Originally Posted On June 21, 2012
I have been looking over a couple of articles and just did not want to narrow it down to 5 reasons so I decided on 7! Here it goes:
1. Aerobic Training Raises Cortisol
As stated in my previous post, aerobic training increases cortisol levels. If your cortisol levels are elevated over a long enough period of time, it can lead to your body storing fat instead of burning it, especially in the abdomen (visceral fat-the fat that sticks to your organ..not good). This also increases inflammation in the body and leads to more fat accumulation.
2. Inflammation and Oxidative Stress from Chronic Aerobic Training
High cortisol levels can also make you age faster. Cortisol increases oxidative substances in the body known as free radicals that produce inflammation whether it is in the brain, heart, gastrointestinal tract, or reproductive organs. Free radicals are produced in an oxygen-rich environment created by increased respiration that goes with aerobic training and results in increased cortisol levels from repeated physiological stress. Free radicals can be normalized by antioxidants (found in superfoods-berries, cherries, green tea, etc) but if there is an excessive amount, the body will not be able to normalize it all resulting in changes to your metabolism as well as accelerated aging.
3. Decreases Reproductive Size and Function and Lowers Androgens in Animals
Even though these results were found from a study done on rats, it is still worth taking note. A study done in the Canadian Journal of Applied Physiology tested the effect of aerobic swimming on rats and found that intense endurance exercise lead to oxidative stress and caused dysfunction in the male reproductive system. The rats were performing three hours of swimming a day, 5 days a week for 4 weeks. This is a lot of exercise, but it is very comparable to aerobic athletes or long-distance trainees. After the 4 weeks, the researchers found a significant decrease in the size of the reproductive organs and lower levels of testosterone, and other related hormones and androgen markers.
(Side note: they also found that by giving rats a vitamin E supplement, it decreased the effects of the oxidative stress.)
4. Aerobic Training Worsens Power
This may not be important to some of you if you do not participate in sports as an athlete or a member of the community softball team. But regardless, sports involve speed, explosiveness, and jumping ability. The more aerobic work you do, the more these important components of any athletic activity will decrease. Think of it this way, the more aerobic leg workouts you do, the worse your vertical will become.
5. Long-term Aerobic Exercise Increases Adrenal Stress and Compromises Immune System
By doing too much aerobic exercise, your adrenal glands can become stressed which will upset the precise balance of steroid hormones that your body produces, potentially leading to adrenal fatigue. Symptoms of adrenal fatigue include: tiredness, anxiety, depression, fearfulness, allergies, frequent influenza, arthritis, reduced memory, and difficulties in concentrating, feeling worn-out, and the inability to lose weight after extensive efforts.
Too much aerobic exercise can also compromise the immune system which puts endurance athletes at a greater risk for infection, particularly upper-respiratory illness. The worst kind of aerobics that leads to pronounced immune dysfunction is prolonged exercise that is continuous, long (90 minutes a session), and of moderate to high intensity (60-80% of maximum oxygen uptake). This can put athletes at a greater risk for illness or longer lasting effects since this kind of training can impact hormone function. No wonder I always had bronchitis as a swimmer!
6. Aerobic Training Worsens Testosterone/Cortisol Ratio Which Impedes Ability to Add Muscle
When the testosterone to cortisol ratio is lowered, your body’s ability to gain muscle mass decreases. Without the ability to add muscle, you will have trouble increasing your caloric expenditure (burning calories-metabolism).
7. Aerobic training increases body fat in stressed individuals by contributing additional stress.
Cortisol is the stress hormone. If you are already going through a lot of stress in your life, adding more to it by doing aerobics will only further impede your weight loss goals and could actually result in fat gain!
Now for all of you high school and college athletes that have to endure aerobic workouts, sorry to say but most likely you won’t be getting out of them anytime soon! For those of you who simply enjoy torturing yourself by long distance training, welp, you are just crazy. But wherever you fall, watch for my next post because it will cover ways to combat the negative effects of aerobic training!
Resourced Articles: The (Many) Negatives of Aerobic Training
Getting Maximum Results Part I – Alternatives to Aerobics