Study of Exercise on heart rate
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Transcript of Study of Exercise on heart rate
ABSTRACT:
The autonomous nervous system controls one’s heart rate and blood pressure. This can be
affected by gravity, exercise, temperature and submergence. These factors were all varied and
observed in this experiment.
Male and female subjects were then subjected to various tests, each varying a different variable
factor. The results of altering these variables were recorded and results contrasted between
males and females. It is postulated that these variables alter the heart rate and blood pressure
in some discernible way.
Due to the vast differences in the class data set. Observed results were anomalous and
discernible trends difficult to analyse.
INTRODUCTION:
The autonomous nervous system controls involuntary processes within the body, such as the
heart rate and blood pressure. It is part of the peripheral nervous system. Due to external
pressures from the environment, [gravity or temperature] or changes in the body’s
requirements under stressful conditions can lead to a change in these processes.
Blood, in our circulatory system, exerts pressure on the walls of the blood vessels as it traverses
through them about the body via systemic circulation. This pressure can be measured using a
sphygmomanometer. The units of measurement for blood pressure are millimetres of Mercury
[mmHg], written as systolic blood pressure over diastolic blood pressure. Normal blood
pressure is considered to be 120/80 mmHg.
Within the heart there are 4 chambers, the left and right atrium, and the left and right ventricle.
Blood, on entering the atrium contracts and pushes blood into the ventricles. The ventricles are
larger compared to the atria of the heart. This pumping action of the heart is known as the
cardiac cycle and in this cycle there are two phases, the systole and the diastole. Systolic
pressure is the pressure received by the arteries from the contraction of the ventricles during a
heartbeat, whereas diastolic pressure is the pressure exerted by the blood in the arteries in-
between heart beats while the muscle relaxes.
The systolic phase is coincided with contraction of the hear muscles. This occurs when
deoxygenated blood enters the right atrium which contracts, pushing the blood into the right
ventricle. The right ventricle then contracts to push the deoxygenated blood to the lungs to be
oxygenated. The blood which has been oxygenated then eneters the left atrium which
contracts, forcing the blood into the left ventricle. From the left ventricle, via contraction the
blood is then pushed throughout the body.
Diastolic pressure is the minimal pressure exerted by the blood on the arteries during relaxation
of the ventricles as they fill up with blood
An electrocardiogram [ECG] is a test used which functions by recording the electrochemical
activity of the heart as it beats. The ECG illustrates the rhythm of the heartbeat, the strength
and timing of the electric signals as they pass through the heart and also how fast the heart is
beating.
Figure 1 : Example of a Normal ECG (Practical Clinical Skills, 2013)
The ECG gives a chart of peaks which correspond to the different stages of the cardiac cycle.
The P wave symbolizes the atrial depolarization; the PQ segment represents the atrial systole.
The QRS complex shows the ventricular depolarization whilst the ventricular systole is given by
the ST segment. The T wave illustrates ventricular repolarization.
Figure 2 : ECG Waves, Intervals and Segments (Chest, Heart and Stroke Scotland, 2014)
The pulse pressure is deduced by the stroke volume of the heart, the expansive ability of the
arterial system due to the aorta other large arteries and the resistance of flow in the arteries.
The elasticity of the arteries aid in the reduction of the blood pressure hence reducing the pulse
pressure. . Pulse pressure is derived from the blood pressure readings. Higher blood pressure
gives rise to a stronger pulse and vice versa. Thus pulse pressure if proportional to blood
pressure.
Pulse Pressure = Diastolic pressure – Systolic Pressure
The body responds to vasoconstrictions in the extremities when exposed to cold stress to
maintain the core temperature. This alter blood pressure. This is tested using the cold pressor
test in which the subjects hand is immersed in ice water for a certain period of time before
pulse rate and blood pressure are measured.
Gravity affects blood flow distribution depending on one’s positioning. When laying down,
blood flow is even from the base to the apex i.e. feet to head. Gravity gives rise to uneven
pulmonary blood flow in an upright person. Due to the downward pull of gravity, a lower blood
pressure is seen at the apex of one’s lungs.
Exercising has tendencies to offset the gravitational effects in an upright person. With exercise,
ventilation is increased as the oxygen demands of the body are greater than before in the
resting state. More oxygen is needed to respire as the body requires more energy. Thus heart
rate and blood pressure rise in order to facilitate the heightened requirements of the body.
