The advice, “Stop worrying! Stress is bad for you” is true, but as with a lot of health guidance, its vagueness makes it less effective.
It’s like when people say that getting lots of sleep is important, or that you should eat more fiber—it’s the kind of thing people might like to do, but will probably keep forgetting to do, because it’s not immediately clear how it will make them healthier.
This video from TED Ed, written by the Emory University professor of medicine Sharon Bergquist, clarifies how worrying actually affects the body, outlining what scientists know so far about the stress-sickness connection.
As the video explains, when you’re stressed, the adrenal glands ramp up the release of the hormones cortisol, adrenaline, and norepinephrine. Adrenaline speeds up your heart rate and can raise blood pressure. Cortisol causes changes in the blood vessels that can, over time, increase the risk of heart attack or stroke. Meanwhile, the brain relays the stress signals to the gut, which changes up its routine to allow your body to focus on the stressor. This is what’s behind that “butterflies in the stomach” feeling, but it can also lead to digestive problems and affect the composition of your gut bacteria.