Nick S.
Posts: 2
Joined: Thu Oct 18, 2007 10:17 am

how the human heart responds to a gradual decrease in oxygen

Postby Nick S. » Fri Oct 19, 2007 10:35 am

Can anyone help me with my interview questions?

I am investigating how the human heart responds to a gradual decrease in oxygen and an increase in carbon dioxide in the bloodstream. What would happen to my heart rate if I held my breath for 15 seconds? What would happen to my heart rate if I held my breath for 45 seconds?

Besides heart rate, what other physiological things would occur if I held my breath for 15 seconds? For 45 seconds?

Do males and females respond differently to a decrease in oxygen and an increase in carbon dioxide; if so how are they different? Do children and adults respond differently to a decrease in oxygen and an increase in carbon dioxide; if so how are they different?

Do you have any additional insights concerning this topic of study?

Thank you for all your help.

Nick S :)

MelissaB
Moderator
Posts: 1055
Joined: Mon Oct 16, 2006 11:47 am

Postby MelissaB » Fri Oct 19, 2007 12:50 pm

Hi,

This is a great question (although I suggest you do not do any experiments on this as it could be very dangerous!). The following website should answer some of your questions, and the links in the article will take you to other sites that will answer the rest. http://en.wikipedia.org/wiki/Anoxia. If you have more questions after you've read through these sites and the sites they cite, let me know.

One phenomenon you might want to look into is altitude sickness in humans, which involves a lot of physiological changes due to low air pressure at high altitude.

Another thing you might want to think about is how the levels of O2 and CO2 in the blood are actually generated. For example, I would expect males, females, adults and children to respond the same to given levels in the bloodstream, but I would expect them to react differently to a particular high altitude because of differences in body size that in turn create differences in the levels of oxygen and carbon dioxide in their blood.

Louise
Former Expert
Posts: 921
Joined: Mon Jan 16, 2006 2:17 pm

Postby Louise » Fri Oct 19, 2007 12:57 pm

MelissaB wrote:Hi,

This is a great question (although I suggest you do not do any experiments on this as it could be very dangerous!). The following website should answer some of your questions, and the links in the article will take you to other sites that will answer the rest. http://en.wikipedia.org/wiki/Anoxia. If you have more questions after you've read through these sites and the sites they cite, let me know.

One phenomenon you might want to look into is altitude sickness in humans, which involves a lot of physiological changes due to low air pressure at high altitude.

Another thing you might want to think about is how the levels of O2 and CO2 in the blood are actually generated. For example, I would expect males, females, adults and children to respond the same to given levels in the bloodstream, but I would expect them to react differently to a particular high altitude because of differences in body size that in turn create differences in the levels of oxygen and carbon dioxide in their blood.


I just wanted to add to what Melissa said. Don't plan an experiment where you deprive a person of oxygen. This is very dangerous. Most science fairs don't allow testing on humans or animals; and if testing is allowed, it is only if you will do no harm. Thus, testing like this on humans or animals would probably get you disqualified from the science fair even if no one got hurt.

See the links on this page for more information:
http://www.sciencebuddies.com/mentoring/project_src.shtml

I'm glad you are thinking about your science project and I hope you post back here with another (related) idea that is safer to test.

Good luck!

Louise

Willz
Former Expert
Posts: 44
Joined: Tue Oct 02, 2007 10:28 pm

Postby Willz » Fri Oct 19, 2007 5:00 pm

As Louise and MelissaB have mentioned, this experiment can be quite dangerous, and it is generally not recommended. However, if you still want to do a project on Heart Rate and Declining Oxygen Levels, one idea would be to conduct research on the difference in heart rate of someone that is still compared to someone in motion (i.e. sleeping person vs. running person). Then, you could also test the difference between fast breathing and slow breathing and how it affects heart rate. These are just suggestions, but you are free to manipulate them or come up with your own.

James
Former Expert
Posts: 52
Joined: Sat Sep 10, 2005 5:19 pm

Postby James » Fri Oct 19, 2007 8:28 pm

Hi Nick,

The physiology of heart rate, blood, and the role of oxygen and carbon dioxide has been thoroughly researched in the scientific literature. It is a fascinating area of science; the field of cardiology still has many questions. I highly suggest you do a good reading on this area before embarking on any experimental ideas.

For people with a normal heart rate and no signs of serious cardiac diseases, measuring heart beat or rate after manipulating oxygen or carbon dioxide levels will probably reveal little or nothing. The body, as you may imagine, has remarkable compensatory mechanisms in place for short term and long term insults on the cardiac system; the compensatory mechanisms will reveal little to nothing new at the level of heart rate or beat.

The other questions you posed about decreasing oxygen and carbon dioxide will be subjective at best without a thorough blood analysis. This will require a phlebotomist or a trained professional and a laboratory to handle this task.

You may want to consider different avenues related to the role of oxygen and carbon dioxide and set up an experimental question from there. For example, how is oxygen transported in the blood? How is it different than the way carbon dioxide is transported? If there is a difference, how do these differences become serious or important during breathing? Further, how does this affect heart rate? You can, with these basic questions, ask a lot more in depth questions and think of new ideas as well.

I hope this helps.

James

Nick S.
Posts: 2
Joined: Thu Oct 18, 2007 10:17 am

Thank you for your responses

Postby Nick S. » Sat Oct 20, 2007 12:01 pm

Dear Melisa B, Louise, Wil/z, James

Thank you for taking your time to answer my questions.

I have informed my parents about this project and I am giving them a print-out of your concerns for their review.

Once again, thank you for all your help.

Nick S

:shock:

Louise
Former Expert
Posts: 921
Joined: Mon Jan 16, 2006 2:17 pm

Re: Thank you for your responses

Postby Louise » Sun Oct 21, 2007 6:14 am

Nick S. wrote:Dear Melisa B, Louise, Wil/z, James

Thank you for taking your time to answer my questions.

I have informed my parents about this project and I am giving them a print-out of your concerns for their review.

Once again, thank you for all your help.

Nick S

:shock:


Nick! Glad to hear that you are consulting with your parents. If you do go ahead with this project, make sure to consult with your teacher too. Hope to hear about your project soon!

Louise


Return to “Life, Earth, and Social Sciences”