Stress is our body's physical or behavioral response to events that alter our homeostasis, or the internal balance required for life under normal circumstances. When we encounter perceived threats or pressure—known as stressors— a biological chain reaction occurs to sharpen our minds, boost our performance, and heighten our immune response.
Hours of research by our editors, distilled into minutes of clarity.
Stress activates the “fight-or-flight” response when we face threats. It’s triggered by the hypothalamus, which signals the release of adrenaline and cortisol, heightening awareness and energy. While acute stress helps in short bursts, chronic stress—persistent over time—can harm both physical and mental health, leading to conditions like hypertension, anxiety, or depression.
The physiological response to acute stress generally involves two phases—the "fast" response in which adrenaline is released, and a second "slow" response in which cortisol is released. This technical resource reviews what happens in the body during each phase.
Elevated acute levels can enhance the immune system's ability to fight off infection or respond to injury. Chronic heightened cortisol levels, however, can lead to inflammation that harms cells and tissues over time.
Hormesis—mild or moderate stress followed by recovery—helps make us more resilient. A stress expert speaking during this roughly 30-minute CNN special explains that our bodies depend on periodic mental and physical challenges to activate our innate defense mechanisms, spurring cellular repair and regeneration.
The body's reaction to acute stress involves two responses: fast and slow. The first occurs immediately, with the central nervous system triggering the release of adrenaline. The second releases cortisol, which elevates blood sugar and blood pressure and restricts nonessential functions like digestion and the immune system.
Stress is our body’s internal mechanism to deal with changes in our internal balance. As such, the stress response affects nearly every organ system through a cascade of both fast and slow hormonal changes. While short-term stress can be adaptive, long-term stress may cause serious health issues.
When the body experiences stress, the sympathetic nervous system releases the hormone norepinephrine. This hormone prematurely activates pigment-producing cells (melanocytes) in hair follicles, which depletes the hair's ability to retain color over the long run.
Researchers have shown that being around someone who is stressed can trigger a stress response in your body, such as elevated cortisol levels and elevated heart rate. One way this was recently studied was by having people watch stressful activities, like a recorded job interview or solving challenging math problems, and then sampling hormones in observers' spit.
Stress is a normal part of everyday life, and it’s not necessarily all bad. But chronic stress—the kind that leads to burnout—can change the size and functioning of parts of your brain. It can alter the ability to make new brain cells and memories and even potentially modify your DNA.
Considered Yale University's most popular free online course, this 10-module series offers insights into the science of well-being and practical ways to increase happiness and satisfaction. More than 5 million people have enrolled since its 2018 launch.
Discover a broad spectrum of topics, from fundamental anatomy to the latest in medical research and treatments, all aimed at enhancing your understanding of health, wellness, and our bodies. Our resources are meticulously curated to offer precise and pertinent information to students, professionals, and anyone interested in learning more about the medical sciences. Dive in to stay informed, make well-informed health decisions, and explore the intriguing world of medicine.