Cortisol is activated by the hypothalamus, and integral part of your hormone system. Hot flashes tend to coincide with the hormone imbalance that comes with menopause – wherein all the hormones, including cortisol are in a state of imbalance. Hot flashes will keep you up at night, thus increasing your cortisol, which in turn increases the likelihood of hot flashes during menopause. It can be a vicious cycle. But if you can bring cortisol into rhythm, then the other hormones can start doing what they are supposed to, and this in turn, can results in a reduction of hot flashes.