Exercise and Heart

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Aim: Finding out how exercise affects the heart rate and breathing rate. Hypothesis: Exercise exists in different forms and has many benefits; it improves the oxygen-carrying capacity of the blood, development of bones, strengthens muscles and the lungs capacity plus it can make you feel good. There are different exercises and intensities for different benefits. Lower intensity exercises are not designed to work the body as hard. As a result less oxygen is needed and less waste is in excess. However even low intensity exercises require more substances to be carried out than if your body was in its resting state. Therefore different concentrations of substances are required for different intensities of exercise. In effect this affects your heart and breathing rate. (Jones & Jones, 1984) (Ross, 1978)

Null Hypothesis: Exercise has no effect on the heart rate or breathing rate.

The overall rate of the heart and breathing increases during exercise. The heart beats faster, allowing blood to supply substances required by the cells to respire. Oxygen is needed to replace the oxygen used up in respiring cells, while at the same time the cells produce carbon dioxide that needs to be removed from the body. The heart rate increases to pump blood around the body quicker, ensuring oxygen is constantly dissociating from the blood to the cells. At the same time the breathing rate increases to increase the rate of gaseous exchange of oxygen and carbon dioxide, and remove excess waste from the body as soon as possible. (Jones & Jones, 1984) (Ross, 1978)

“Exercise, although essential both for early, sudden muscle contraction ( a few minutes ) and for prolonged, sustained exercise, muscle food stores are not enough. The contracting muscle must also take up glucose from the blood.” (Ross, 1978, p. 705)

“Aerobic exercises improve lung capacity. Exercising muscles need extra oxygen, which is supplied to them by breathing faster and more deeply. If you regularly do exercise which make your muscles demand extra oxygen, called aerobic exercise, this helps your respiratory system to become efficient at getting oxygen into your blood.” (Jones and Jones, 1984, p. 279).

Risk assessment:

Chemical/Procedure| Hazard| Precaution|

* Stepping off and on exercise step| * Slipping off step| * Dry shoes * Appropriate support| * Exercising| * Pulling muscles * Feinting/Blackout * Spraining ankles| * Appropriate stretching before exercise * Supervised by professional * Don’t force ankles onto the surfaces * Try to be light on the feet| * Wide breadths of movement| * Inflicting contact on others| * Suitable space for procedure| Variables:

Constant Variables
* Exercise step
* Number of steps taken
* Resting period
* People recording pulse and breathing rate
* Temperature of room

Independent Variables
* Exercise

Dependent Variables
* Heart rate
* Breathing rate

1. Record the pulse (preferably from the wrist) for 30 seconds of the person participating before exercise. 2. Double the number of pulses – this gives an estimate of the heart beats per minute 3. Place hand on the lower back of the person participating before the exercise and count the number of times the person inhales and exhales in 30 seconds then double it – this is the breathing rate per minute. 4. These are the heart rate and breathing rate at rest.

5. Explain to the participant the concepts of both exercises: a. Slow 20: Slowly climb onto and off the step for doing 20 steps in total. b. Fast 20: Climb onto and off the step as fast as possible for 20 steps in total. 6. After the participant has done the “Slow 20” exercise, record the heart rate and breathing rate. 7. Stop the stopwatch and reset

8. Next record the heart rate and breathing rate after the participant has undergone “Fast 20” exercise – however keep the stopwatch running for an additional three minutes 9. At the end of the three minutes record the heart rate and breathing rates 10. Work out the averages of all the results

11. Plot results in a suitable table

Results Table
Heart Rate
Rest| Slow 20| Fast 20| 3 minute rest|
76| 107| 130| 72|

Breathing Rate
Rest| Slow 20| Fast 20| 3 minute rest|
18| 23| 33| 20|


As the intensity of exercise increased, so did the rates of the heart and breathing. After a small period of rest, the heart rate and breathing rate both decreased to a point close to their resting rate. This proved the stated hypothesis. First, the hearts average resting rate was recorded to be 76 bpm. The heart is therefore transporting oxygen and removing carbon dioxide at a reasonably steady rate via the blood. During the low intensity exercise (Slow 20) the heart rate increases to 107 bpm, which further increases to 130bpm at a higher intensity level (Fast 20). The heart therefore needs to beat faster to increase the speed at which oxygen is carried to the cells and the rate at which carbon dioxide is taken away by the blood. Oxygen is required by the cells to carry out respiration, this provides the energy in the form of adenosine-triphosphate (ATP) which is a molecule required for muscular contraction.

