Effects of Long Term Exercise on the Circulatory System

Danielle Fine and Julianne Fair

CU-Boulder, Fall 2007

 

The United States regularly receives criticism for the prominence of obesity, diabetes, hypertension, and other health related issues running rampant throughout the nation. Therefore, we chose the question, “Does exercise play a role in human healthy condiction?” 

When an individual exercises there is a higher demand for blood to reach the muscles resulting in increased blood flow.  An individual who exercises often needs more blood to be pumped to the muscles with every beat.  This led to our hypothesis: training an individual pursues will have an effect on blood pressure and peripheral resistance.  We then predicted that the more physically fit person will have the smaller the change in blood pressure before and after exercise and will have the lower peripheral resistance. 

In order to test our hypothesis, we gathered a group of thirty people ranging in the amount of exercise they engaged in per week.  We then measured their heart rates and blood pressures both before and immediately after one minute of jumping jacks. This information was then used to calculate blood pressure and total peripheral resistance. Converting blood pressure to mean arterial pressure (1/3 systolic plus 2/3 diastolic), made the values easier to compare.  We calculated peripheral resistance by: Mean Arterial Pressure = Stroke Volume (75 mL) x Heart Rate x Peripheral Resistance.

The results revealed a significant negative linear relationship between the time of participants’ physical fitness a week and mean arterial pressure. The data showed that as the number of hours of exercise per week increased, the change in mean arterial pressure decreased.  The significant F value was 2.33E-11 and the R square value was 0.80.

The second part of our results showed that peripheral resistance increased as the hours of exercise per week increased.  Again, the regression test showed significant F value of 4.39E-6 indicating the hours of exercise significantly impacted the total peripheral resistance.  The R square value (0.535) showed that the data did not adequately fit the linear regression line.  These results did not support our prediction that peripheral resistance would decrease as hours of exercise increased.

There were several problems with our experiment that potentially affected our results.  We had no means of accurately measuring stroke volume, so we assumed an average of 75 mL for every individual.  In actuality, stroke volume should increase for highly trained individuals (100-200 mL), decreasing peripheral resistance.  We believe this was the reason our data did not support our predictions.  Other problems in the experiment that were out of our control included: genetic variables (participant’s predisposition to hyper/hypotension), nutritional and sleeping habits, and the current mental state of the participant.  Despite these problems, other experiments similar to ours yielded results consistent to ours, regarding mean arterial pressure.

Our experiment raised other questions to potentially be tested in the future.  These questions include “How does exercise affect an individual who has chronic heart disease?” and “How does exercise effect an individual who is predisposed to hypertension or hypotension?”