The adrenal glands are located on top of the kidneys and put out many important hormones for our system. The most important is our main stress hormone cortisol. This hormone by nature is a hormone of break down. During times of stress or need for increased energy, our body taps into energy stores at all expense to other tissues. Cortisol causes us to hold on to fat and to use lean body tissue for energy. Therefore, if we have too much of this hormone from increased stress, we will have more extensive break down in our bodies in general. If there is long-term drain on the system we will end up with the inability to remove excess cortisol in response to stress leading to fatigue. This inability to remove excess cortisol is termed adrenal burnout.
Some other minor hormones are important with cortisol production. DHEA and pregnenolone can become deficient if the body has been making too much cortisol over a prolonged period of time. Deficiencies in the cortisol cycle can also result in a "steal" phenomenon from the female hormone system, depleting vital hormones that are necessary for normal physiological function. Many symptoms of menopause can be mimicked by adrenal stress. It is not uncommon to have a woman in her late thirties or early forties complaining of hot flashes and night sweats, as well as severe PMS and cramping, that later turn out to be related to the cortisol system and general metabolic break down rather than an absolute deficiency in female hormones.
Symptoms of adrenal stress/burnout:
Weight gain -- especially around the middle
Facial Weight gain
Decreased muscle mass
Acne — trunk and face
Increased need for sleep
Night sweats/hot flashes
The adrenal glands can be stressed over many years with adrenaline based lifestyles, relying on caffeine, aerobic exercise, sugar, and even stimulant medications. When the fatigue starts it is due to many years of damage, and this in turn can take time to repair. Fortunately it usually doesn't take as long to turn the adrenals around as the damage originally took, but it is not an overnight or weeklong process. Depending on the damage, it can take several years to correct.
If we stress our immune system over many years, we can also strain our adrenal glands. The largest portion of our immune system is in the GI tract --60 to 80%. It is this, highly under recognized, system that can lead to fatigue of the adrenal glands. Food sensitivities, bacterial overgrowth, parasites, poor intestinal flora, excess caffeine and alcohol can all put extra strain on the GI tract and therefore the adrenal glands. It is also of note that when given external steroid medications, that insulin resistance and increased blood sugar levels become apparent. When releasing enough of our own internal steroids due to stress, we can set up our own insulin resistance and therefore type II diabetes. Yes, this system is also important to keep in balance to prevent disease.