As exercise takes place, oxygen is used to form ATP, which needs to be replaced. Carbon dioxide is also built up in the same cells due to muscle contraction, and this excess CO₂ needs to be removed. The breathing rate increases to increase the gaseous exchange between oxygen and carbon dioxide. Oxygen is breathed in through the atmosphere and diffuses into the thin walls of the alveoli, which then diffuses into the blood along the capillaries. The blood then passes the respiring cells and the oxygen it contains diffuses into the cells. At the same time, the excess CO₂ diffuses from the respiring cells into the blood, along through to the alveoli and is breathed out. This maintains equilibrium in the body of oxygen and carbon dioxide. “To create energy for physical efforts lasting more than 1 minute, muscles need oxygen. The harder your muscles work, the more energy they need and the more you must suck wind to supply them with oxygen.

Also, the more oxygen your muscles use to create energy, the more waste (carbon dioxide) they produce. Exhaling expels this carbon dioxide from your system.” (Why Does Exercise Increase Heart Rate And Breathing Rate?, 2012) “Blood is the vehicle that delivers oxygen to and removes carbon dioxide waste from the working muscles. To deliver more oxygen and remove more waste products, the heart pumps more blood. According to the American College of Sports Medicine (ACSM), at lower intensities (up to 50% of your maximum cardiac output) your heart can meet the increased oxygen demand by increasing both heart rate and stroke volume (the amount of blood pumped with each beat). However, beyond 50% of cardiac output, increasing your heart rate in proportion with your effort is your body’s only way to deliver more oxygen to the muscles.” (Why Does Exercise Increase Heart Rate And Breathing Rate?, 2012) Graph


The experiment was good enough to gain results as the results were those predicted by the hypothesis. The experiment was carried out by five people at random in terms of height and weight, the individual weights were taken and the average result were used as the final result – results used to be plotted onto the graph. The combination of random sampling and number of repeats increases the experiments reliability as it tries to keep the results obtained as much due to chance as possible. Also, because the results were predicted by the hypothesis it suggests that this data can be used to find out what was being looked for – the effects of exercise on the heart and breathing rates. Validity is therefore increased, adding more support for the experiment to be a suitable method for finding effects of exercise on the heart and breathing rates.

No anomalous results were found, the results followed the predicted trend, the reason for this result could be due to the nature of the body and how it counter reacts with the external influences on the tissues and organs. The secretion and inhibition of certain substances are essential for the body to sustain itself in a stable state during the effects of exercise.


I would improve this experiment by using more accurate equipment to improve the accuracy of the overall experiment. I would run repeats to see if my results complimented each other to increase the reliability. The difference is I would run the experiment in the same way which may differ from other people’s subjective habits. More accurate equipment could have been used to improve the accuracy of the overall experiment.

The heart rate is measured by finding the pulse of the body, a more precise method of determining pulse involves the use of an electrocardiograph, or ECG (also abbreviated EKG). Commercial heart rate monitors are also available, consisting of a chest strap with electrodes. The signal is transmitted to a wrist receiver for display. Heart rate monitors allow accurate measurements to be taken continuously. (Heart Rate, 2012)

The breathing rate can be measured over a full period of 60 seconds to get more accurate results. Repeats using the improvements to accuracy of finding the heart and breathing rates would yield more reliable results.

The exercise itself is very subjective to each person. Their interpretation of slow could be different to other people, which would affect the time it takes each individual person to take twenty steps. The exercise could then be controlled by suggesting a method to keep generalise the types of speed people would undergo during the exercise. For example, people could use counting as a reference point for when they should stand onto or off the exercise step.

* Jones, M. And Jones, G. 1984. Biology: The Press Syndicate * Ross, G. 1978. Human Physiology: Year Book Medical Publishers * Why Does Exercise Increase Heart Rate And Breathing Rate? (2012)Breathing Rate & Heart Rate [Online] Available at: http://www.livestrong.com/article/109267-exercise-increase-heart-rate-breathing-rate/ (Accessed: 15 November 2012) * Heart Rate (2012) Measurement [Online] Available at: http://en.wikipedia.org/wiki/Heart_rate (Accessed: 16 November 2012)