Analyzing the Effect of Gender and Exercise on Pulse Count, Systolic Blood Pressure, and Diastolic Blood Pressure By: Christine Fanning 3/25/2014 TA: Yue Rui Biol 240W Section 009 Introduction Fanning 2014 There has been a lot more focus on cardiovascular health in the medical field lately. Chest pain centers are becoming more abundant and people are focusing more on changing their daily lives and life choices to improve their cardiovascular health. Some factors, such as sex of the individual and family history, are unable to be altered. For example, recent findings indicate that women are more likely to develop heart disease later in life than many men due to changes associated with menopause. Although some of these factors cannot be helped, research is showing doctors how to overcome these obstacles with methods such as hormone replacement therapy (Mendelsohn and Karas 2005). However, many choices such as smoking, exercise, and drinking habits, can be changed to reduce the stress on the individual’s cardiovascular system. Smoking is one choice that has gained media attention much more in recent years. Not only can smoking compromise longevity, but it can also cause everyday problems that a healthy, nonsmoker just does not need to worry about (Higgins et al. 1993). It can affect the individual as much as needing to walk slower because they can’t catch their breath or as little as not being able to pay attention in class because they are thinking about the next chance they will get to smoke. This experiment will focus on the differences in cardiovascular physiology following exercise between males and females and between people who exercise more than twice a week and people who exercise twice or less per week.. A person’s cardiovascular health can generally be measured by taking their blood pressure and heart rate. The blood pressure looks at a person’s systolic and diastolic pressure while the heart rate looks at the number of time their heart beats per unit of time, usually a minute. Blood pressure has both a high peak, systole, and low peak, diastole. Therefore, when taking blood pressure, a person is looking for a 15 Fanning 2014 systolic pressure and a diastolic pressure. These two numbers give an indication of how hard the heart is working to pump blood through an artery. A normal blood pressure is given at around 120 mm Hg for systolic and 80 mm Hg for diastolic. However, the numbers can vary widely from person to person. Exercise is one factor that can change a person’s pulse rate and blood pressure. With exercise, an increase in systolic blood pressure and pulse count can be expected. Diastolic blood pressure, however, is not normally expected to change very much and, in some cases, can lower after exercise (Kravitz 2000). However, in individuals who are not as healthy (those who smoke, drink, don’t exercise, etc.), the numbers should elevate more due to more stress on an already compromised cardiovascular system (Astrand et al. 1965). The goals of this experiment are to collect cardiovascular physiology data for each individual in the class and compare the values at rest to those obtained after exercise and to investigate cardiovascular fitness by correlating personal histories with individual cardiovascular parameters (Nelson and Burpee 2014). The hypothesis between the males and the females is that the blood pressure and pulse count will rise with exercise, more so for the 30 steps than the 15 steps per minute, but there will be no significant difference between males and females. However, for the comparison between those who exercised twice or less per week and those who exercised more than twice per week, the hypothesis is that the group that exercised less will have a greater increase in numbers after exercise than the numbers for the group that exercised more. Materials and Methods The experiment required two major steps. The first was data collection, and the second was data analysis. These steps were divided over three weeks. 15 Fanning 2014 Data Collection The first week consisted of collecting personal, background data for each of the participants. This data included age, gender, weight, and smoking, drinking, and exercise habits. For the second week, the first step was to acquire resting data. Each individual took their pulse count, using their radial artery on their wrist, for thirty seconds and recorded it. This was done 3 times and the counts were averaged. The average was the pulse count that was recorded for the resting data. Each individual’s resting systolic and diastolic pressure was then measured using a sphygmomanometer and stethoscope. Next, each group was given a step and each individual spent a minute stepping up and down with a beat at sixty beats per minute on a metronome. The person then sat down for fifteen seconds and the