A recent article in the lastest Oxygen was this:
Regardless of your career, you likely battle high levels of stress, which directly impact your metabolism and ability to burn carbs, protein and fat effectively. Stress can spark an outpouring of the primary stress hormone cortisol, which is important for the normal metabolic rate and digestion and absorption of foods. With excess amounts, the body is more likely to pile on fat and break down muscle mass. Cortisol also puts the brakes on the thyroid gland, which is essential for keeping your metabolism in check, adding to the vicious cycle that promotes fat accumulation and muscle loss.
As an active woman and athlete, it's especially important to work on ways to manage stress and cortisol levels in order to reap the benefits of your training. That may mean cutting back on the number of workouts you do in order to alleviate stress with efficient programs, learning to say "no" at work or setting stricter boundaries to help you manage your life.
Cortisol is produced by the adrenal glands and released as part of the body's "fight or flight" response. Although fine to rise when you are late for an appointment, giving a presentation or requesting a raise, if cortisol is constantly elevated due to a micromanaging boss, lack of sleep, long commute or other factors, it can be counterproductive to what you're trying to accomplish in the gym.
Chronically elevated cortisol levels are thought to be associated with a host of health problems such as an accumulation of belly fat (the type most harmful to our heart), an increase of the eat-more hormone ghrelin, poor sleep, moodiness, a sagging sex drive and poor athletic performance.
I know first-hand about this - it happened to me! And is something I'm currently working on with the help of my coaches/mentors.