Not the studies I saw but:
"However, there is another hormone closely associated with bodybuilding. This hormone is cortisol, a steroid hormone, and is probably the most underrated of the four bodybuilding hormones overviewed in this article. Cortisol is termed catabolic as it has the opposite effect to testosterone, insulin and growth hormone in that it breaks down tissue.
In fact cortisol, which is released by the adrenal glands under conditions of high mental and physical stress and high temperature, is the body’s primary catabolic hormone. The three main functions of cortisol are:
The reduction of protein synthesis.
The facilitation of protein to glucose.
The halting of tissue growth.
It is therefore essential that cortisol release is controlled if one is to facilitate muscle growth. As well as being released under conditions of stress and high temperature cortisol is also released first thing in the morning. Morning aerobics have been thought to be effective for this very reason.
However this is misguided thinking because exercising on an empty stomach first thing in the morning has been shown to actually intensify cortisol’s effects thus resulting in further muscle loss, and consequently metabolic resistance to body fat loss.
There is not a lot a bodybuilder can do in terms of completely restricting cortisol release as, although cortisol can be problematic for bodybuilders, it is an important hormone nevertheless. The vital functions that cortisol govern are the regulation of inflammatory responses in the body and the balancing of blood sugar in times of stress.
It is excess cortisol that is the problem for bodybuilders not cortisol per se. The dangers of excess cortisol are:
Reduced growth hormone, and testosterone output.
Osteoporosis.
Reduced muscle and increased abdominal fat.
Impaired memory and learning.
Reduced glucose utilization.
Impaired immunity.
Controlling Cortisol Release
Although cortisol release cannot be prevented, it can, and should, be controlled. Controlling the release of cortisol can be achieved by employing the following methods:
Exercise (aerobically and with weights): This may seem like a paradox but correct exercise, although it increases stress, will negate the effects of cortisol in the long term. The key is to not overtrain and to do just enough to adequately stimulate the particular system being training (muscular or aerobic). Aerobic sessions should be kept at between 30 and 45 minutes and weight sessions should be no longer than 45 minutes. The endorphin release from these two types of exercise should offset any release in cortisol."
"The duration, intensity and frequency of exercise will determine the circulating levels of testosterone. Testosterone levels increase most with short intense bursts, while it decreases with prolonged activity especially that of frequent endurance training. During endurance training, testosterone is needed to maintain muscle but frequent extended training doesn’t allow for repair and recovery of testosterone and tissue damage occurs.
Studies show that testosterone levels will elevate with exercise for about 45 to 60 minutes. After this time period, cortisol levels begin to increase and testosterone levels will decline. This decrease has been detected for up to 6 days.
Because you require testosterone for repair and growth, do not train for more than 45 to 60 minutes at a single session. If you feel like you want to exercise or train more, split sessions are recommended. Also do not lift weights and perform aerobic training at the same time. It is also a good idea to vary your workouts and cycle them throughout the year."
"Here you see human growth hormone take a surge within the work out.
You also see testosterone spike at about the 35 to 45-minute mark.
After that both hormones start to subside and cortisol starts to surge.
When you hear the now popular idea that a short intense workout is the best, this is why. After the 45-minute mark you are not getting any more hormonal response.
Diminishing Return
Between the 45 to 60-minute mark, there is no gain for the work you do. Exercising after this point will start to break your muscle down because cortisol will surge. The nervous system takes this intense stress as a warning signal and will make cortisol immediately dominant.
When cortisol surges it suppresses the anabolic hormones testosterone and growth hormone.
The length of the workout to enhance hormonal restoration means keeping it under 45 minutes.
The basic rule is - the more time our body has high levels of anabolic hormones and lower catabolic hormones the better. Over any given period of time we want the cumulative effect to be more time spent in an anabolic state."
"According the University of New Mexico’s Len Kravitz the critical level that results in excess cortisol secretion occurs after about 45 minutes of exercise–some people hit the critical level earlier, others later depending on variety of genetic and other variables.
Two of the effects of excess cortisol are fat retention, it makes your body want to hold on to fat instead of burn it, and muscle catabolism, it makes you body use skeletal muscle for energy.
The muscle catabolism is most pernicious effect of cortisol for people trying to lose fat.
