WHEN WE come across an overwhelming situation, we automatically tend to blurt out “I’m so stressed!” While people react to different degrees of stress in their own way, it is not pleasant to experience an unwanted emotional rush. However, an emotional rollercoaster ride may not always be bad for our well-being. In fact, stress can bring several benefits for our body and mind.

Biology behind stress

   So what happens inside our body when we encounter a stressor, the stimulus that triggers stress? The stressor causes a chain reaction[1] in our stress response system called the hypothalamic-pituitary-adrenal (HPA) axis. For example, a stressor could be an exam that we have the next day, which we forgot to study for. Once our body perceives this stressor, the hypothalamus, a small area located in our brain, receives the message. Although not large in size, the hypothalamus is important because it maintains our body’s homeostasis, regulating the body’s internal conditions. Some of the ways it serves to balance our bodily functions is by releasing hormones, regulating body temperature, and managing sleep[2]. As such, the hypothalamus allows us to stay awake while we cram late into the night for our exam. Not only is the hypothalamus in control of our homeostasis, but also when activated by the stressor, it sends a chemical message to the nearby pituitary gland. The pituitary gland, also referred to as the “master” gland, then sends signals to other glands to secrete more hormones. Thus, when we are cramming for our exam, the glands secrete cortisol—the stress hormone—into the blood, which circulates throughout our bodies. When cortisol is released into the bloodstream, our body starts to increase sugar levels—glucose—so that we have more energy to face the stressful situation. With this energy being delivered to and consumed by brain cells, our brain is fueled up to concentrate on studying for the exam. The increase in blood sugar level is what instigates a fight-or-flight response[3], which gives us a burst of energy as our heart rate and blood pressure increase.

   Although short-term cortisol exposure can help, experiencing high levels of stress hormones over an extended period is unhealthy. There are two types of negative stress: acute and chronic stress. An acute stress reaction occurs when we experience a particularly stressful event. It leaves a short-lived negative impact on our body including wanting to be alone, having poor concentration, and feeling irritable. These negative impacts are present during times when we go through a bad breakup or get a speeding ticket. We can recover from acute stress quickly, but if the body constantly receives stressors, acute stress can develop into chronic stress, which causes serious damages to the body. Going through emotional abuse, physical abuse, or feeling pressured at work are all examples of chronic stress. Depending on the severity of the stressor, it can cause insomnia, depression, stomach problems, or even a heart attack in serious cases[4].

Finding positivity in stress

   On the other hand, eustress—also known as manageable stress—is a type of stress that causes positive changes in our body. Eustress is produced during enjoyable situations in our life such as getting a job promotion, welcoming a newborn home, or learning a new hobby. Unlike negative stressors, eustress allows us to feel fulfillment, motivation, and vigor. Surprisingly, manageable stress has numerous benefits. Daniela Kaufer (Associate Prof., UC Berkeley) who studies the biology of stress, found in a series of experiments that moderate levels of stress improve learning and memory through hormonal changes in laboratory rats[5]. When rats were exposed to moderate stress by having them immobilized for a few hours, stem cell[6] growth was stimulated, which formed brain cells called neurons. Neurons, which help our body react to sensory input and send motor commands, are an essential component of the nervous system. These brain cells were generated less when the rats were exposed to higher levels of stress by immobilizing them for days or exposing them to the smell of predators. Thus, the unique benefits of stress pertain to eustress only. So what is the biology behind the increased formation of neurons? Dr. Shelton (Vice-Chair, Dept. of Psychiatry, Uni. of Alabama at Birmingham) stated moderate stressors stimulate the production of neurotrophins, a brain chemical essential to the function of neurons[7]. Increased generation of neurotrophins strengthens the connection between neurons, which overall allows for better cognitive performance. 

   Manageable stress, in the short-term, has the added benefit of boosting our immune system. Our immune system heightens when it faces a stressor because it naturally prepares the body to defend itself from possible injuries or infection[7]. Dr. Shelton states, “One way it does this is by producing extra interleukins—chemicals that help regulate the immune system—providing at least a temporary defensive boost[7].” In other words, more interleukins entail a stronger immune system. This immune boost is further explained by Firdaus Dhabhar, the lead author of Stress-Induced Redistribution of Immune Cells—From Barracks to Boulevards to Battlefields: A Tale of Three Hormones. In the study, Dhabhar demonstrated that exposing laboratory rats to mild stress caused a mobilization of various immune cells into their bloodstream[8]. Dhabhar explained the movement of immune cells is “comparable to the mustering of troops in a crisis[8].” As such, our bodies are even more capable of dealing with stress than one may assume. Having both health and performance benefits, eustress is necessary for a healthy lifestyle. 

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   Instead of trying to avoid stressful situations altogether, we should change our perception of stress. People normally tend to try to distract themselves to mentally escape from stress-inducing situations. However, it is more conducive to focus on the present, and try to recognize the type of stress you are dealing with. If it happens to be Eustress, fret not, and let your brain make use of the temporary boost in mental functions.

[1] Chain Reaction: A sequence of chemical reactions in which its products cause succeeding reactions to occur

[2] Healthline

[3] Fight-or-flight response: According to Britannica, it is a response to a threat that causes physical changes in the body, preparing us to either react or retreat.

[4] Mayo Clinic

[5] Greater Good Science Center

[6] Stem cell: A type of cell that can develop into different types of specialized cells in the body

[7] Health

[8] Stanford Medicine