Coursework Investigation: Plan experiments to determine the effects of exercise on the pulse rate/heartbeat

GCSE Physical Education (Sport & Coaching)

Plan experiments to determine the effects of exercise on the pulse rate/heartbeat

PLANNING

I plan to carry out an experiment where I will test the affects of exercise on the pulse. To make sure that all the results are clear, I will ensure my experiments are simple yet effective. In order to get a general idea of the answer to the question, I am going to start by:

Testing someone with an average body frame and body-fitness.
Carrying out two experiments;

Measure the heart beat before, during and after one minute of slow jogging on the spot.
Measure the heart beat before, during and after one minute of fast jogging on the spot.

This will give me an idea as to how exercise affects the pulse rate as well as seeing if results change by different degrees of difficulty. I will keep all factors in the experiment the same apart from the varying types of exercise in each experiment.

There will be minimal equipment needed to carry out the experiment:

A stopwatch
A stethoscope
A suitable table to record results in.

Using my own scientific knowledge on the subject, I have made a couple of predictions.

When the person starts the exercise, their pulse will not dramatically increase (initially), because this is anaerobic exercise, which is a type of exercise, which does not use up oxygen to fuel the exercise. Instead, the body uses the body’s store of carbohydrate (glycogen). The heart rate will, nevertheless, increase to fuel the body’s increased requirement for oxygen.

However, it could be that after 45 seconds of the fast jogging, this would turn into aerobic exercise. This means their heart will beat faster and in turn the person will breathe more quickly and deeply to get more oxygen into their system. The oxygen is carried away from their lungs by their blood. The slow jogging, on the other hand, would remain anaerobic exercise because the exercise period is short – just one minute long.

Another prediction I make is that after the exercise has been carried out, the heart rate will not drop dramatically at the start. Instead, it will take time to recover as the body returns to its original state. Fast jogging will increase the heart rate more than slow jogging, because it is a more vigorous and energetic type of exercise.

This is a preview of the whole essay

I predict on the more vigorous jogging exercises, that the subject’s heart rate would be higher. The heart has to pump blood around the body quicker. There are a few reasons for this. Before exercise, the sympathetic nervous system allows adrenaline into the bloodstream. Furthermore, the metabolic rate increases. The increased metabolic rate causes carbon dioxide to build up in muscle tissue. Adjustments are made in ventilation because you need more oxygen to replace the carbon dioxide. The heart rate increases to carry the waste away and replace it with oxygen quicker.

I will take 6-7 readings at various points in the exercise;

The resting pulse
The pulse after 30 seconds of exercise
The pulse after 60 seconds of exercise
The pulse after the exercise is finished – reading at 10 seconds after
The pulse after the exercise is finished – reading at 20 seconds after
The pulse after the exercise is finished – reading at 30 seconds after
The pulse after the exercise is finished – reading at 40 seconds after

I will carry out a preliminary experiment to make sure the experiment provides good results, works well, is safe, and also is easy enough to carry out. This ensures that the actual experiment will work as I have predicted. The results from the preliminary proved to be as I expected, with the pulse rate slowly increasing with slow jogging, and the pulse rate increasing relatively faster with fast jogging.

OBTAINING EVIDENCE

I will test only one person to keep the experiment simple, but I will do varying types of exercise. In this way, I can see how the different types of exercise affect the pulse rate and record the results accordingly.

I will describe the exercise and pulse rate by giving a detailed description of each one. I will measure pulse rate in ‘BPM’

I will repeat parts of the experiment which seem irregular to see if the results vary hugely from the original result. If so, there must have been an error in my original experiment, so I will take it again. However, if on the second time round there is a relatively small difference, I will leave the result because irregularities will occur in most experiments.

I will present my results in a clearly laid out table where comparisons will be easy to make. On the next page are my results.

Below are the results for the effects of exercise during slow jogging on the spot.

Slow jogging on the spot

Here are the results displayed in a bar chart.

Here are the results displayed in a line graph.

Below are the results for the effects of exercise during fast jogging on the spot.

Fast jogging on the spot

Here are the results displayed in a bar chart.

Here are the results in a line graph.

ANALYSING EVIDENCE

I believe both graphs are useful in terms of comparing, but I found the line graph to be more useful. This was mainly because you could see where the pulse peaked and then how fast it dropped down again. The line graph also showed every second of the experiment so you can see what the heart rate is at 45 seconds into the experiment as well as 30 and 60 seconds in. Whereas on the bar charts they only show you what the BPM is for a second. I could compare both this result and the other result.

The pattern on both the slow and fast jogging graph follows as this: From the resting pulse, the heartbeat increases relatively quickly and peaks at the end of the exercise (60 seconds). Then as the exercise ceases, the pulse does not immediately drop, but slowly progresses back down to its normal resting rate.

It would be necessary to use a line of best fit on a line graph to get a more flowing, approximate result, apposed to erratic lines. If there are any irregularities, I will identify them.

As identified in the planning, my knowledge proved to be correct.

‘When the subject starts the exercise, their pulse will not dramatically increase because this is anaerobic exercise’ – This shows in the line graphs. The subject’s heart rate increased minimally after 25 seconds of exercise: just a 10bpm increase for fast jogging and 8bpm for slow jogging.

My predictions were backed up well; I discovered that the heart rate did increase, mostly due to the factors of:

The sympathetic nervous system allows adrenaline into the bloodstream.
The metabolic rate increases.
Carbon dioxide builds up in muscle tissue causing adjustments in heart rate to carry the waste away and replace it with oxygen quicker.

EVALUATION

I thought my experiment worked successfully. It worked well in conjunction with my preliminary experiment and the outcome was as I expected. The experiment was simple to keep results clear and easy to analyse. However, to improve my investigation I could have tested more people and compare the different fitness levels. Overall, I was pleased with my results and felt they were accurate.

In this experiment, there were no anomalies on results graph. This indicates that there were no irregularities, inconsistencies, or errors in my experiment.

I ensured the conditions for each experiment were the same. However, a few factors were out of my control. When I did my preliminary test and when I did it the real time round, the subjects fitness could have changed over this period. Furthermore, I could have used a heart-rate monitor to measure a heartbeat more accurately.

After my investigations, I have come to the conclusion exercise makes your heart beat faster.