The results indicate that caffeine did in fact have an affect on the heart rate and so did increase the number of heart beats per minute. However, there were no significant changed that occurred in the heart rate when more caffeine was used. Since caffeine takes approximately 15 minutes to have an affect, I believe that the caffeine had not be digested or kicked in yet so I think if the results were taken at a later time the change in heart rate would be greater. Hence, this investigation could be improved by recording the heart rate at 15 minute intervals for at least 30 minutes for better results. In addition, another improvement that could be made would be to use more people. Not only that, but to closely monitor individual’s diet and behaviour
