"Too much cortisol, again caused by the adrenal glands’ response to excessive stressors, causes the tissues to no longer respond to the thyroid hormone signal. It creates a condition of thyroid resistance, meaning that thyroid hormone levels can be normal, but tissues fail to respond as efficiently to the thyroid signal. This resistance to the thyroid hormone signal caused by high cortisol is not just restricted to thyroid hormone but applies to all other hormones such as insulin, progesterone, estrogens, testosterone, and even cortisol itself. When cortisol gets too high, you start getting resistance from the hormone receptors, and it requires more hormones to create the same effect. That’s why chronic stress, which elevates cortisol levels, makes you feel so rotten—none of the hormones are allowed to work at optimal levels....When cortisol is high the brain also is less sensitive to estrogens. That’s why you can have a postmenopausal woman with reasonable amounts of estrogen, but when you put her under a stressor and her cortisol rises, she’ll get hot flashes, which are a symptom of estrogen deficiency. She really doesn’t have an estrogen deficiency, the brain sensors have just been altered. If you then drive the estrogen levels up with supplementation to treat the hot flashes, she’ll start getting symptoms of estrogen dominance like weight gain in the hips, water retention, and moodiness. And the hot flashes usually don’t go away.
This is why you often can’t effectively treat someone with hormonal imbalance symptoms such as hot flashes by simply adding what seems to be the missing hormone, be it thyroid, progesterone, estrogen or testosterone. If your cortisol is chronically high you’ll have overall resistance to your hormones....Cortisol is released from the adrenal glands in a rhythmic pattern throughout the day. It’s high in the morning, which energizes you. If you don’t have enough cortisol in the morning you have a hard time getting out of bed. It’s at its lowest levels at two a.m. when melatonin is high. Melatonin and cortisol are inversely related, so when cortisol is down and melatonin is up you’re regenerating your body. When your cortisol stays high you also won’t produce enough growth hormone or thyroid-stimulating hormone, which are important anabolic [tissue building] hormones. This is why a good sleep is so important. People with high salivary night cortisol levels are usually complaining of sleep problems." http://www.virginiahopkinstestkits.com/cortisolzava.html