pulse count, systolic, and diastolic pressure was measured and recorded. The same was then repeated at 120 beats per minute. After the exercise, we had resting and exercise data for both 15 and 30 steps per minute. Data Analysis The next step after collecting all of the data was to analyze it. This involved finding the averages and the standard deviations for the resting pulse count, systolic, and diastolic pressure. The standard deviation was then used to calculate the standard error, Equation 1. Equation 1: Standard error = Standard Deviation / sqrt(number of individuals) Example using female resting pulse count: SE = 5.895/ sqrt(39) =0.9440 The percent difference between the data after exercise and the resting data was then calculated for both the 15 step data and the 30 step data using Equation 2. 15 Fanning 2014 Equation 2: Percent Difference=(count after exercise-­‐resting count)/resting count*100 Example using female pulse count for 15 steps: %diff= (38-­‐35)/35*100 =8.57 The percent differences were then averaged to come up with an average percent difference for 15 and 30 step for pulse count, systolic pressure, and diastolic pressure. A t-­‐test was then performed for each data set (average counts, average percent differences, etc.) between each population to determine if there was a significant difference between the two populations. The previous procedure for data analysis was carried out for two separate population comparisons; males and females and people who exercise more than twice a week and people who exercise twice or less per week. Results The results from the data collection were arranged in tables as shown below and then plotted in graphs to show comparisons between the two genders. Table 1 shows the resting data that was then used to compare with the exercise data. Males
average
Pulse
count
Sys.BP
Dias.BP
38.12
116.75
73.3
SE
Females
Average
SE
1.369606167
1.865017285
2.56299578
38.27089744
114.6410256
69.84615385
0.99316629
1.401987783
1.866509462
Table 1: Resting Averages and Standard Errors for Males and Females The following tables are averages from the data collected fifteen seconds after exercise. 15 Fanning 2014 Males
Pulse
count
15steps
30steps
Females
av.% diff
SE
av.% diff
SE
20.64632132
6.378260727
32.00462117
2.947659674
48.42247532
8.651835768
44.6289491
3.531911321
Table 2: Normalized Average Change in Pulse Count After Exercise for Males and Females There is already a larger percent difference, even if only barely, in pulse count for both 15 steps per minute and 30 steps per minute for males than there is for females. The same general trend is seen in systolic blood pressure average percent differences in Table 3. Males
Systolic
BP
15steps
30steps
Females
av.% diff
SE
av.% diff
SE
9.249115544
1.865570494
7.700995508
1.450045531
18.95436312
2.767428238
16.89695805
2.280197564
Table 3: Normalized Average Change in Systolic Blood Pressure After Exercise for Males and Females However, the changes in diastolic blood pressure do not appear to follow a specific trend. The females had a greater percent difference for the 15 steps per minute, but the males had a much greater change after the 30 steps per minute. Males
Diastolic
BP
15steps
Females
av.% diff
SE
av.% diff
SE
6.033276552
5.175342251
6.868643075
3.655800808
Table 4: Normalized Average Change in Diastolic Blood Pressure After Exercise for Males and Females 15 Fanning 2014 30steps
13.89132609
5.633041269
7.958811402
3.651231976
The trends are better observed when the data is put into graphs, as shown below. Measurement (beats/mmHg) Resting Data for Males and Females 140 120 100 80 Males 60 Females 40 20 0 Pulse count Sys.BP Dias.BP Figure 1: Resting Data with Standard Errors for Males and Females. Pulse Counts are measured in beats per 30 seconds and systolic BP and diastolic BP are measured in mm Hg. Average Percent Difference Average Percent Differences After 15 Steps/Minute 30 25 20 15 Male 15-­‐step 10 Female 15-­‐step 5 0 Pulse Count Systolic BP Diastolic BP Figure 2: Average Percent Differences with Standard Errors between males and females after exercise. The exercise was stepping up and down on a box to a metronome for a total of 15 steps per minute. 15 Fanning 2014 Average Percent Difference Average Percent Differences After 30 Steps/Minute 60 50 40 30 Male 30-­‐step 20 Female 30-­‐step 10 0 Pulse Count Systolic BP Diastolic BP Figure 3: Average Percent Differences with Standard Errors for males and females after exercise. The exercise was stepping up and down on a medium sized box for a Resting
0.9294
Pulse Count
15-steps
0.1714
30-steps
0.6882
Systolic Blood Pressure
Resting
15-steps
30-steps
0.3714
0.5158
0.5691
Diastolic Blood Pressure
Resting
15-steps
30-steps
0.2827
0.8958
0.3828
