The catabolic phase of the metabolic response to critical illness lasts approximately how long?

• A. 7 to 10 days
• B. 1 day
• C. 3 days
• D. 5 days

Answer: (A)

In critical illness the body shifts into a sustained catabolic state to provide substrates for energy and tissue repair. This catabolic phase is driven by stress hormones and inflammatory mediators that elevate proteolysis and gluconeogenesis, helping supply amino acids and glucose for healing, immune function, and wound repair. That heightened catabolic activity tends to persist for about one to two weeks, with seven to ten days being the typical window for many patients. After this period, if the patient stabilizes and nutrition support is adequate, the body often begins to move toward an anabolic, rebuilding phase.

Shorter timeframes like one day or a few days don’t capture the full extent of the catabolic response, while longer durations aren’t as typical unless illness remains profoundly unresolved. So seven to ten days best represents the common duration of the catabolic phase.