After exercising, a person becomes physically exhausted.  Does this physical exhaustion have an affect on mental exhaustion?  Researchers found that exercise stimulates the mind and produces adrenaline and noradrenaline, which alerts the brainŐs processing system (Jenkins 2007).  However, despite the chemicals released to help the brain react faster, scientists found that there is no significant difference in runnersŐ visual memory when resting and exercising (Sports Med 2007). Since visual memory was not affected by exercise, I thought that it occurred because the brainŐs reaction time had slowed down a little.  How an increase in the amount of exercise would affect the reaction time of the brain was the problem I tested.  The hypothesis was that if the heart rate affects the brainŐs reaction time, then the reaction time of the brain will increase as the heart rate increases.

            In order to test my hypothesis, I took three peopleŐs resting heart rates with a sphygmomanometer.  I then generated a random set of twenty colors using blue, green, white, and red.  The reaction timer was then used to test the amount of time it would take for a person to react to the set of colors.  Each person would then run until their heart rate was 40 beats per minute above their resting heart rate.  Another randomly generated set of colors was used to measure the amount of time it took for a person to react to the set of colors. 

            I used a T-test to measure if there was significant difference between the amount of reaction time before and after exercising.  The P-value was .09 (P>.05) based on the mean of the resting and post exercise reaction times, so there was not a significant difference between the reaction times.

            These results were inconsistent with my hypothesis.  As the heart rate increased, the reaction time slightly decreased.  The heart rate was measured inconsistently because the sphygmomanometer did not always show accurate heart rates.  Also, the heart rate was not consistent during the reaction time test, since the person was resting.  There were distractions in the classroom that may have had an affect on a personŐs reaction time. Other research has found that rock music slightly increased the reaction time, but music did not have a significant value in the brainŐs reaction time (Le 2006).  Our results were comparable since the brainŐs reaction time decreased when stimulated, but not by a significant amount. 

            Since increasing the heart rate by forty beats per minute decreased the reaction time, but not statistically significantly, the exercise should be longer, measured more consistently, and the trials should be isolated from distractions.  This should show a greater decrease in a personŐs reaction time.


Br J Sports Med., 2007.  Effects of Maximal Exercise on the Brain.  Peak Performance.  November 1, 2007:


Jenkins, Darlene, 2007.  The Brain-Body Connection: Can Exercise Really Make Our Brains Work Better?  Science Buddies.  November 1, 2007:


Le, Minh-Thy, 2006.  Exploring the ŇMozart EffectÓ and Reaction Time.  General Biology Lab I.  November 1, 2007: