What is stress?
Stressful situations abound in our lives. Tornadoes, wildfires, flash floods, and hurricanes upend lives across the country. News of economic woes and dishonest politicians seems to play in endless loops. And that’s not even counting the day-to-day hassles that can grind you down.All of this can be deeply unsettling. Worse, thissteady onslaught of stressors, both large and small,can harm your health over time. Many studies linkchronic (long-term) stress to major killers like heart disease and stroke. Other common physical manifes-tations of stress include headaches, back pain, trouble sleeping, and irritable bowel syndrome.Sometimes you can take steps to dial back the stress in your life. But more often, you can’t change the world around you. What you can change is how you perceive stressful situations and how resilient you are. This report will highlight new research that shows just why stress management is such a powerful tool.Equally important, it will give you a smorgasbord of techniques for coping with stressful situations.But before delving into solutions, it helps to undersand and just what stress really is, for encountering a stressful situation is not the same thing as under-standing what’s happening inside your body at the same time.
A look inside the stress response
Since then, scientists have learned much more about the body’s response to stress. It involves the brain, the autonomic nervous system, and a cascade of hormones and other substances that rule involuntary body functions such as breathing, blood pressure, and heartbeat. It’s a complicated relationship, but one that’s worth understanding. Your response to threats begins in the thalamus, apart of the brain that receives and processes information from the senses—perhaps the sight of your boss wearing an ominous expression, or the sound of an explosion. Instantly, your thalamus alerts the brain’s fear center, the amygdala, and other emotional centers of the brain, which then send signals to the brain’s cortex. From there, the message to respond and divert the body’s energy speeds down nerve pathways to muscles, which tense and tighten, bracing for trouble. This diverts the body’s energy from digestion and other less-pressing needs. Another signal from the amygdala goes to the hypothalamus, a portion of the brain perched above the brainstem (which controls many critical functions like breathing and heart rate). The hypothalamusthen relays the warning to the nearby pituitary gland, which sends a chemical messenger via the blood-stream to the adrenal glands, located above the kidneys. In response, the adrenal glands secrete a series of stress hormones, including the first hormone that Cannon isolated—epinephrine, commonly known as adrenaline. You’re probably familiar with the so-called adrenaline rush that helps rev up your body. The adrenal glands also release a second stress hormone identified by Cannon, called norepinephrine, or noradrenaline. Other researchers added a third discovery—the stress hormone cortisol, also produced by the adrenal glands. When you’re faced with a stressful situation, all three begin coursing through your bloodstream, producing a broad range of physiological responses (see Figure 1, at left). Simultaneously, the hypothalamus fires up the autonomic nervous system. This network of so-called sympathetic nerves relays the warning down through the spinal cord and from there to nerves throughout the body. In response, nerve endings in organs, blood vessels, the skin, and even sweat glands release epinephrine and norepinephrine.
By Harvard Medical School