When the body is submerged underwater, when one is holding their breath, the body enters a
state of oxygen conservation known as the mammalian diving reflex. To stimulate this effect,
subjects were required to hold their breath. This affects both the blood pressure and heart rate.
Body mass index [BMI] is utilized to determine how much fat a person has. This is also in
indicator of one’s health i.e. if one is underweight, healthy, overweight or obese.
BMI=weight (¿kilograms)height (¿metres)2
.
A BMI value of less than 18.5 is considered “underweight”, 18.5 to 24.9 is considered “normal”,
25.0 to 29.9 is considered “overweight” and values of over 30 are considered “obese” (Castro,
2013).
This experiment seeks to gain insight into the effects of the variable factors of gravity,
temperature, submergence and exercise on blood pressure and pulse by altering each factor
one at a time and observing the changes in data.
METHOD:
The radial pulse of the individual to be tested was taken by feeling their pulse with the palm
facing upward and feeling for the beating sensation with the index and middle fingers. The
number of beats in 15s was recorded and converted into beats per minute [BPM]. The height
and weight of the subject was also recorded.
The subject was placed in a seated position and the left arm placed upon the lab bench. The
sphygmomanometer was placed on the upper arm ensuring that the arrow was above the
brachial artery. The cuff was inflated until it did not fall and then with the stethoscope on, the
diaphragm placed on the antecubital space. The cuff was then inflated to 150 mmHg and the
valve on the runner ball opened slightly whilst listening for pressure sounds. The pressure at
which the sounds were detected were recorded the systolic pressure. The valve was then
opened further and the pressure at which the sounds disappeared taken as the diastolic
pressure. These sounds are referred to as the Korotkoff noises.
The blood pressure and heart rate were then determined while the subject stood quietly, and
after running in place for 1, 3 and 5 minutes. Then with the subject seated, the resting blood
pressure and heart rate were recorded. The subject then held his/her breath as long as
possible. The heart rate was measured whilst the subject held their breath. Once breathing was
resumed, readings for heart rate and blood pressure were taken at 1 minute intervals for five
minutes.
The subject was then laid back, in a lying position and the heart rate and blood pressure
recorded. This was also done for the subject in a seated position and a standing position.
With the subject seated comfortably, the heart rate and systolic and diastolic pressures were
recorded. Their free hand was submerged in ice water to a depth above the wrist. The hand
was rapidly removed from the ice bath and dried. The blood pressure and heart rate were then
recorded on the opposite arm. This was repeated at one minute intervals until the heart rate
and blood pressure returned to control values.
A fully annotated ECG was then done for a male and female subject in the normal resting state
using standard limb leads. Then immersing the palm in cold water, another ECG was done
ensuring the leads did not get wet. The subjects then underwent vigorous exercise for 5
minutes before producing another ECG chart.
RESULTS:
Table 1. Summarization of Male individuals tested
Subject
MALE Height: Weight Ratio cm/kg
BMI STATUSHeight/ cm
Weight/ kg
1 187 97 1.9 27.7 Overweight2 160 74 2.2 28.9 Overweight3 170.4 61 2.8 21.0 Normal4 181 75 2.4 22.9 Normal5 172 65 2.6 22.0 Normal6 194 79 2.5 21.0 Normal7 195 97 2.0 25.5 Overweight8 174 51 3.4 16.8 Underweight9 176 77.2 2.3 24.9 Normal
10 168 62 2.7 22.0 Normal11 182.5 93 2.0 27.9 Overweight
Table 2. Summarization of Female individuals tested
Subject
FEMALE Height: Weight Ratio cm/kg
BMI STATUSHeight/ cm
Weight/ kg
1 157 50 3.1 20.3 Normal2 156 82 1.9 33.7 Overweight3 162 56 2.9 21.3 Normal4 162 56 2.9 21.3 Normal5 149 30 5.0 13.5 Underweight
Table 3. Summary Table of Average Male and Female Blood pressure and Heart Rate in their respective catergories.
CLASS INTERVAL
MALE FEMALEAVERAGE
HEART RATE
AVERAGE BLOOD PRESSURE
AVERAGE HEART RATE
AVERAGE BLOOD PRESSURE
SYSTOLIC DIASTOLIC SYSTOLIC DIASTOLICUNDERWEIGHT 64 12 22 96 108 68
NORMAL 65.3 107 74 81.3 111.3 76OVERWEIGHT 81 126.25 90 80 130 105
UNDERWEIGHT NORMAL OVERWEIGHT0
20
40
60
80
100
120
140
Resting Systolic Blood Pressure of Males vs Females
SYSTOLIC MALE SYSTOLIC FEMALE
The figure above illustrates the systolic blood pressure of males and females in the resting state. Both the Normal and Overweight categories are quite similar with the males being just a slight bit less than the females. With the underweight category, with males there was only one person which gave a very low reading which most likely is anomalous. Also being only one underweight female in the data set, the systolic value read may also be anomalous.
