The Stress You Don't Have to Stress About

By: Kerry Buckhaults  

March 2025

Stress is an inevitable part of life, a shared experience among us all. We try to avoid introducing stress into our daily lives as much as possible, and it is often thought of as only a negative experience. However, there is such a thing as positive stress! Scientists call this eustress and have been recently trying to harness its benefits. Unlike distress, the negative form of stress we try to avoid, eustress is attributed to positive effects on the body and mind. Eustress is short in duration, brought on by stimulating factors, promotes motivation, and provides resilience to future stressful events (1, 4). Hard to believe there's a positive form of stress? Think about the last time you took on a tough project at work. It may have been difficult in the moment, but did you show up each day motivated to get things checked off your to-do list? Did it force you to converse with people you wouldn’t have the chance to otherwise? How did you feel when a portion of it worked out better than you imagined? Maybe the experience even motivated you to volunteer for other projects in the future. Or think of the last time you challenged yourself in the gym, and once you hit a personal record you felt an immediate rush of accomplishment. Both of these scenarios require the feeling of stress, but you may have experienced eustress without even knowing it! 

Our Stress Response System 

When we think about stress it is often as a reaction to our external environment, but in neurobiology the focus is more on the effect it has on our internal environment. Our cells rely on a delicate balance of nutrients, water, gases, and temperature to remain healthy, which scientists call homeostasis. When homeostasis is disturbed it results in cellular stress. Unfortunately, studies have linked prolonged cellular stress to structural changes within our brains that have long term effects on our immune system, memory, and even our cardiovascular system (8, 9). These widespread effects are largely due to the hypothalamic pituitary adrenal axis (HPA axis), which is thought of as our body's stress response system (3). The HPA axis connects the hypothalamus, which is the portion of our brain that is responsible for maintaining homeostasis, to our pituitary gland. The pituitary gland is a pea sized structure at the base of our brain that secretes adrenocorticotropic hormone (ACTH), which is a chemical messenger that communicates to our adrenal glands above our kidneys to start releasing cortisol, which is our body’s stress hormone. This process is bidirectional, meaning that the cortisol that is released returns to the brain and causes adaptive responses throughout the body. These adaptive responses can include an increase in inflammation, higher blood pressure, unstable blood sugar, or issues with our body’s energy reserves, all of which contribute to the long-term effects of stress (3, 8, 9). The HPA pathway is also responsible for immediate effects of stress, think about how common stress headaches are! This is due to the cortisol released by the HPA axis communicating with your cardiovascular system to increase your blood pressure (8). Some people even report headaches as a form of stress (9), making the regulation of your HPA axis even more complicated. 

Can Our Brains Tell the Difference Between Stresses? 

Our brains rely on chemical messengers to receive and relay information to the rest of our body. Cortisol acts as one of these messengers, and scientists think that if the adaptive responses triggered by the HPA axis are able to achieve homeostasis following a stressor it is considered eustress, but if this balance is not restored it is considered distress (2). However, this is a poor way of distinguishing between types of stress because there is no clear timeline in which homeostasis must be achieved following a stressor for it to be positive. Alternatively, some scientists think that the distinction comes from the balance of input your brain receives from the environmental stressor. Two other chemical messengers that send signals throughout our brain are Glutamate (GLU) and GABA, with GLU being excitatory and GABA being inhibitory.

These chemicals are called neurotransmitters and are used by neurons in our brain to communicate about what our bodies are experiencing. Think of these messengers as turning on a switch (GLU) vs. turning off a switch (GABA). In a study comparing short durations of stress (eustress) to long durations of stress (distress) there were differences in the balance of GLU/GABA within the brain (4). In the eustress condition both neurotransmitters increased equally, however in the distress condition there was significantly less GABA input than GLU. The distressed treatment also had poorer memory performance when compared to the eustress treatment, suggestive of a beneficial effect of short-term stress exposure (4). Across these two different theories it seems that a proper balance is important for the positive effects of eustress, whether it be adaptive responses triggered by the HPA axis returning to baseline functioning or balanced GLU/GABA input to the brain, suggesting that our brains do have a way of differentiating between positive and negative stress.

