Stress Response

– by Lee Smith, Ph.D.

Your stress response is a blind reflex, a call-to-arms (and legs) that animates your critical resources for action when you’re threatened.

The grizzly bear cometh and your brain yells to your adrenal gland to release adrenaline and steroid hormones which break out the energy reserves from fat stores. Your heart rate pounds up and blood pressure rises, stretching those rubbery vessels. Body repair and growth systems are suspended and blood is diverted away from your stomach and intestines – no need to digest that meal if the grizzly is digesting you! Blood is instead committed to the big muscles that do the work of fight-flight. Platelets, your bodies Band-Aids, multiply and get stickier and the immune system goes on alert just in case of injury. Ugh, maybe your bladder lets go because those pounds of urine are dead weight. Memory sharpens dramatically with a boost from the steroid hormone cortisol, enabling flash-bulb retention. Your attention and senses sizzle.

This acute stress response can save your life, helping you to take the quickest and most robust action possible. Once the threat is over your body regulates the return to normal, leaving you with some appetite so as to replace the energy used.

You sleep through your alarm and wake with alarm. You realize it’s garbage day and angrily organize your offering, feeling time pressured. You fret about being ten minutes late, but find that it’s no problem when you get to work. Through the day you spill a little coffee on your shirt (arghh!), bump in to that co-worker you had a tiff with (grrrr!), and realize your library book was due back yesterday (dummy!). At home the dog barfs on the carpet, milk gets spilt and the bills pour in. And so the day goes and perhaps the next one, perhaps each day featuring a staccato of these moments.

Most people want the good news first: The good news is that you’ve been menaced by exactly zero grizzly bears. The bad news is that your body rockets through the same grizzly reactions, time after time, day after day, a pattern called chronic stress. Chronic stress isn’t a constant state but is instead an up-and-down, oscillating course of stress reactions. It’s not at all good and here’s why.

If blood pressure flies up and down like the toilet seat, vessels get pounded and stretched too often, losing their rubbery good nature. Little tears in the vessels cause inflammation and those circulating sugars and fats that fuel your big muscles get stuck there and build up over time. Stress causes plaques, vascular problems, bad news. Even the vessels feeding your heart suffer this wear and tear. Very bad news.

Cortisol stimulates appetite after stress and the craving for carbs along with the loss of self-control from the recent upset increases snacking. All that extra sugar and fat from snacking produces insulin, the hormone of plenty, which results in storage of our excess. When fat cells get too full, they become insulin resistant (hello Type II diabetes), and leave those abundant sugars and fats in the blood, where they can add to plaques.

The stress-based combination of hypertension, blood vessel resistance, elevated blood sugar and insulin resistance all interact. Oh, and that fat we store around our middle also acts as a kind of endocrine gland, chemically signalling for more inflammation. Oh, great! More inflammation will just encourage more sticky build up at those sites in our vessels that have been hurt by the hypertension.

I’ll bring you more in the weeks ahead about ways in which we can protect against the damage caused by chronic stress after we look even further into stress and how it impacts us.