There are many signals that control catabolism. Most of the known signals are hormones and the molecules involved in metabolism itself. Endocrinologists have traditionally classified many of the hormones as anabolic or catabolic, depending on which part of metabolism they stimulate. The so-called classic catabolic hormones known since the early 20th century are cortisol , glucagon , and adrenaline (and other catecholamines ). In recent decades, many more hormones with at least some catabolic effects have been discovered, including cytokines , orexin (also known as hypocretin ), and melatonin . [ citation needed ]
As we age, the balance slowly shifts towards a more catabolic dominant metabolism, initiating the many physical and energetic changes we associate with later stages of life. The body becomes less efficient, losing the ability to keep pace with the rate of break down that is occurring. This shift results in decreased energy levels, physical deterioration, increased susceptibility to illness and injury, and longer recovery times. While this is a natural process that everyone experiences, the choices we make over the course of our lives can greatly improve our body’s ability to age gracefully. A healthy lifestyle that includes proper diet, regular exercise, and good rest is essential.