Science Buddies: "Ask an Expert"

I did a project two years ago about circadian rhythms that I based on a project on this site: https://www.sciencebuddies.org/science- ... ml#summary. I found that body temperature is lower earlier in the day and higher later in the day and vice versa for reaction time. I was thinking of expanding on my old project this year, but I'm not sure what to do.

Very interesting topic. There are lots of bodily functions that show circadian changes but finding ones that you can measure is important.

Personally I think brain rhythms are one of the most interesting areas of study. Sleeping and waking brain waves are very different. When you are awake your brain usually generates beta waves that are associated with talking, reading, listening and physical activity (http://web.mst.edu/~psyworld/sleep_stages.htm). But can a person see their brain wave patterns without complicated, expensive equipment? The answer is yes--there is an app for that.

I read a paper about a smart phone app that uses a brain wave headset to monitor brain activity but I don't know if it is available yet (http://journals.plos.org/plosone/articl ... ne.0086733). Here's another reference to the same device: http://sciencenordic.com/your-smartphon ... your-brain

I know you can buy the headsets that let you see your brain activity in real time: https://www.google.com/search?q=smart+p ... t&tbm=shop

I don't have one of these units and I have no idea which ones are good. They vary a lot in price, so if you really want to try this it would be worth comparing prices on Amazon, eBay, etc.

There have been some studies showing health benefits associated with increases in alpha waves which can occur during meditation and deep relaxation (https://www.psychologytoday.com/blog/th ... depression). Athletic performance, creativity and mental activity are all enhanced when alpha waves are present. If you could see your brain waves like you do heart rate and blood pressure on your fitbit, maybe you could increase the alpha waves and achieve better brain performance.

I think you could build a good science project around measuring brain waves under various conditions--relaxing with fave music, after drinking coffee or soda with sugar, preparing for a test (uggh!), after working out, while driving, etc. You would want to have a headset that could record the EEG trace over a certain time interval so you could download it later and analyze it in relation to what the subject was doing at the time.

I hope this gives you some ideas about circadian rhythms to use for a science project. Brain activity and behavior are so intimately connected that I think looking at how they are correlated is really cool. Other people on this forum can give you some other ideas for biorhythms to measure.

Good luck!

Sybee

I looked at the prices for eeg headsets, and it looks like they're too expensive for me to use in my project. I was actually interested in incorporating my project from two years ago about body temperature and reaction time and how they vary throughout the day. I found that body temperature is the lowest in the early morning and the highest in the early evening and reaction time is slower in the morning and faster in the evening. I was thinking that I could do an experiment on how performance is affected by changes in body temperature and reaction time. For example, since reaction time is faster in the evening, maybe i could see if exercise is enhanced when reaction time is faster. I could also test to see if exercise is enhanced when body temperature is lower/higher. Do these ideas sound good? I would appreciate any other ideas for expanding my old project.
Thanks for your time!

OK, but I have a lot of questions about your methods since I don't know what you did in your previous project. What was your hypothesis then and what is it now? How are you measuring your subject's temperature? I read the wiki on body temperature (https://en.wikipedia.org/wiki/Human_body_temperature) and there is a lot of variation in what is considered 'normal'. Also, there are several ways to measure body temperature that all give slightly different values.

As soon as a person starts exercising hard, their skin temperature is going to rise due to the increased blood flow. Have you considered the effect of skin temperature changes vs core temperature changes on performance? What about the temperature of the air where the subject is exercising? Where i work out it is quite cool and if it was hot i would not be able to do as well.

You said you will measure 'performance'. What sort of performance? What will you measure and how? How will you insure that each of your subjects 'performs' in the same way each time? What about the differences caused by age, gender, BMI and general fitness level? How many subjects will you have in your trial? You need to do a statistical sample size test to determine how many subjects are needed otherwise your results will be meaningless.

Experiments with people are difficult because of the large number of potential variables. We can try to help you improve the statistical accuracy of the results if you will give us more details about your methods, the number of subjects and whether you selected them according to age, fitness level, gender, current state of wellness, etc.

Let us know your hypothesis and methods and maybe we can make some helpful suggestions.

Good luck!

Sybee

Hi,
My original question was: how do body temperature and reaction time vary throughout a day? My hypothesis was that body temperature Is lower earlier in the day and higher later in the day and reaction time is slower earlier in the day and faster later in the day. I measured my subjects body temperature by having them record their body temperature at various times throughout the day (starting at 5 am and every three hours until 8 pm). I had them measure their body temperature orally using the same thermometer (I had them use various thermometers when I started the experiment, but had them stop because the results were only about .1 degrees off). I instructed my subject not to exercisize, go outside (it was winter), or drink hot/cold beverages before measuring their body temperature, and I also had them record their measurements in the same room.
I was thinking of having my subjects exercise using a treadmill and recording their reaction time and body temperature before their workout. When I said performance, I meant that I would record the amount of time to exhaustion Of course I would have to consider fitness ability, weight/bmi, age, and gender, like you mentioned. The people I plan on using for my experiment are actually around the same age as me (13/14), are all girls, and, as far as I know, are at the same level in fitness ability. I don't think their weights will be an issue, since they are all normal, and they are all healthy and have no pre-existing medical conditions.
Thanks for your time!

Hi,
It looks like you have everything pretty much under control but I still have a couple of concerns.

You said your experimental endpoint was 'time to exhaustion' correct? I'm not a fitness expert but I do run on a treadmill and monitor my heart rate as well as lift weights. How are you defining exhaustion? When someone decides that they just can't run any longer? That's pretty vague. Some people have better endurance and tolerance for the feelings of fatigue. When I lift weights it is pretty easy to tell when the muscles are exhausted because i can't lift any more.

All I am trying to say is that testing a hypothesis requires an objective measurement--something like body temperature or heart rate--that is not reported by the subject. Telling your subjects to stop when they are 'exhausted' just seems too imprecise to me. Maybe it can work if there are large differences in your subjects' endurance depending on initial body temperature but I don't think that is the case.

Here's a good paper on exercise and fatigue that explains just how complicated the bodily factors are in relation to the mental perception of 'exhaustion': http://www.ncbi.nlm.nih.gov/pubmed/19402743
Sports Med. 2009;39(5):389-422. doi: 10.2165/00007256-200939050-00005.
Exercise and fatigue.
Ament W1, Verkerke GJ.

And here's a website on the more practical aspects of fatigue and exercise in the gym: http://www.bodybuilding.com/fun/md32.htm

Are your subjects using a heart-rate monitor during the test? I would strongly advise that they do. Record their basal bpm, then time to target bpm which will depend on what intensity of exercise you have chosen. I would think that you should keep the target at about 70% of maximum heart rate.

Record bpm when the subjects stop exercising and then the time to return to normal heart rate. I think these quantitative measurements will add to the strength of your conclusions.

One last thing--sample size. There are statistical methods that allow you to calculate how many subjects you need to get meaningful data at 95% confidence. If you have some knowledge of statistics you can look up how to do this on Google or youtube, otherwise just try to get the most subjects possible. You should always describe your statistical analysis in your project report as this is the only way that you can actually prove or disprove the hypothesis.

Sorry to be so long-winded about this. I just want to make sure that your project is successful. Let us know if you have more questions.

Good luck!

Sybee