The Science of Stress, And Its Effects

Stress is a common word these days. With challenging economic scenarios and a dwindling work-life balance, it is unsurprising that our generation is facing more stress than our ancestors. Despite this, the science of stress remains poorly understood by most of the global population. Stress comes in different shapes, but its effects are obvious to us, and even to those looking. Sleep deprivation, consistently being on edge, anxiety and even physical illness are some of the more obvious effects of stress. The science behind anxiety is somewhat distinct though, and we’ve covered it separately. With constant worry and fear from a range of sources – it’s not such a shock that we get worried fairly easily. Add to that some unexpected pandemic crises and the fear of contracting the illness and anxiety about the anticipated economic issues, and we have a recipe for disaster.

But of course, simply because it’s understandable to be stressed out, doesn’t mean it’s a desirable or acceptable state for our bodies to be in. In fact, since stress is caused by a more physical reaction in the body, it has some definite physical effects which could prove very harmful – even fatal! There is a definite biological basis for stress, and most of its consequences are physiological. Here’s what we know about the science of stress – what causes it, and its consequences.

Biological basis of stress

Whenever we encounter a situation which puts us under pressure, the nervous system activates our “fight or flight” response, releasing stress hormones like adrenaline, noradrenaline and cortisol. These hormones are designed to produce changes in our bodily functions to help us cope with the perceived danger by increasing our heart rate, constricting or dilating blood vessels and slowing down our digestive processes. Historically, when hunting for food was the norm and survival was people’s only concern, such a response made sense, but now, the same response has been adapted to react to even emotional threats, which can prove harmful. 

Effects of Stress

While there is such a thing as positive stress or Eustress which motivates us to step out of our comfort zone and helps build our resilience and self-efficacy, most of the time, stress can become overwhelming, causing distress. This affects almost every vital function of our body.


One of the immediate effects of stress is felt in our respiratory system. The stress hormones increase our breathing rate to speed up the circulation of oxygen-rich blood through the body. This reaction could lead to shallow breathing, causing minimal air to be taken in, which can result in hyperventilation. Although this is not an issue for a majority of us, people with asthma and those prone to anxiety and panic attacks would face the brunt of the respiratory effects of stress.

Musculo-skeletal functions

Our musculoskeletal systems are also affected by stress, because our muscles tense up in response to the release of the stress hormones. This muscle tension is our body’s natural way of shielding itself from pain and injury, a direct result of the “fight-or-flight” response. If this happens occasionally, it wouldn’t cause much of a problem. However, repeated muscle tension can cause aches and pains. When such tension occurs in the shoulders, neck or head, it’s also likely to cause tension headaches or migraines.

Cardiovascular functions

The stress response causes blood vessels to constrict, making the heart’s work of pumping blood harder. This leads to high blood pressure, and increased cortisol levels makes the issue worse. When the stress is acute, these effects are temporary and functioning returns to normal when the stress has passed. However, when it is experienced repeatedly, it can cause permanent damage to blood vessels and arteries, increasing the risk of cardiac arrest, hypertension or stroke.


The cortisol released as part of the stress response tends to suppress our body’s inflammatory pathways and several functions of our immune system, wreaking havoc on it. This immune suppression greatly weakens our body’s ability to fight off illness. This is, perhaps, one of the more frightening effects of stress, as a weak immune system makes our body vulnerable to any number of infectious diseases.


The stress response triggers a slowdown of the digestive processes, which can lead to either overproduction of digestive acids, which causes painful acid reflux, or their underproduction, which limits the stomach’s digestive power. A lack of stomach acid can leave food in the system for too long, leading to bloating, inflammation of the intestinal tissue and reduce the absorption of nutrients. Besides, cortisol increases the appetite for carbohydrates and sugar (quick energy), prompting overeating. Cortisol also puts excess glucose in the system, which gets stored as fat in the body, making us gain wait.

Mental health

One of the most obvious, and more devastating effects of stress, is on our mental health and emotional well-being. While high and low moods are a normal part of life, stress can cause us to feel more tired and more irritable than usual. It can also cause hyperarousal, which leads to insomnia and restless sleep. This not only impairs overall concentration, attention and learning, but can also cause chronic health problems and depression.

Endocrine functions

Stress is mainly caused by the response of our body’s endocrine system to perceived danger or stressful situations. It releases hormones and activates the “fight-or-flight” response, causing a cascade of other physiological effects. But chronic stress (long-term stress) or repeated acute stress tend to push the endocrine system, particularly the adrenal gland, into overdrive, wearing it out completely. This can lead to a condition known as “Adrenal Fatigue”, whose symptoms include exhaustion, weakness, hormone imbalance and depression.

Indirect effects

There are several direct physiological and psychological effects of stress. However, they are not the only effects. The way we cope with stress could cause additional, indirect health problems. Unhealthy coping mechanisms like chronic drinking, smoking or drug abuse, which may provide temporary relief but come with a host of health problems.

Stress is unhealthy. In fact, one can even go so far as to call it a silent killer. Even some of the coping mechanisms that people employ to relieve stress tend to compound the effects of stress. There are, of course, several healthy coping mechanisms that can help build our resilience and combat stress. Deliberate rest and relaxation through techniques like controlled breathing and meditation, a healthy and balanced diet, mindfulness and regular exercise are all effective in relieving stress. It is important to practice these various techniques regularly, so that our stress can be managed before it manages us.