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Biology 103
2002 First Paper
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Why Stress Affects Us Physically

Kyla Ellis

Why Stress Affects Us Physically

We deal with stress daily. In our every-day vocabulary "stressed" becomes an emotion as in: "How are you?" "I'm feeling happy, how are you?" "I'm feeling stressed." It is a negative word, and is not an emotion we aspire to. But if "stress" comes from the nervous system, why does it affect our body? Why does stress cause us to lose sleep, break out, and become depressed? In my paper, I will attempt to explain what stress is, how it happens, and then what it does to our bodies and why it does those things.

First, let me clarify: Stressors are internal or external factors that produce stress. Stress is the subjective response to the factors (10). All humans and animals have developed internal mechanisms through evolution that allow our bodies to react to a stressor. The term "stress" has a negative connotation, but it can also be a positive thing, such as when performers go onstage, they rely on stress to provide the adrenaline rush necessary to helping them perform. Most stress is not due to life-threatening situations, but rather to every-day occurrences such as public speaking, or meeting new people. I'd like to point out also that the intensity of stress depends on how it is perceived. For example, a deadline contraction can be for some people an opportunity to manage their time more efficiently, while for others it can be the end of the world.

There are four categories of stress. The first is Survival Stress. The phrase "fight or flight" comes from a response to danger that people and animals have programmed into themselves. When something physically threatens us, our bodies respond automatically with a burst of energy so as to allow us to survive the dangerous situation (fight) or escape it all together (flight). The second is Internal Stress. Internal stress is when people make themselves stressed. This often happens when people worry about things that can't be controlled or put themselves in already-proven stress-causing situations. The third category is Environmental Stress. It is the opposite of Internal Stress, it is caused by the things surrounding us that could cause stress, such as pressure from school or family, large crowds, or excessive noise. The fourth category is called Fatigue and Overwork - This kind of stress builds up over a long time and can take a hard toll on your body. It can be caused by working too much or too hard at a job, school, or home. It can also be caused by not knowing how to manage your time well or how to take time out for rest and relaxation. This can be one of the hardest kinds of stress to avoid because many people feel it is out of their control (3).

One site I looked at compared a person undergoing stress to a country whose stability is threatened. The country reacts quickly and puts out a number of civilian and military measures to protect the country. On the one hand, the readiness to quickly respond in such a way is vital to the long-term survival of the nation; on the other hand, the longer this response has to be maintained, the greater the toll will be on other functions of the society(10).

Stress affects us physically, emotionally, behaviorally and mentally. When there is a threat, the body physically reacts by increasing the adrenaline flow, tensing muscles, and increasing heart rate and respiration. Emotions, such as anxiety, irritability, sadness and depression, or extreme happiness and exhilaration come out. Behaviorally, one might possibly experience reduced physical control, insomnia, and irrational behavior. Mentally, stress may severely limit the ability to concentrate, store information in memory and solve problems ("Test anxiety" happens because the brain has a reduced ability to process information while under the effects of stress) (1).

Has anyone ever told you they were stressed out because of acne? The fact that they are stressing out about it might be making the problem worse. How can what happens on your face be related to what happens to your central nervous system? Acne forms when oily secretions from glands beneath the skin plug up the pores. There is a stress hormone known as corticotrophin-releasing hormone (CRH). An increase in the CRH signals oil glands in the body urge the oil glands to produce more, which can exacerbate oily skin, thus leading to acne(4)(5).

If people are stressed, they may lose sleep due to the fact that there is something on their mind, making it hard for them to stop worrying about it long enough to fall asleep. However, stress hormones also make it harder to sleep. CRH has a stimulating effect and when it is produced in the body in greater quantities, it makes the person stay awake longer and sleep less deeply. In this way, stress is also linked to depression, because people who do not get enough "slow-wave" sleep may be more prone to depression(6).

The hippocampus is an important part of our brain and its functions. The hippocampus is responsible for consolidating memories into a permanent store (9). The hippocampus is the part of the brain that signals when to shut off production of stress hormones called cortisol. However, these hormones can damage the hippocampus. A damaged hippocampus causes cortisol levels to get out of control, which compromises memory and cognitive function, creating a vicious cycle(7).
In conclusion, stress is not just simply a process that overtakes the central nervous system. It affects the body in many different and seemingly unrelated ways. To live a healthy lifestyle includes striking a good balance between work, down time, and sleep, which should help reduce the effects of stress.


1)Coping with the Stress of College Life ,
2)Staying Well ,
3)Understanding and Dealing with Stress
, 4)Science News,
6) Stress and Sleep deprivation ,
7)The Cortisol Conspiracy and Your Hippocampus,
8) Stress Management ,
9)The hippocampus of the Human Brain,
10. 10) The Neurobiology of Stress and Emotions,

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