Table 5: Results of the T-­‐test between men and women of the normalized differences between resting and exercise data. total of 30 steps per minute. The same procedure of analyzing data was then repeated, but the second two populations that were compared were people who reported that they exercised more than twice a week and people who reported that they exercised twice or fewer times per week. The data was then grouped in charts shown below. Exercised ≤ 2 days
Pulse count
Sys.BP
Dias.BP
average
38.73823529
114.6470588
70.82352941
Exercised > 2 days
SE
1.328958636
2.281545491
2.74697065
Average
38.00988095
115.6428571
71.0952381
SE
0.990113593
1.290014103
1.829494299
15 Fanning 2014 Table 6: Resting Averages and Standard Errors for those who exercised twice or less per week and those who exercised more than twice per week The numbers for the averages are extremely close for the resting data. The biggest difference is by about 1. However, the standard errors for the ≤ 2 days group are consistently larger than those for the > 2 days group. Exercised ≤ 2 days
Pulse
count
15steps
30steps
Exercised > 2 days
av.% diff
SE
av.% diff
SE
20.14758383
7.060410417
11.6700699
2.996518875
53.1769299
8.857462731
42.97549316
3.773713244
Table 7: Normalized Average Change in Pulse Count After Exercise for those who exercised twice or less per week and those who exercised more than twice per week. There appears to be consistently higher numbers for the ≤ 2 days group than for the >2 days group. Not only is the average change in pulse count higher for both 15 steps per minute and 30 steps per minute, but the standard errors are also larger for the ≤ 2 days group. The same trend is seen in the average differences in systolic blood pressure Exercised ≤ 2 days
Systolic
BP
15steps
30steps
Table 8: Exercised > 2 days
av.% diff
SE
av.% diff
SE
9.513950954
2.445727682
7.704380226
1.275995982
22.01050598
3.607941003
15.80690535
1.967387499
Exercised ≤ 2 days
Exercised > 2 days
Normalized Average Change in Systolic Blood Pressure After Exercise for those who exercised twice or less per week and those who exercised more than twice per week 15 Fanning 2014 Diastolic
BP
15steps
30steps
av.% diff
SE
av.% diff
SE
1.44793791
4.396971716
8.66494444
3.741422071
9.008678316
5.023135291
10.35887227
3.840252682
Although both the pulse count and the systolic pressure differences showed a very similar trend, the change in diastolic blood pressure shows the opposite trend. The standard errors for the ≤ 2 days group are still consistently higher than for the > 2 days group, but the average percent differences are higher for those who exercised more than for the more infrequent exercisers when comparing the data for diastolic blood pressure. As with the data for males compared to females, the data comparing exercise groups was then put into graphs. Measurment (Beats/mmHg) Resting Data For the Exercise Groups 140 120 100 Exercised Twice or Less 80 60 Exercised More Than Twice 40 20 0 Pulse count Sys.BP Dias.BP Figure 4: Resting data with standard error bars for those who exercised twice or less per week and those exercised more than twice per week. The pulse counts are measured in beats per 30 seconds and the systolic and diastolic pressures are measured in mm Hg. Table 9: Normalized Average Change in Diastolic Blood Pressure After Exercise for those who exercised twice or less per week and those who exercised more than twice per week 15 Fanning 2014 Average Percent Difference Average Percent Differences After 15 Steps/Minute 30 25 20 Exercised Twice or Less 15 10 Exercised More Than Twice 5 0 -­‐5 Pulse Count Systolic BP Diastolic BP Figure 5:Average Percent Differences, after exercise, with standard error bars for those who exercised twice or less per week and those who exercised more than twice per week. The exercise performed involved stepping up and down on a medium sized box for a minute at 15 steps per minute. The data was collected 15 seconds after exercise. Average Percent Difference Average Percent Differences After 30 Steps/Minute 70 60 50 Exercised Twice or Less 40 30 Exercised More Than Twice 20 10 0 Pulse Count Systolic BP Diastolic BP Figure 6: Average percent differences, after exercise, with standard error bars for those who exercised twice or less per week and those who exercised more than twice per week. The exercise performed involved stepping up and down on a medium sized box for a minute at 30 steps per minute. The data was collected 15 seconds after exercise. 15 Fanning 2014 Pulse Count
Resting
15-steps
0.6630
0.2809
30-steps
0.3008
Systolic Blood Pressure
Resting
15-steps
0.7069
0.5177
30-steps
0.1431
Diastolic Blood Pressure
Resting
15-steps
30-steps
0.9349
0.2186
0.8321
