Cortisol and Thyroid hormone
It seems like everyone is on thyroid hormone replacement nowadays. Whether it is an inability to secrete thyroid hormone, or other things are affecting metabolism is difficult to know. We certainly were not prescribing tons of thyroid extract a hundred years ago. Thyroid hormone does more than just raise metabolism, it affects organs like the brain and Gastro-Intestinal system. Thyroid hormone interacts directly with cortisol. Some of the signs of low thyroid hormone secretion are brain fog, weight gain, feeling cold and constipation. If you are on thyroid hormone replacement, it is important to address your cortisol because these two hormones work in parallel. When we make thyroid hormone, mostly T4 is produced along with some T3 which is released into your bloodstream. T3 is the active thyroid hormone that is responsible for increasing metabolism. In the bloodstream an iodine molecule must be removed from T4 to become T3. There are two forms of T3 made, T3 and reverse T3. Reverse T3 is biologically inactive and it is overproduced when cortisol is under produced. The purpose of reverse T3 in life is to make us feel bad and is akin to putting on the brakes because the cortisol reserve is not optimal. Many of these studies are from patients in the intensive care unit where the stress is hardly imaginable. There are glandular therapies, taking Armour Thyroid or Nature-Throid for thyroid support are tools for our adrenals to work better.
Cortisol and Testosterone
Testosterone and cortisol also have to be in balance. Cortisol has a negative effect on testosterone and will prevent muscle development. If you look at the difference between endurance and sprint athletes, the endurance runners are always lanky, with underdeveloped muscle (though powerful) and the sprinters are much more developed. The endurance runners are likely secreting too much cortisol in relation to testosterone. Growth hormone is secreted at night and highest around 2 am. High levels of cortisol at night will adversely affect the secretion of growth hormone. This means that you will not sleep well or repair cells.