Caffeine is a stimulant found in coffee, tea, soft drinks and other drinks and foods. After consumption, caffeine is absorbed into the blood stream and carried throughout the body and to the brain. In moderate amounts (~300 mg per day) it causes increased attentiveness, it reduces feelings of fatigue, and it enables most people to think clearly and concentrate for longer periods. Caffeine also increases heart rate and rate of respiration. In large quantities (>600 mg per day) its effects are magnified. People sometimes feel irritable, distracted and tense.   People often use caffeine to increase mental alertness. Some people are more sensitive than others to the effects of caffeine. People who consume caffeine regularly may build up a tolerance to its effects. Further, since caffeine is mildly addictive, people who regularly consume caffeine may experience some withdrawal effects if they stop consumption.   The Study In this study, three people each consumed varying levels of caffeine and recorded how they were feeling on a daily basis. Caffeine was administered at 8 am on day 1, day 2, day 3. Subjects didn’t know how much caffeine (or if any) they were consuming each day.   Day 1 – Caffeine dose: 100 mg Day 2 – Caffeine dose: 300 mg Day 3 – Caffeine dose 600 mg Subjects were asked not to consume any caffeine outside the administered dose for the three days of the study.   1. Caffeine affects several of the body’s systems. After examining the data, explain how the body systems are affected and how this relates to mechanisms of homeostasis. Researching Caffeine may aid you in your explanation.     2. Give reasons why the caffeine affected each person differently. Explain your response.     3. Give a possible explanation for Person A’s symptoms on day 1.

Caffeine is a stimulant found in coffee, tea, soft drinks and other drinks and foods. After consumption, caffeine is absorbed into the blood stream and carried throughout the body and to the brain. In moderate amounts (~300 mg per day) it causes increased attentiveness, it reduces feelings of fatigue, and it enables most people to think clearly and concentrate for longer periods. Caffeine also increases heart rate and rate of respiration. In large quantities (>600 mg per day) its effects are magnified. People sometimes feel irritable, distracted and tense.   People often use caffeine to increase mental alertness. Some people are more sensitive than others to the effects of caffeine. People who consume caffeine regularly may build up a tolerance to its effects. Further, since caffeine is mildly addictive, people who regularly consume caffeine may experience some withdrawal effects if they stop consumption.   The Study In this study, three people each consumed varying levels of caffeine and recorded how they were feeling on a daily basis. Caffeine was administered at 8 am on day 1, day 2, day 3. Subjects didn’t know how much caffeine (or if any) they were consuming each day.   Day 1 – Caffeine dose: 100 mg Day 2 – Caffeine dose: 300 mg Day 3 – Caffeine dose 600 mg Subjects were asked not to consume any caffeine outside the administered dose for the three days of the study.   1. Caffeine affects several of the body’s systems. After examining the data, explain how the body systems are affected and how this relates to mechanisms of homeostasis. Researching Caffeine may aid you in your explanation.     2. Give reasons why the caffeine affected each person differently. Explain your response.     3. Give a possible explanation for Person A’s symptoms on day 1.     4. How could you improve this experiment in order to collect better data?     5. What are the ethical concerns with an experiment such as this and how could these be addressed?     6. What are the limitations of this experiment (eg. sample size)? How could these be addressed?   7. How does this experiment impact your decision making?   8. Pose at least one question you still have about the effects of caffeine on the human body.