UNDERWEIGHT NORMAL OVERWEIGHT0
20
40
60
80
100
120
Resting Diastolic Blood Pressure of Male vs Female
DIASTOLIC MALE DIASTOLIC FEMALE
The trend in the resting diastolic pressure shows females having higher values than the males
across all categories. Due to the Underweight category having only one male and female, the
readings may be inaccurate.
UNDERWEIGHT NORMAL OVERWEIGHT0
20
40
60
80
100
120
Average Heart Rate of Male vs Female
HR MALE HR FEMALE
The resting heart rate of the males and females in the overweight category are quite similar and
almost equal. The underweight and normal categories of males have almost equal heart rates
as well. The females in the underweight and normal categories however had higher values than
the males.
S t an d i n g Qu et l y
I mm
ed i a t e l y After
1 mi n u t e aft er
3 mi n u t es aft er
5 mi n u t es aft er
0
20
40
60
80
100
120
140
Eff ect of Exercise on Heart rate in MalesUnderweight Normal Overweight
The trend of these results with the effect of exercise on heart rate across the categories of male
subjects in the calls data are quite similar. The heat rate increases initially during and after
exercise before slowly returning back to the resting state with time. The overweight category
followed the trend however, had a higher heart rate that both the normal and underweight
male categories.
S t a n d i n g Q u et l y
I m m ed i a t e l y A ft er
1 m i n u t e a ft e r
3 m i n u t es a ft er
5 m i n u t es a ft er0
20
40
60
80
100
120
140
160
Eff ect of Exercise on Heart Rate in FemalesUnderweight Normal Overweight
With the female categories, similar trends with heart rate were seen as compared to the males.
However, the overweight and underweight categories had very similar rates of increase and
decrease of heart rate with time with a fast decrease back to resting heart rate. The normal
category however, even though following the general trend, returned to resting heart rate at a
slower rate.
S t a n d i n g Q u i e t l y
I m m ed i a t e l y A ft er E x er c i s e
1 m i n u t e a ft e r e x er c i s e
3 m i n u t es a ft er ex er c i s e
5 m i n u t es a ft er ex er c i s e0
20
40
60
80
100
120
140
160
Eff ect of Exercise on Systolic BP [M]UnderWeight Normal Overweight
The systolic pressure across the three categories in males all followed the same trend.
Overweight males showed a higher systolic pressure as compare to the normal and
underweight males. Normal males showed very little variation in systolic pressure as compared
to the underweight and overweight males with the effect of exercise.
S t a n d i n g Q u i e t l y
I m m ed i a t e l y A ft er E x er c i s e
1 m i n u t e a ft e r e x er c i s e
3 m i n u t es a ft er ex er c i s e
5 m i n u t es a ft er ex er c i s e0
20
40
60
80
100
120
Eff ect of Exercise on Diastolic BP [M]UnderWeight Normal Overweight
All categories here showed the same general trend with regards to the fluctuations of diastolic
pressure with time after exercise. The males which were classed as normal showed the least
fluctuation whilst those who were underweight showed the most.
S t a n d i n g Q u i e t l y
I m m ed i a t e l y a ft er ex er c i s e
1 m i n a ft e r e x er c i s e
3 m i n u t es a ft er ex er c i s e
5 m i n u t es a ft er ex er c i s e0
20
40
60
80
100
120
140
Eff ect of Exercise on Systolic BP [F]Underweight Normal Overweight
All categories of females followed the general trend in change of systolic pressure with exercise
and recovery. However, the overweight category of females showed the least fluctuation in the
systolic pressure and stayed almost constant throughout the recovery period.
S t a n d i n g Q u i e t l y
I m m ed i a t e l y a ft er ex er c i s e
1 m i n a ft e r e x er c i s e
3 m i n u t es a ft er ex er c i s e
5 m i n u t es a ft er ex er c i s e0
20
40
60
80
100
120
Eff ect of Exercise on Diastolic BP [F]Underweight Normal Overweight
All females in the data set followed the general trend in fluctuation of diastolic pressure with
exercise and recovery time. However, the normal and underweight categories of females
showed the least variation in the diastolic pressure with exercise and recovery time.
