5.5.13 Investigating Factors Affecting Heart Rate Flashcards
What are some factors which can impact heart rate?
There are a wide range of factors that influence the heart rate of an organism
Experiments can be designed to investigate the effect of a named variable on an organism’s heart rate
These experiments are commonly done using humans
Serious care needs to be taken during these experiments to ensure that no test subjects are harmed
Some of the factors that can influence heart rate include:
Drugs
Caffeine
Alcohol
Sex
Weight
Height
Temperature
Diet
Dehydration
When designing experiments investigating a single factor, it is essential to try and control the other variables
How can you investigate the effect of caffeine on the heart rate of humans?
Use the heart rate monitor to record the heart rates of each individual while at rest
These results can be used to calculate the mean heart rate of the group as well as the range of resting heart rates for the group prior to caffeine consumption
Use the measuring cylinder to pour 200ml of the caffeine solution into a cup (one for each individual)
Ask each individual to consume the drink
Wait 15 minutes
Use the heart rate monitor to record the heart rates of each individual while at rest
These results can be used to calculate the mean heart rate of the group as well as the range of resting heart rates for the group after caffeine consumption
It is important that the individuals taking part are not moving and all sat down so that these variables are controlled
Repeat the heart rate measurements every 15 minutes for 2 hours
This will show the duration for which caffeine has an effect on the heart rate
Present the results in a graph or table form
What are the limitations of this method?
Care needs to be taken when selecting the caffeine concentration
Too much caffeine can be dangerous, while too little may show no effect
It is very difficult to ensure that individuals within a sample group are sufficiently similar
By using the same group for the before and after measurements this is not as much of an issue
If multiple groups were used, with some consuming caffeine and some not, then this would be a major issue and care would need to be taken to find individuals with a similar life history (same sex, age, weight and height etc.)