First, cardiovascular activity is very efficient at chewing up muscle tissue, the steps are as follows:
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Conversion from fast twitch muscle fiber to slow twitch muscle fiber, by acquiring mitochondria and relinquishing contractile protein. Smaller fiber, less RMR.
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Excessive Cortisol released in response to the damage to the fiber as a result of the exercise. Cortisol acts as a natural analgesic, but severely hampers protein synthesis and muscle repair.
3 . It has been shown, that high volume cardiovascular exercise can completely deplete satellite cells in muscle fiber, which means no new fiber can grow or existing fiber be repaired.
4 . Growth Hormone levels decline with high volume cardiovascular exercise, which also hampers the repair process. Low growth hormone also accelerates aging.
- To sum it up, you can’t train all day, and you can’t eat no food, but you can always build a bit more muscle, so quit the cardio and concentrate on the weight lifting."
"First, after about 40-45 minutes of any type of exercise — and especially intense weight training — so much cortisol has entered the bloodstream that a shutdown of eicosonoid production will begin. Eicosonoids are autocrine hormones (such as prostagladins) that control all function at a cellular level — i.e., inflammation, vasodilation/constriction, heart rate, body temperature, immune function, etc. In this case, cortisol secretion is a response to stress. As eicosonoid production stops, the body is temporarily allowed relief from pain, which it is sensing from too much from intense exercise. For example, a shutdown of PGE1 and PGE2 (pro-inflammatory/anti-inflammatory) prostagladins would commence. Since pain in this case is relative to some type of inflammation this would allow the body to cope in the short term.
If this persisted, however, all eicosonoids would shut down and the body’s function would come to a screeching halt. This is the same dilemma that doctors face when giving people corticosteroids. At first, all symptoms magically disappear; however, within a few days T-cells begin to plummet and heart irregularities and other key physiological dysfunctions begin to appear. This is because the autocrine hormone eicosonoids are being shut down at the cellular level.
Because of their power, these hormones also vanish in seconds. They are, however, the primary activators and modulators of all body functions and, once they shut down, other hormonal systems (endocrine and paracrine) are sure to follow. Small amounts of cortisol are not so dangerous, because once dissipated, the eicosonoid production returns to normal. As you might surmise, being in the gym 2-3 hours every day is an effective way of increasing to a potentially counterproductive — and even dangerous — level in the body.
Secondly, during moderate exercise like walking, insulin levels diminish and blood glucose levels arise in response to the exercise-related increase in glucagon (the pancreas releases glucagon to balance blood glucose levels). This primarily glucose restoration mechanism works smoothly as long as exercise is maintained at a moderate level. But if the intensity increases, cortisol is released to stabilize blood sugar and insulin levels. More cortisol, more problems.
Third, the more intensely you exercise, the more ATP you must produce in the mitochondria for energy. The more ATP you produce, the more free radicals you make, and a certain percentage of those free radicals slip by the energy production phase. Once “loose” in the body, these unpaired electrons search out other electrons to latch onto and oxidize. These excess free radicals search out essential fatty acids (because of their high-polyunsaturation), DNA (which they can damage), protein, fats and a host of important vitamins that we call antioxidants. Making too many free radicals is almost assuredly a passport to aging because they can potentially damage so many essential nutrients and biologically necessary compounds. Too much exercise, along with eating too many calories, is the most effective way of making excessive amount of free radicals."
"It actually does the body more harm than good, to work out for long periods of time. When you exercise more than 45 minutes, the body begins to produce increased amounts of cortisol, which triggers muscle breakdown.
■Cortisol is able to overpower just about all other hormones in the body.
■Cortisol can cause accumulation of body fat even if you think you are doing all the right things correctly.
■Cortisol will block HGH from doing its job.
High levels of cortisol are known to be the cause of:
■Decreased bone density.
■Increased blood pressure.
■Inhibition of the immune system.
■Muscle wasting.
■Insulin resistance.
■Increased body fat levels.
When exercise is combined with an improper diet:
■Blood sugar fluctuations can elevate cortisol.
■Excessive carbohydrates can elevate cortisol.
■Protein deficiency can elevate cortisol.
■Eating too little can cause cortisol to rise.
■During times of stress, cortisol is elevated.
my respectful opinion of this
