The Effect of Exercise on 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:
- Exercise
- 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
Investigating the effect of exercise on the heart rate of humans
Apparatus
- Heart rate monitor
- Stationary exercise bike (at a set resistance level)
- One group of healthy humans
Method
- 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 exercise
- Ask each individual to cycle at a vigorous pace on the stationary exercise bike for a set period of time
- It may be that the individuals are asked to maintain a particular RPM (revolutions per minute) while on the bike for 5 minutes
- After the five minutes of exercise is over, use the heart rate monitor to record the heart rates of each individual
- 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 after exercise
- Present the results in a graph or table form
Limitations
- Care needs to be taken when selecting the exercise intensity
- If the intensity is too low, it may not have an effect on the heart rate
- If the intensity is too high, it could but the safety of individuals at risk
- 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 care would need to be taken to find individuals with a similar life history (same sex, age, weight and height etc.)
Examiner Tip
Exams may ask about the safety and ethical considerations when studying the heart rates of humans. An experiment should be designed so that the safety of any of the subjects is never at risk, for example they should not be pushed to exercise at such an intensity that could cause a heart attack.