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  • Declan Chan, Eleanor Cheung & Hanniel Wong

Stress & Its Effects

Declan Chan, Article Writer | Eleanor Cheung & Hanniel Wong, Researchers

Why should you care about stress? Isn’t it just a feeling when you realize you haven’t started with your English essay that’s due tomorrow? In fact, the AIS (American Institute of Stress) reports approximately 120,000 people die every year as a result of stress caused by work. On top of that, healthcare costs from work-related stress totals an average of $190 billion a year! That's more than enough money to buy 2 or 3 small islands to deal with any stress you have (Workplace Stress)!



So what exactly is stress? Stress is a cascade of emission of stress hormones triggered by stressful situations, which can be environmental, such as an upcoming event, or psychological, such as a persistent worry on a certain matter (Harvard Health). Now let's get into the nitty gritty details on the neural aspect of stress and how it affects you physiologically.


Neurobiology of stress and physiological changes

In the occurrence of a stressful event known as a ‘stressor,’ the amygdala sends a distress signal towards the hypothalamus, which triggers a ‘fight or flight’ response. This is prompted when the distress signal activates the sympathetic nervous system by sending a signal to adrenal glands through autonomic nerves. The adrenal glands respond by pumping hormone epinephrine, or adrenaline, into the bloodstream, which circulates the body and brings a series of physiological changes. The heart beats faster than normal, pushing blood into organs of the body. The body also breathes more rapidly to take in as much oxygen as possible which leads to senses such as sight and hearing becoming more enhanced and sharper. This also explains the feeling of butterflies in your stomach due to the heightened senses. Moreover, epinephrine signals the body to release glucose and lipids from temporary energy sites, catalysing the breakdown of these molecules and bringing extra energy to the body. With it, the body can execute the ‘fight or flight’ response - to use physical or psychological means to fend off the stressor, or to think of ways to escape from the stressful situation (Harvard Health). You are essentially pushing your body and mind into overdrive and this process takes time to recuperate.


Negative Effects of Stress

What’s the big deal about stress -- isn’t it normal? How does stress impact my body negatively?

- Prolonged or chronic stress can interfere with memory, increase or decrease appetite, diminish sexual desire and performance, deplete energy, and cause mood disruption

- Interestingly, brief stress can enhance immune activity, but prolonged stress compromises the immune system

  • E.g. Students have reduced immune responses, higher risks of contracting infectious illnesses, and slower wound healing rates during exam times compared to other times of the year

Cardiovascular effects:

  • Stress increases blood pressure

  • Prolonged high blood pressure can damage the heart or cause a stroke

  • In sudden cardiac arrest, stress causes excessive sympathetic activity that sends the heart into fibrillation, contracting so rapidly that it pumps little or no blood (Garret, Bob and Gerald Hough, 2018)

Extreme stress can also lead to brain damage

  • E.g. Hippocampal volume is determined by the hippocampus (a brain region implicated in memory and interpreting environmental contexts) and a new study has found that larger hippocampal volume is associated with recovery of PTSD. Hippocampal volume was reduced in Vietnam combat veterans suffering from post-traumatic stress disorder (PTSD) and in victims of childhood abuse, and cortical tissue was reduced in torture victims who suffered from PTSD

  • Abused individuals had short-term memory deficits and some showed slight intellectual impairment

  • The studies performed on the Vietnam veterans that suffered from PTSD show that there are hippocampal changes in the brain associated with this disorder. The veterans with PTSD showed an 8% reduction in their right hippocampal volume. The patients that suffered from child abuse showed a 12% reduction in their mean left hippocampal volume. Several of the studies have also shown that people with PTSD have deficits while performing verbal declarative memory tasks (Bremmer, 2007).

Hippocampal volume on MRI in PTSD. Smaller hippocampal volume in a representative patient with PTSD (right) relative to a non PTSD subject (left). (Published in final edited form as: Neuroimaging Clin N Am. 2007 Nov; 17(4): 523–ix doi: 10.1016/j.nic.2007.07.003)

Using all of this information, we can better understand the negatives of stress and how it affects us physiologically. The best way to deal with it is to take care of yourself. Eat healthy, exercise, get plenty of sleep, and give yourself a break when you feel unproductive and stressed.



Publishing, Harvard Health. “Understanding the Stress Response.” Harvard Health,

Bremner, J Douglas. “Neuroimaging in Posttraumatic Stress Disorder and Other Stress-Related Disorders.” Neuroimaging Clinics of North America, U.S. National Library of Medicine, Nov. 2007,

Bremner, J. Douglas. “Neuroimaging in Posttraumatic Stress Disorder and Other Stress-Related Disorders.” Neuroimaging Clinics of North America, Elsevier, 9 Nov. 2007,

“Workplace Stress.” Partnership for Workplace Mental Health,

“Hypothalamus-Pituitary Hormones and Their Functions.” Time of Care, 10 Aug. 2017,

Garrett, Bob, and Gerald Hough. Brain & Behavior: An Introduction to Behavioral Neuroscience. SAGE Publications, Inc., 2018.


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