How does chronic stress affect metabolism?

Chronic stress changes metabolism through two systems. The hypothalamic pituitary adrenal axis releases cortisol. The sympathetic nervous system releases adrenaline and noradrenaline. Both were built for short emergencies. Sustained for months, they raise blood glucose, shift fat storage toward the abdomen, shorten and fragment sleep, and change which foods look appealing. The size of that effect in ordinary life is smaller than most of the internet suggests, and it rarely acts alone.

What cortisol does to metabolism

Cortisol is not a villain hormone. NIDDK describes its normal work as helping the body maintain blood pressure, regulate blood glucose, reduce inflammation and turn food into energy. The problem is duration, not existence. Cortisol raises glucose by releasing it from the liver and by making muscle less responsive to insulin. That is useful for ten minutes of danger and unhelpful across ten months of a difficult job. Sustained elevation also breaks down muscle protein and moves fat storage toward the trunk.

What genuine cortisol excess looks like

Cushing's syndrome is the condition in which cortisol excess is unmistakable. NIDDK lists weight gain with thin arms and legs, a round face, a fatty hump between the shoulders, wide purple stretch marks, easy bruising, weak muscles, high blood pressure, insulin resistance and prediabetes or type 2 diabetes, and bone loss with fractures. Everyday stress does not produce that picture. Someone who has gained weight during a hard year and has none of those physical findings is usually not helped by a cortisol test.

The route that does most of the damage

Stress usually reaches metabolism through sleep. In a randomized crossover study of twelve healthy young men published in Annals of Internal Medicine in 2004, two nights of restricted sleep lowered leptin by 18 percent and raised ghrelin by 28 percent. Hunger ratings rose 24 percent. Appetite for calorie dense, high carbohydrate food rose 33 to 45 percent. That was a two night experiment in healthy volunteers. Run the same pattern for a year and the arithmetic accumulates.

A workable order of operations: protect sleep opportunity first, then look for a medical cause of the metabolic change, then treat the stress itself with something you will actually repeat. Ask for cortisol testing if you have the physical findings above or you take steroids in any form, including inhalers and joint injections. Before your visit, write down your wake time on a weekday and a weekend, your alcohol in units per week, and how many nights you get under seven hours in bed.