Table 10: Results of a T-­‐test between those who exercised twice or less per week and those who exercised more than twice per week of the normalized differences between resting and exercise data. The threshold for a significant difference was 0.05. There were no significant differences between the two exercise groups, according to the t-­‐test. Each probability generated from the t-­‐test was above 0.05 and, therefore, not statistically significant. Discussion Although there were definite trends that the data followed, the t-­‐test did not show any significant differences for either comparison of experimental groups. However, for the males compared to females, the males consistently had higher average changes for both pulse count and systolic pressure after exercise. Although not significant by the t-­‐test, it does show that there was moderately higher stress on the males after exercise than for females and that the males cardiovascular systems were working harder. However, this result could also be due to extraneous factors such as weight since males generally weigh more than females. Therefore, the hypothesis was correct in saying that there would be no significant difference between the males’ and females’ changes in cardiovascular physiology after exercise. The only disagreement with the hypothesis was the diastolic blood pressure changes, which did not show any trend. The average change was lower in males after 15 steps, but higher in males after 30 steps. This could be due to experimental error. The individuals who were taking pulse count were just counting and using a timer, which left little room for too much error. However, those taking 15 Fanning 2014 systolic and diastolic blood pressure were having a difficult time using the sphygmomanometer and hearing the correct sounds through the stethoscope. Therefore, there can really be no definite conclusion drawn when comparing males and females for the diastolic blood pressure. There were similar results seen in the comparison of people who exercised more than twice a week (exercisers) to people who exercised twice or fewer time per week (non-­‐exercisers). There was a consistently higher change in pulse count and systolic blood pressure for non-­‐exercisers after exercise than for exercisers. The diastolic pressure, however, followed the exact opposite trend and showed a consistently higher average change for exercisers after exercise than for non-­‐exercisers. Once again, however, the t-­‐test did not show the difference in the results to be statistically significant across the two groups. The hypothesis for this comparison was partially supported by the data. The exercisers did generally have less of an increase in numbers than the non-­‐exercisers. The only deviance from the hypothesis was, again, the diastolic pressure. However, the diastolic pressure is not supposed to change much with exercise and has been seen to show a trend of decreasing with exercise due to vasodilatation after exercise (Kravitz 2000). Therefore, the decrease in diastolic pressure in the non-­‐
exercisers could be due to the need for their arteries to dilate more than the exercisers to keep up with the requirement for a fresh blood supply for a cardiovascular system that is not used to frequent stress. A source of error could be a discrepancy between the number of days that an individual reported working out and the number of days they actually did work out. This would skew the results in a number of ways. Further experiments could be done by following certain people for a few weeks and recording 15 Fanning 2014 their workouts and then repeating the same procedure. This would give more accurate results. Further experiments for the entire experiment could involve a comparison of two difference populations from the background data or a completely different measurement, such as lung capacity. The same experiment could be done with a larger number of individuals for a much more accurate result. Either way, the results are important in giving insight into better ways of living and keeping up a healthy cardiovascular system. 15 Fanning 2014 References Astrand, P., Ekblom, B., Messin, R., Saltin, B., Stenberg, J. (1965). Intra-­‐arterial Blood Pressure During Exercise with Different Muscle Groups. Journal of Applied Physiology 20(2) 253-­‐256 “Cardiovascular Physiology: The Relationship between Gas Exchange and Cardiac Activity.” Edited by Nelson, K. and Burpee, D. Department of Biology, The Pennsylvania State University, University Park, PA. (2014) Higgins, M.W., Enright, P.L., Kronmal, R.A., Schenker, M.B., Anton-­‐Culver, H., Lyles, M., Gregory, B., Cruise, R.G., et al. (1993) Smoking and Lung Function in Elderly Men and Women. The Journal of the American Medical Association 269(21) 2741-­‐2748 Kravitz, L. (2000) Exercise and Resting Blood Pressure. The University of New Mexico. Mendelsohn, M.E., Karas, R.H.(2005) Molecular and Cellular Basis of Cardiovascular Gender Differences. Science 308(5728), 1583-­‐1587 15