Table 4. ECG Calculations for Male subject
SEX: MALE Weight: 162 lBS Height: 182cm
Duration Amplitude
ActivityP
wave
PR-segme
nt
QRS-wave
ST-segme
nt
T-wave
Heart rate/bp
m
Pwave QRS T
Normal resting
.06 .08 .12 .04 2.0 68 0.5 0.1 ---
Immediately after exercise
.08 .08 .04 .04 .16 136 --- 0.4 ---
1 min after exercise
.08 .08 .04 .12 .12 125 --- 0.3 ---
3 min after exercise
.08 .08 .04 .04 .20 125 --- 0.6 ---
5 min after exercise
.06 .12 .04 .04 .12 125 0.2 0.5 ---
8 min after exercise
.04 .08 .04 .08 .12 115 --- 0.5 ---
Immediately after
cold press.06 .08 .05 .10 .12 125 0.15 0.4 0.3
1 min after cold press
.04 .08 .04 .08 .18 125 --- 0.4 ---
3 min after cold press
.06 .12 .04 .08 .10 107 0.1 0.2 0.3
5 min after cold press
.04 .12 .04 .08 .12 115 --- 0.2 ---
8 min after cold press
.08 .10 .04 .04 .12 107 --- 0.2 ---
Table 5. ECG Calculations for Female Subject
Sex: Female Weight: 146 lBS Height: 166.5
Duration Amplitude
ActivityP
wave
PR-segme
nt
QRS-wave
ST-segme
nt
T-wave
Heart rate/bp
m
Pwave QRS T
Normal resting
.08 .04 .06 .16 .12 83 0.1 0.4 0.2
Immediately after exercise
.04 .06 .04 .16 .12 107 0.1 0.6 0.3
1 min after exercise
.06 .06 .08 .08 .16 83 0.1 0.5 0.3
3 min after exercise
.08 .06 .06 .10 .20 79 0.05 0`.5 0.2
8 min after exercise
.06 .06 .06 .14 .12
Immediately after
coldpress.08 .08 .06 .18 .08 68 0.05 0.4
0.1
1 min after coldpress
.04 .05 .06 .18 .12 71 0.05 0.5 0.1
3 min after cold press
.04 .06 .06 .16 .12 78 0.05 0.4 0.1
8 min after cold press
.06 .08 .04 .16 .10 83 0.05 0.4 0.1
SAMPLE CALCULATIONS:
Rate of paper= 25mm/sDistance between interval= 23mmDuration between interval = 23/25 = 0.92 sHeart rate = 60/0.92 = 65.2 beats per minute
Duration of P wave=3/25 = 0.12sDuration of PR segment = 1.5/25 = 0.06sDuration of QRS wave=2/25 = 0.08s
Duration of ST segment=2.5/25 = 0.10sDuration of T wave=5/25 = 0.20s
10mm = 1mV 1mm = 0.1mVTherefore the amplitude of the P wave is = 2 x 0.1 = 0.2mVThe amplitude of the QRS wave is = 11.5 x 0.1 = 1.15mVThe amplitude of the T wave is = 3 x 0.1 = 0.3mV
DISCUSSION:
The body mass index [BMI] was used on all individuals in this class data set to determine their
general health from their BMI results. This allowed for the separation of individuals into
“normal/healthy”, “underweight”, “overweight” and “obese” categories. Male subjects were
contrasted against female subjects. By utilizing BMI information, the data set was standardized,
thus allowing all data to correlate correctly with each other.
Pulse rate and blood pressure would expectedly be lowest when the individual was in a laying
position as compared to sitting and standing positions. In the seated position, the hydrostatic
influence acts on the carotid sinus of the heart. The blood pressure and heart rate would also
be higher upon standing as the heart has to work against the force of gravity to pump blood up
towards the head as well as everywhere else in the body.
In all male subjects, in the laying position the heart rate and blood pressure were lowest. ON
sitting up the heart rate increased slightly, and on standing the heart rate was highest.
However the readings on blood pressure for all on standing were fluctuated from those of the
seated position. This is most likely due to anomalous readings from those taking
measurements. Some blood pressures rose while others dropped. The blood pressure readings
should drop when moved from seated to standing position as standing upright can lead to 500
– 700 mL of blood pooling into the legs due to the forces of gravity. The systolic pressure of the
males ranges from 84 – 140 mmHg. The differences in the values between each category were
prevalent. The lowest blood pressures were seen from the males in the “normal” category.
