A number of things can cause the body to move from an anabolic to a catabolic state. Cortisol plays a major factor, as it facilitates muscle breakdown, allowing the amino acids in your muscles to be converted into sugar. This stress hormone increases by up to 50% following a workout, making that a prime time for catabolism to occur. Cortisol can also increase due to stress, meaning you are more likely to remain in a catabolic state if you experiencing a major life change. Overtraining, poor nutrition, and a lack of sleep can all increase muscle catabolism as well.
Anabolic processes tend toward "building up" organs and tissues . These processes produce growth and differentiation of cells and increase in body size, a process that involves synthesis of complex molecules . Examples of anabolic processes include the growth and mineralization of bone and increases in muscle mass. Endocrinologists have traditionally classified hormones as anabolic or catabolic, depending on which part of metabolism they stimulate. The classic anabolic hormones are the anabolic steroids , which stimulate protein synthesis, muscle growth, and insulin .  The balance between anabolism and catabolism is also regulated by circadian rhythms , with processes such as glucose metabolism fluctuating to match an animal's normal periods of activity throughout the day.