Endocrinologist Stafford Lightman
“ We're not designing a drug to give to everybody who's stressed. But this can be very important and hopefully should actually be an extremely useful treatment for … depression that's associated with severe stress. ”
Chronic Stress Can Significantly Damage Health
An interview with Stafford Lightman, Endocrinologist, Bristol University, England
Q: What are the origins of the stress response?
A: Stress is an extremely important protective mechanism for human beings, and in fact for all animals, because if you're being chased by a lion it's important to get away. In order to get away you need to give as much oxygen and as much sugar to your muscles to make them work as fast as they can, so your blood flow needs to go faster. When you're being frightened, your brain detects the danger, it sends signals down your spinal cord to your adrenal medulla to release adrenaline. The adrenaline increases the amount of sugar in your blood and increases your heart rate, and this helps your efficiency of getting away from the lion. Your brain also sends signals down to the pituitary gland, which releases another hormone which acts on the outside of the adrenal, the adrenal cortex, and that releases cortisol. Cortisol is also very important in keeping your blood sugar up, keeping your blood pressure up, and helping allow the body to have maximal exertion to get away from danger.
Q: What happens to the body as a result of the stress response in the brain?
A: One of the fascinating things that happens is [that] the body is being prepared only to use its really essential functions, so the muscles work well, the liver releases more sugar, for energy, but things are actually being turned off as well. Although the heart rate is going up and more blood is going round the body, parts of the body which aren't needed urgently are being turned off. The blood supply to the gut and areas like this is actually decreased, so your digestion diminishes—you don't need digestion when you're running away from a lion—obviously your sexual function is turned off, and a lot of the non-essential activities of the body just decrease so that you preserve the really essential ones to get away from the dangerous situation.
In a modern situation we don't have these same sorts of dangerous problems, but what we have are other very stressful situations. And the interesting thing, of course, is that your blood sugar goes up, your heart rate goes up and your blood pressure goes up, but you're not utilizing all of this, you're not running away, you're not having energy, so all of these hormonal responses are happening, but they're actually not being used.