Being able to distinguish between positive and negative stress may be conserved over time. Believe it or not fish also experience stress, and a recent study used different types of stressors to see if a fish’s brain reacted differently to each type (7). Food reward was used as an eustress trigger, and distress was triggered by exposure to air. Cortisol levels were significantly higher in the fish exposed to distress when compared to the fish exposed to eustress, but if either stress lasted longer than an hour the cortisol levels were comparable. This suggests that in small doses there are different responses between positive and negative stressors, but if the stress persists the difference diminishes and the body reacts the same (or maybe even worse if we consider the GLU/GABA imbalance that emerges after prolonged stress). The human body may have conserved the ability to discriminate between positive and negative stress as a social tool. We produce chemical signals that give clues to others about the state of our bodies, called pheromones, which we secrete through sweat. A common side effect of stress is sweating (thanks to our adaptive responses spiking), and our pheromones “smell” differently based on what caused us to sweat. One study collected sweat from people who were in a stressful situation (right before sky diving for the first time) or during physical activity. People who were exposed to stressful sweat had an increase in brain activity, and were more accurate in identifying threatening images (6). Distinguishing between positive and negative stress pheromones has not yet been investigated, but if our brains are able to tell the difference perhaps it is possible that we send different signals to other people as a way of communicating the type of stress we are experiencing.  

Hopefully the knowledge that our brains can react differently to eustress and distress is a stress-reliever, but how can we promote the positive effects of unavoidable everyday stress? Clinicians have been trying to introduce programs that assist in managing daily stressors so that the negative effects are minimized; however, every individual has different stimuli they find stressful and reactions to stress vary from person to person. Learning to recognize how you personally react to stress and adjusting this so that it does not stimulate your HPA axis is one way to manage the negative outcomes (3). This can be accomplished by a technique called biofeedback, in which adaptive responses are monitored and users receive a cue when functioning is dysregulated (8). Patients are guided by a trained professional to learn to regulate their bodily response(s) to stress in hopes of returning to homeostasis quicker. Another approach is to reframe the expectations that the individual has when encountering daily stress (5). This can entail educating an individual on the different outcomes of stress prior to the stressor (you’re already doing this by reading this post!) or reflecting on the experience after the stressor (pay attention to how you feel next time you are late for your train). So, although it sounds backwards, do not avoid stress in your life. Instead, pay attention to how your body responds and use this to inform your next challenge!

References: 

1. Bienertova‐Vasku, J., Lenart, P., & Scheringer, M. (2020). Eustress and distress: Neither good nor bad, but rather the same?. BioEssays, 42(7), 1900238. 

2. Engelmann, M., Landgraf, R., & Wotjak, C. T. (2004). The hypothalamic–neurohypophysial system regulates the hypothalamic–pituitary–adrenal axis under stress: An old concept revisited. Frontiers in neuroendocrinology, 25(3-4), 132-149. 

3. Guilliams, T. G., & Edwards, L. (2010). Chronic stress and the HPA axis. The standard, 9(2), 1-12. 

4. Lin, L., Zhang, J., Dai, X., Xiao, N. A., Ye, Q., & Chen, X. (2022). A moderate duration of stress promotes behavioral adaptation and spatial memory in young C57BL/6J mice. Brain Sciences, 12(8), 1081. 

5. Liu, J. J. W., Reed, M., & Vickers, K. (2019). Reframing the individual stress response: Balancing our knowledge of stress to improve responsivity to stressors. Stress and Health, 35(5), 607-616. 

6. Mujica-Parodi, L., Strey, H., Frederick, B., Savoy, R., Cox, D., Botanov, Y., ... & Weber, J. (2008). Second-hand stress: neurobiological evidence for a human alarm pheromone. Nature Proceedings, 1-5. 

7. Pawlak, P., Burren, A., Seitz, A., Glauser, G., & Pietsch, C. (2022). Differential effects of acute eustress and distress on gene regulation patterns in the carp (Cyprinus carpio L.) brain. Aquaculture Research, 53(14), 5075-5096. 

8. Sic, A., Bogicevic, M., Brezic, N., Nemr, C., & Knezevic, N. N. (2025). Chronic stress and headaches: The role of the HPA axis and autonomic nervous system. Biomedicines, 13(2), 463. 

9. Yaribeygi, H., Panahi, Y., Sahraei, H., Johnston, T. P., & Sahebkar, A. (2017). The impact of stress on body function: A review. EXCLI journal, 16, 1057.