Our modern lifestyles are full of events that can aggravate stress. Whether it is the busy, hectic work schedules, family or relationship stresses, our addition to technology, the financial pressures from the modern economy, we seem more stressed than previous generations at the same age.

In the US, 25% of people admit to experiencing high stress while another 50% experience medium levels of stress. https://www.webmd.com/balance/stress-management/stress-and-the-body#1.

From an evolutionary point, stress and anxiety are supposed to make us make the correct decisions by increasing our concentration, motivation and avoiding high-risk situations.

Compared to our ancient ancestors who were always on their toes, hunting for food or fending off dangerous animals, you’d think they experienced higher stress than us.

But, mental health issues are now more strife than ever in human history. The key difference is that back then, stresses lasted for a short duration whereas now, many people experienced prolonged levels of stress or chronic stress.

Another difference is that in historical times, stress was an accurate response to real life-threatening situations. But, in modern times, stress is a response to trivial events that aren’t life-threatening. This is because modern life has blurred the difference between dangerous and harmless situations in life.

Stress can be beneficial in small doses but when it’s prolonged, it starts to affect us both physically and mentally. Chronic stress has been linked to serious health conditions like depression, hypertension, and obesity.


The Biology of Stress


A trigger for stress will send a message to the hypothalamus (command centre of the brain) from the amygdala (area of the brain that overlooks sensory information). The way the amygdala processes or interprets a stimulus as dangerous or not, will be different from person to person based on their genetics or life experiences.

Basic survival activities such as breathing and pumping blood are controlled by your nervous system. The nervous system is comprised of two parts, the sympathetic and parasympathetic systems.

Your hypothalamus is co-ordinated with your nervous system, so if the hypothalamus encounters what it thinks is a stress trigger, it will cause the sympathetic nervous system to respond chemically. This chemical response is referred to as the ‘fight or flight’ mechanism and is designed to give you the physical energy needed for fending off a life-threatening situation.

In the ‘fight or flight’ response, the sympathetic nervous system is actuated by the hypothalamus. This will call for a chemical response from the adrenal glands to release adrenaline.

Adrenaline will lead to an increase in heart and breathing rate, an increase in blood sugar levels and increase blood flow into the muscles. All this is to physically prepare a person for battling or running away from danger.

However, another hormone that gets released as a result of the fight or flight is cortisol. Cortisol is meant to keep people focused and alert on their surroundings.


Long term physical effects of stress


All of the changes in your body mentioned previously are only meant to last a short period of time until the trigger is gone. However, issues arise when there is chronic stress and these chemical changes can lead to more serious health issues over a long period of time.



  • An increased breathing rate can increase oxygen to your muscles, but it can also lead to hyperventilation, panic attacks for chronic stress patients. These are worse for people who suffer from respiratory conditions like asthma.

  • An increased heart rate and blood pressure in the fight or flight response is meant to increase blood flow to your muscles. However, if the heart rate remains high, it can lead to a host of serious health conditions. For example, the high blood pressure can lead to high inflammation in the arteries and affect cholesterol which could, in turn, increase the risk of heart attacks or strokes.

  • Increased muscle contractions were originally designed to physically prepare you for a fight or running away from the stressor. Over longer periods, it could lead to chronic pains.

  • An increased blood sugar level from the liver was meant to deliver energy to your body’s cells quickly. However, this can be risky for some people who are predisposed to Type 2 diabetes.

  • Increased levels of cortisol over prolonged periods have also been linked to weight gain and irregular thyroid function. Hence, stress can make it harder to lose weight for people who are already overweight.


Other secondary effects of stress


Not only can chronic stress have a direct physical effect on your body, it can also have other secondary effects that are also harmful to your health.


  • Stress affects your digestive functions. Since the hypothalamus controls your whole body including your gut, it will call for chemical responses that will affect your digestion too. In order to prepare for physical activity, your body may divert blood flow meant for digestion into the muscles instead. It can also lead to inflammation in the gut and other digestive issues like nausea, heartburn or constipation. Over long periods, these issues can cause nutrient deficiencies.

  • There have also been links between stress and depression. Studies have linked stress with the suppression of new neurons in the brain. So, it can make certain parts of the brain smaller affecting everyday activities such as speech.

  • Some research studies have shown that prolonged stress can weaken your immune system, increasing the likelihood of catching colds or infections.

  • Stress has been linked to worsening of skin conditions like eczema and rosacea. Additionally, there is some evidence to show that stress can slow down the repair and growth process of skin cells.

  • Because stress leads to a chain of chemical responses in the body, it can mess with normal biological processes controlled by hormones as well, such as menstruation. Increased stress has been linked to irregular or even absent periods in women.

  • Prolonged stress in pregnant women has shown links to autism, ADHD and other mental health issues in the unborn baby.

  • Stress can lead to imbalances in the hormones controlling hunger, leptin and ghrelin. This can lead people to overeat as people can lose a sense of fullness and overestimate how hungry they are.

  • Stress and anxiety can mess up people’s sleep schedules and deprive them of quality sleep. Higher levels of stress have been linked to insomnia. In turn, a lack of sleep can negatively affect the processes of growth and repair in the body.


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