Today everyone thinks that exercise, intense exercise, is the key to living longer and healthier.
Nobody questions it. And yet it wasn’t always so.
Up until the 1960s, it was believed that intense exercise was bad for the organism.
And in fact, is there evidence that intense exercise may actually be harmful?
That’s what this study out of Iran addresses.
They took two groups of 10 women each for this study.
All of these women are very similar and lead similar lifestyles.
They are 20 to 28 years old. They are all inactive, sedentary, and they don’t exercise but they are healthy and they are not obese.
So with 10 of the women, the controls, they have them not do any exercise beyond whatever activity they normally would engage in.
And the other group of women is given running, jogging, and intense exercise to perform.
But they are only to exercise for 25 minutes, three times a week.
The primary exercise was running on the treadmill for 25 minutes.
The women did a 5-minute warm-up and a 5-minute cooldown.
Each week focused on a different intensity level for the exercises.
60%, 65%, 70%, 70%, 75%, 75%, 80% and 85% of maximum heart rate.
Notice something interesting here?
These are not outrageously ridiculous levels of activity.
My maximum heart rate is probably about 190, so if I were to go on this regime, my first week I would be at a heart rate of 114.
That’s much lower than I normally exercise that which is 135 to 140.
Now take a look at the extraordinary results.
In these women, stress hormone levels skyrocketed.
Cortisol levels indicate stress in the body.
The purpose of cortisol is to lower inflammation, so having higher cortisol levels indicates that there is inflammation that the body is fighting off.
Cortisol also is a hormone that is present to maintain blood sugar levels when blood sugar gets low, such as when fasting are exercising.
The most important thing you know about cortisol is that it’s catabolic.
Catabolic means that cortisol breaks sugars and other compounds from larger molecules into smaller ones for energy.
It even tears down muscles molecules.
When you’re exercising, you generally want to put on additional muscle.
But cortisol is catabolic so it is tearing down muscle.
This indicates that even this training regime constitutes overtraining for these out of shape women.
And the same lesson goes for anybody man or woman, young or old.
DHEA is probably familiar to you already — it’s a steroid hormone made by the adrenal glands.
DHEA in both women and men exhibits a wide variety of important hormonal functions.
Fast-rising DHEA indicates a body under stress:
So let’s look at the extraordinary results.
So for cortisol, the level of cortisol in the women who were training was almost ten times as high as the levels for the non-training group.
And DHEA skyrocketed also.
These women were under stress even with three times a week, fairly moderate exercise.
This is not an extraordinarily high cortisol level, but it is very high compared to the control group.
It shows that exercise is MUCH more stressful on the body than we think it is.
We can to a large extent use “mind over body” and force ourselves to exercise intensively.
But to what end?
If stress hormones skyrocket, is it really good for you to exercise this way?
As they say in the study,
Numerous studies have been conducted on factors of hormones overtraining, and overtraining has caused an increasing IL-6 and this leads to increase lipolysis and thus it stimulates cortisol and other cytokines.
Overtraining is exactly what is happening here.
As the researchers note, overtraining increases IL-6, which is an inflammatory chemical.
And it stimulates cortisol as we’ve seen, which actually breaks down muscle.
Intense exercise also causes lipolysis, which is fat burning that can lead to insulin resistance and even diabetes.
This is why it’s important always to exercise within your existing fitness level.
What should you do next?
You might want to consider just getting active, rather than doing a lot of running around and gym exercises.
You don’t need to have your cortisol and DHEA levels measured, you can see for yourself that you feel good and you feel positive about your activity or your exercise.
You never have to push yourself.
If it’s a joy to go or to start, then in those cases, you’re doing great.
If it’s stressful, if you need the motivation to go, if you feel like you’re dreading it, then it’s absolutely positively stressful for you, and probably causing stress hormones that probably make the exercise worse than useless.
The kinds of exercises that you dread or don’t look forward to are causing you to lose muscle mass, lose fitness, and suppress your immune system.
- The Effect of Endurance Training on the Ratio of Serum Cortisol to Dehydroepiandrosterone (DHEA) in Inactive Young Women
- Cortisol blood test
To continue reading about intense training and other topics that pertain to men, click here. If you’d like further information, feel free to check out these references:
- Training for intense exercise performance: high-intensity or high-volume training?
- Exercise intensity: How to measure it - Mayo Clinic