Expert: Daniel Mazur - 9/18/2005

Question
Hi,
I am thinking of doing a science fair project on stress. Do you know how I can measure a person's stress level. I was going to do a topic like

Does the amount of sleep a person gets affect their stress level?

Thank you very much.  

Answer
Hi Kevin,

there are undoubtedly a few approaches to measuring stress of a living entity. I don't feel an expert in this field as this is an area of psychology and psychiatry (to uniquely define "stress") and medicine plus biophysics. Nevertheless, I'll try to give some general advice on, how to pick the physical quantities to observe and to determine the "quantity-to-stress" conversion relation.

The "Lie Detector" for example, is in fact a stress detector, which uses the heartbeat, blood pressure and skin conductivity (and maybe other quantities) readings to determine a "lie" - a statement accompanied by an increase in stress symptomes. Now, the stress symptomes can be misinterpreted and therefore the reliability of a lie detector cannot be 100%. However, its readings can be quite reliably interpreted in terms of stress level.

The first thing to do for your project is to find (or make) a nice definition of stress. Second, consider your material resources to decide, what physical quantity you are going to measure. Almost every measurable quantity in humans changes under stress, so you need to pick one that you can measure conveniently, with low cost and reliable results. If several ones meet these criteria, you should pick one that will have the best results-to-effort ratio. A good way to go (one that I would choose) is to search libraries and the internet on information, how to "calibrate" each method. Should you have plenty of time, you could just do the calibration yourself (series of experiments on a plenty of people with different levels of stress), but I do not think this will be the case. If nothing else, it's hard to get a reasonably large "statistical set" of people for a science fair. Therefore, getting somebody else's results of a similar experiment will be an important point to start with. Chances are that all you need is a couple of cables with skin-contact electrodes, an omh-meter and an XY-plotter and you'll be fine. When you get to this point, you can spend the remaining time to make it look fancier (a computer gets in the game:-)).

To sum up, the general advice is to search psychiatry and biophysics journals plus a few popular resources on the subject of measuring stress on humans. Should you feel there is need for an expensive equipment for one method, either look for ways to make it cheaper (even if less accurate) or pick a different physical quantity to measure.

I apologize I cannot help you more than this. Still I hope you find this response useful. Please don't hesitate to rate it here at AllExperts.com.

Good Luck!
Daniel