# Pulse Rate-Lab Report

BIOLOGY INVESTIGATION

Research Question: What is the effect of physical exercise on Pulse Rate of the human heart?

Hypothesis: As the level of physical exercise increases, the pulse rate will also increase. Females will have a higher pulse rate difference compared to that of males, of the same age group.

Variables:

Independent Variable: Climbing Stairs, Using the treadmill
Dependent Variable: Heart Beat Rate
Control Variables:
The following factors were controlled, or kept the same in this test:
-Room temperature: In the gym: 22
0C ±0.5, On stairs: 250C ±0.5; measured using Thermometer
-Time over which subject was under experiment: 2 minutes ±0.5
-Time of the day: Period 3, 10.45-11.45am
-Time over which subject was allowed to rest before pulse was measured: 20 seconds ±0.05, this was measured using a stopwatch
-Same equipment used to measure pulse rate in order to have standardized results, that is, pulse rate monitor and stop watch, to the accuracy of ±00.5
-Same method used to measure pulse rate
-Time over which pulse rate was measured, after exercising: 1 minute ±0.05
-Speed on treadmill: Level 6, was kept constant throughout
-Same person for tests
-Time for person to rest between trials: 2 minutes ±0.05

Materials Needed:

-Thermometer
-Stopwatch
-Pulse Rate monitor
-Recording Sheet
-Stairs

Procedure for Controlling Variables:

-The time for which subject was allowed to rest before pulse was measured: constantly 20 seconds ±00.5, this was measured using a stopwatch
- A thermometer was used to ensure the accuracy of the room temperature: the gym: 22
0C ±0.5, On stairs: 250C ±0.5
- Time over which subject was under experiment: 2 minutes ±0.5, measured using stopwatch
-Time of the day: Period 3, 10.45-11.45am
-Same equipment used to measure pulse rate in order to have standardized results, that is, pulse rate monitor and stop watch, to the accuracy of ±00.5
-Same method used to measure pulse rate
-Time over which pulse rate was measured, after exercising: 1 minute ±0.05, using stopwatch
-Speed on treadmill: Level 6, was kept constant throughout
-We used the same subject for both sets of exercise so as to make sure individual differences like stamina/fitness level, gender, weight, different diets were kept constant throughout

Procedure of Data Collection:

1. To start with, initial pulse rate was measured so that the rise/fall can be seen clearly. This was done for 1 minutes ±0.05 using a stopwatch
2. The exercising was then carried out: In each trial, the subject was supposed to climb down and up flights of stairs for a total of 2 minutes ±0.05
3. After exercise, the patient was to stand still for 20 seconds ±0.05, after which the pulse rate was measured
4. This was then recorded –accuracy was attempted to be maintained
5. Pulse rate was then allowed to reach initial rates so as ...

#### Here's what a teacher thought of this essay

While this investigation into the effect of exercise on heart rate had a number of positive aspects to it, it also suffered from some very basic weaknesses that undermine the validity of the data collected. It is worth studying these areas since they are fairly common among students who are coming to experimental science for the first time. [1] Science investigations are about testing a hypothesis. A hypothesis is an idea resulting from observations, together with researched scientific knowledge from previous work. In this case, the hypothesis was not supported by observation or knowledge. [2] The independent variable must have a range of values in order for a trend to be observed. Here, the writer tests only two I.V. values. [3] In order for data to be considered valid (useful), it must be reliable, and reliability comes from large sample sizes, ie. repeating readings . In this case, the writer has only one male and one female subject. [4] The results are discussed using too much 'hearsay' and not enough human physiology knowledge. The physiology of circulation is well documented and any pulse rate investigation should draw on the vast reservoir of knowledge online. The structure of the report is adequate, although it lacked a risk assessment, but the key weaknesses above would prevent this gaining high grades at GCSE