These males were deemed healthier than the others according to the BMI and as such, should
have stronger heart able to pump blood more efficiently. The highest heart rates were seen in
the overweight males.
The females showed the lower heart rate to belong to the overweight category. The healthy
females had heart rates which showed no discernible trend whilst the underweight female had
a heart rate which fell within the range of the healthy females. Having only one overweight and
underweight subject introduced a great deal of difficulty in discerning any trends from the data.
Discerning any trends from the females with regard to blood pressure with relation to body
orientation also proved difficult as values were scattered.
Exercise raised the heart rate and blood pressure of all individuals who were tested; however,
the responses following the bout of exercise were very different. The heart rate of healthy
males increased rapidly during exercise, a heart rate (105 beats per minute), and then quickly
returned to close to normal after 5 minutes. A similar situation occurred with respect to the
blood pressure of the healthy males. Their blood pressure increased only slightly and quickly
returned to normal after 5 minutes. The underweight males’ heart rate increased more slowly.
Their blood pressure also increased slightly and did not return to normal after 5 minutes. The
obese male had a heart rate which increased rapidly, higher than that of the other males before
returning to normal rate at a much slower rate. The blood pressure of the obese individual also
fluctuated and varied more than both the healthy and underweight males. This is most likely
due to the heart attempting to satiate the demands of the body.
The healthy females had a similar reaction to the healthy males. Their heart rate spiked quickly
during exercise (from 80.7 BPM to 114 BPM) and then returned to close to normal at a
moderate pace after 5 minutes. The blood pressure of the healthy females increased slightly,
and gradually decreased as time passed. The underweight and overweight category in females
showed a rapid spike with exercise before returning to close to normal much faster than that of
the healthy females. This most like is due to there being only one female for the overweight
and underweight classes respectively giving rise to biased data.
Individuals classed as healthy have faster recovery rates due to the autonomous nervous
system being trained to have such a response. It is assumed that healthier or healthy individuals
exercise more often than those who are overweight or underweight. The parasympathetic
nervous system allows for the slowing of the heart rate and lowering of blood pressure after
exercise. It becomes more efficient due to the outcome of exercise.
When underwater, one must hold one’s breath. The body enters a state known as the
mammalian diving reflex. Submergence in this case was stimulated by the subject simply
holding their breath for as long as possible. From the results for males, no discernible trends
were observed with heart rate or blood pressure. Some individuals had values which remained
constant, and others fluctuated with no discernible reason. The same fluctuations were seen in
females and thus made observing trends difficult. The mammalian diving reflex stimulates
peripheral constriction of the blood vessels in the outer extremities of the body. This avoids the
circulation of blood to non-vital parts of the body while maximizing the supply of oxygen to vital
organs, such as the brain (Cheng, 2010). This causes the lowering of heart rate and blood
pressure when holding breath which should have been observed in the data set.
The cold pressor test triggers a vascular sympathetic activation and an increase in blood
pressure in healthy persons. However the heart rate has high variability from person to person
(Mourot, 2007). After the healthy males removed their hands from the ice water, there was a
slight increase in blood pressure, and then a steady decrease as time progressed. Heart rate for
the individuals fluctuated too greatly to discern any trends. The ECG of the male corresponded
with these results. The underweight males had a very fluctuating heart rate.
Healthy females had a steady decrease in heart rate and blood pressure, which started to
increase back to normal from the minute after. The underweight female had a fluctuating heart
rate. Her blood pressure increased a bit and then decreased gradually. The cardiac cycle was
most affected by the cold pressor test, as it caused the most variance in the ECG.
Key sources of error could have been introduced every time blood pressure was taken. This is
subjective as to which point the blood was heard through the stethoscope i.e. the Korotkoff
sounds. Error may have also been introduced through pulse readings. Also with regards to
exercise, the exercise done by each individual was not standardized and as such some
individuals may have exerted themselves to a greater extent than others. This experiment may
be improved by using a digital sphygmomanometer to take readings of blood pressure and
pulse rate. Also a larger sample size with equal amounts of individuals in the various BMI
classes would allow for less discrepancy in data collection and give rise to more accurate
results. Also standardization of the exercises by controlling the amount and the intensity should
be implemented to give greater validity to the results.