What did you find?
Was it the same as you predicted?
Have a think about how you could record your results.
These are just a few ideas - how you present your investigation is up to you. I look forward to seeing the results!
Taking it a bit further: (Additional)
Can you answer these questions:
How could you link what you have found to your knowledge of the circulatory system?
Why is it important to exercise?
What are we doing to our hearts when we exercise? Why is this important?