Why Do Cold People Shiver?

I’m sure pretty much everyone, especially here at Penn State, is familiar with the discomfort of going outside and being so cold that your body involuntarily shakes. Just thinking about such icy temperatures sends a chill down my spine. But why do we shiver? Why do our teeth chatter?

screen-shot-2016-11-17-at-9-08-43-amImage Found Here

Allan Hemingway of the Department of Physiology, The Medical School, University of California at Los Angeles, California, in an APS Physiological Reviews journal, wrote an article and conducted a study about shivering. Shivering is, according to the article, a defense mechanism for when the body is endangered by cold temperatures. Our bodies are trying to protect themselves from hypothermia. It is an involuntary action that occurs with body systems and parts that people usually use intentionally, which is interesting. Oxygen intake increases when people shiver, as mentioned in another study Hemingway alludes to in the article.

Hemingway conducted a study on animals (including people) to measure their shivering in both quantitative and qualitative ways–both numerical and conceptual non-numeric ways. For example, metabolic rates were compared between neutral temperatures and exposure to cold with a shivering response. This is qualitative data.  Shivering was also measured by visual cues, mechanical methods, and EMG (Electromyograms).

The study found that shivering was different from animal to animal. For examples, rabbits with thick fur coats were much less inclined to shiver at all compared to people when exposed to severe cold. There were also different temperatures at which animals started to shiver. Rats were also most likely to not shiver, but to control and warm up their bodies in alternative ways (non shivering thermogenesis).

This study is observational and likely does not suffer from the Texas Sharpshooter Problem or the File Drawer Problem.

Teens Health suggests that the hypothalamus in our brains regulates our body temperature. It signifies when we should sweat from being too hot or shiver from being too cold. By shivering, we are converting energy stored in our bodies to heat.

According to Wouter Van Marken Litchenbelt, author of Cold Exposure–an approach to increasing energy expenditure in humans in Vol 25 Issue 4 of Science & Society of Trends in Endocrinology & Metabolism, obesity is caused by more caloric intake than energy expenditure. In other words–people eat entirely more than they burn off. Someone who eats a family sized bag of chips and lays on the couch in front of the TV all day is someone who probably consumes more than they work off with exercise. There have been suggestions to implement exposure to the cold to help people to expend more energy and increase their metabolic rates. People shiver when they get too cold. The subtle shaking and jerky movements that occur from shivering help people to use up energy and generate heat. An obese person who is subjected to shivering will start to use up more energy, and possibly lose some weight!

So it seems that shivering is one of the many ways our bodies are always protecting and defending themselves. It’s cool that we have so many defense mechanisms that we don’t even have to think about in order for them to happen.

6 thoughts on “Why Do Cold People Shiver?

  1. Anna Josephine Wisniewski

    Molly, this is such a great topic. You did an excellent job relating the information to class by bolding commonly used terms! I think you could have possibly elaborated as to why the Texas sharpshooter problem and file drawer problem couldn’t happen in this case. More than just simply saying it is observational. This concept of shivering by tensing and relaxing our muscles when cold is one of the many amazing ways our body aims to protect us. I had initially thought it was simply a way for our bodies to react to the shock of the cold, not to actually raise our body temperature. If you think about it, the parallel concept of shivering is sweating. We sweat to regulate our body temperature. This short video shows a great comparison between shivering and sweating.

  2. Thomas Tatem Moore

    Molly,

    This is a very well written article with a relatable topic to many students at Penn State. with the cold weather ramping up this is a very relevant topic to write on. Living in Pennsylvania my whole life, I’ve done my fair share of shivering and “teeth chattering”. During the action I often wonder how it happens and why it happens. This article does a great job of explaining both. I was very surprised to hear that it is actually a defense mechanism from our body. I also found it interesting that enough of the action could burn enough calories to lose weight. Here is a video I found adds on to what you said about why we shiver.

  3. Kaitlyn A Kaminski

    Molly,

    Thank you for writing this because I have always wondered what causes someone to shiver. I am naturally always cold and walk around with a blanket no matter the season in my house because that’s just how my body is. I found it to quite interesting how this is a defense mechanism and you took what Andrew said in class and tied it into your post. I knew that the body defended itself from getting too cold/too hot, but I am glad that you explained why this must happen in order to live. Our bodies are doing incredible things every day and I am glad you chose to discuss this. In this abstract (http://physrev.physiology.org/content/43/3/423) and there is the full journal on the next page- it is discuss why we shiver/how our body responds with different levels. Great job writing this and keep up the good work!

  4. Michael Robert Szawaluk

    Molly,

    This is an excellent and informative post. Everyone has shivered at some point and at Penn State we will be doing it a lot more of it in the upcoming months. We shiver as a part of homeostasis, or how our bodies regulate temperature. I found some data points here: http://www.brighthub.com/science/medical/articles/112024.aspx A normal body temperature is 98.6 degrees. If our body temperature drops below 91.4 degrees, we lose consciousness. At 82.4 degrees, muscles fail. While we shiver when we are effected by colder weather, we also get the chills and shiver when we have a fever. Our nervous system will begin to break down when the human body reaches 107.6 degrees and we will die if it reaches 111.2 degrees. In the case of a fever, we shiver due to being overheated and our bodies work to release the heat. Doing some research, I came across an interesting article about fevers: http://www.everydayhealth.com/cold-and-flu/why-do-we-get-chills-with-a-fever.aspx

    which states that our brains know when to reset to a higher than normal temperature to fight off bacteria and viruses. That reset causes our bodies to work hard to elevate our temperature. Even though the body temperature is rising, the current temperature is lower than what our brain has internally set it to, and that is why we shiver. Overall, I enjoyed reading this blog. Your comments were well-organized. Now I won’t mind shivering as much since I know it can help you lose weight, as you referenced from the Litchenbelt article.

  5. Jason Williams

    Molly,

    I think it’s very interesting the shivering is a defense mechanism for our body. There’s so many interesting things the body does without our explicit action to protect ourselves. When reading your piece about shivering, it made me think about the discussion we had in class about why our fingers wrinkle when wet. Like shivering, it was very confusing for a long time, until the connection was made between wrinkled fingers and wet condition tires. The extra ridges in the tires allows better traction and gripping on slippery surfaces and this is the same with wet fingers.

    For more info, here’s the source: Scientific American

  6. Samuel Sae Jong Lee

    Molly,

    Why people shiver is an interesting topic to write about and I liked how you approached the question. The Hemingway study showed that different animals shivered in different amounts but I was hoping you would go more into detail as to why this particular study suffers from the Texas Sharpshooter Problem or the File Drawer Problem rather than just stating that was the case. I was also confused on how the last study tied into shivering in the cold even though it may have been really clear from your perspective. Otherwise I thought the blog was well written and I hope you continue to put out good work.

    -Sammy Lee

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