intake in the hope that our bodies will burn stored fat.

Making the 3D's (desire, determination and dedication) a constant, we can successfully accomplish our goal (whatever it is we're aiming for: improved fitness, health, or the ‘perfect’ body, etc.) by increasing our caloric intake and continuing to perform moderate to intense exercise (for 20 to 30 minutes) or by maintaining our caloric intake, but decreasing our exercise level from light to moderate exercises (for 30 to 40 minutes).

For a reference regarding exercise intensity, use the following: light (or low) intensity is about 45 to 54% of your maximum heart rate (MHR), medium intensity is 55 to 69% of your MHR and high intensity is anything greater than 70% of your MHR. Your MHR is determined by using this formula, 220 – your age = MHR. For example, if you're 35 years old, your MHR is computed as follows, 220 – 35 = 185. One hundred eighty five is your MHR. If you want to engage in light intensity exercise, multiply 185 by 0.45 (from 45%) and you get 83.25, which you round off to 83. Around eighty three beats per minute should be your target heart rate while doing light intensity exercises.

It is up to you which of the two scenarios you choose. No one can tell you exactly how you can lose those extra pounds. A significant portion of that endeavour rests on how you feel and there's no better person to tell you that, than yourself. The most important part is that you now know that excessive exercising, CAN lower T₃ levels and may lead to hypothyroidism.

Woman Running

Summary

Take it easy. Don't tire yourself out to the point that you can no longer retract your tongue from hanging out because of exhaustion! Determine your goal, increase caloric intake and continue the moderate to high intensity exercise or maintain caloric intake and perform light to moderate intensity exercise. Bottom line is, allow your body to catch up with that thing you call your brain. Sometimes it, (your brain) forgets that it needs the body to survive. Of course, don't forget to feed them both with adequate nutrition.