The body is meant to protect and support us. When faced with a threat, whether it be to our physical safety or emotional equilibrium, the body’s defenses kick into high gear in a process known as the “fight or flight” response. The sympathetic nervous system pumps out adrenaline, preparing us for emergency action. Our heart rate and blood flow to the large muscles increase, the blood vessels under the skin constrict to prevent blood loss in case of injury, the pupils dilate so we can see better, and our blood sugar ramps up, giving us an energy boost.

The stress response is what helped our stone age ancestors survive, enhancing their ability to fight or flee from danger. But in the modern world, most stressors are psychological, rather than physical. Caring for a chronically ill child or getting audited by the IRS qualifies as stressful situations, but neither calls for either fight or flight. Unfortunately, our bodies don’t make this distinction. Like a caveman confronting a saber tooth tiger, we go into automatic overdrive, releasing the same hormones that enabled prehistoric humans to move and think faster, hit harder, see better, hear more acutely, and jump higher than they could only seconds earlier.

The problem with the stress response is that the more it is activated, the harder it is to shut off. Instead of leveling off once the crisis has passed, your stress hormones, heart rate, and blood pressure remain elevated. Extended or repeated activation of the stress response takes a heavy toll on the body. The physical wear and tear it causes includes damage to the cardiovascular system and immune system suppression. Stress compromises your ability to fight off disease and infection, makes it difficult to conceive a baby, and stunts growth in children. It can even rewire the brain, leaving you more vulnerable to everyday pressures and mental health problems such as anxiety and depression. And, of course, the stress of living with a debilitating disease or disorder just adds to the problem.