Can caffeinated drinks affect the human heart?

I always wondered why people drank caffeine in the morning so that they could get energized. I wanted to know if it could affect the human heart rate, mood, concentration and memory. I tried 3 different types of drinks, and I tested them on my family.
Aryan Sharma
Grade 5


In the end I will figure out that some different types of caffeinated drinks affect the human heart. I think the pistachio latte will affect my family’s heart rate the most!




So I have Found out there are 5 different types of caffeine.      

  1. Coffea Arabica (used for coffee)
  2. Thea sinensis (used for tea)
  3. Cola acuminata (Found in a nut, used in tea or in soft drinks)
  4. Theobroma cacao (used in cocoa and chocolate)
  5. Paullinia cupana (used in snack bars and energy drinks).

I decided to test them out accordingly, like for Thea sinensis I try green tea. I'm probably gonna go to starbucks to get all the coffee and tea, and some other convenient stores to get my coke. 



Independent Variables:

  • Type of caffeinated drink (Pistachio latte, Matcha green tea, Coke)

Dependent Variable:

  • Heart rate
  • Mood
  • Concentration
  • Memory

Controlled Variables:

  • All drinks have the same amount of fluid (12 fl oz)


I had to lower the number of people to test, because of Covid-19. But I know what types of caffeinated drinks I'm going to test out.

Here are the caffeinated drinks:

  1. Pistachio Latte
  2. Matcha Green Tea
  3. Coca-Cola 

I will try this all out on three subjects.

Pistachio Latte: 12 fl oz, 75 mg of caffeine

Matcha Green Tea: 12 fl oz, 55 mg of caffeine

Coke: 12 fl oz, 34 mg of caffeine

I will record their Age and Gender, because if subject #1 has a different circumstance to coffee and subject #2 doesn't, I can take note of that, and explain why this happens after a bit of research!

Here are my hypothesis for each of the caffeinated drinks:

  1. (Coffee drinks) The subjects are  not going to do very well on the test. They will have a hard time going to sleep. They will need more!!
  2. -Soft Drinks(Coke)-  The subjects might have a small struggle on the test. I really want to know what happens on this drink!
  3. I think Tea is just a little worse than coffee, I think that you would just need more!!!





Matcha Green Tea Tests:

Subject #1

Female, 15

Time of test: Right after dinner ~6:30

Before: I was getting a small headache, but nothing minor-I could handle it, I ate my dinner like 15 minutes ago, I hope my dinner doesn't make a reaction with the green tea! 

After: My first sip, ahhh.. Yum.. After a bit my headache grows, I feel a little tired, I want to go to sleep, But I can't. I way too awake! I need more of that green tea, It was so good! I start to feel very warm, my headache is very bad, and I suddenly had to go to the washroom. 

Number Memory test: 4/7

Bpm: (Before) 84 (After) 79

Word Test: 8/12


Subject #2

Female, 43

Time of test: 5:00pm 

Before: I just finished teachers convention at 4:00, my last class was yoga. I took a nap for an hour, waking up to drink this green tea!

After: I took a sip, and suddenly I felt like my brain lit up! I felt pretty energized, so I ran to the kitchen and did some work. I came a little later, and started to work on my school work. I felt pretty normal, just a little energized! 

Number memory test: 7/7 

Bpm: (Before)  87 (After) 79 

Word test: 11/12 

Subject #3

Male, 43 

Time of test: Right after dinner ~6:30

Before: I came downstairs from my work and ate dinner. My dinner was spaghetti, and that was heavy. I went for my routinely walk, and I came back about 20 minutes after. I wonder what’s going to happen!?

After: I drank the green tea, first sip, yum! I drink the whole cup after 10 minutes, and I go back to my work feeling a bit more energized. The green tea did not affect me that much. I wonder why? 

Number memory test: 6/7 

Bpm:  (Before) 82 (After) 72 

Word test: 10/12 

Pistachio Latte Tests:


Subject #1

Male, 43

Time of test: 9:00am

Before: I feel lazy, and maybe I could go for a power nap, I just don't want to go to bed. I feel pretty normal!

After: This tastes so good, I'm loving it! It is very addicting, I want a lot more. When I come home I feel very awake, I don't feel sleepy at all! I feel like I can finish all my work in an hour! After about 30 minutes, I start to feel fatigue, I need more coffee. I try to go to bed but I can't, I have to force myself to sleep! 

Number memory test:  3/7 

Bpm: (Before) 89 (After) 70

Word test: 5/12 


Subject #2

Female, 43

Time of test: 9:00am

Before: I am happy! I want to see what coffee tastes like. I feel active, ready for anything. I hope this coffee doesn't do anything bad to me!

After: I drink a little bit of the coffee, mmmmmm... tastes sooo good… I love it! After about 25 minutes, I go to bed, it's getting late. But I can't, I feel so active! I go downstairs and do some errands. I come up to bed again, but this time I have to go to the washroom really, really, badly! I took a lot of time, I wondered what happened, finally, I realized that I took my medicine before I went to get this coffee. I wonder if this caused it?

Number Memory test: 2/7

Bpm: (Before) 82 (After) 71

Word test: 4/12

Coke Tests:

Subject #1 

Female, 15

Time of test: ~3:00 pm


I’m lazy, like I just want to sit on the couch and watch tv or youtube all day… I feel pretty normal, and I’m very excited to drink the coke!


Sssiipp, mmmmmmm… YUM! At first, I just like the taste, but like 3 seconds later,  I feel like I can reach the moon! I feel elated, like I just won the lottery… I feel energetic, excited, and I need more!!

Number memory test: 7/7 

Bpm: (Before) 89 (After) 94

Word test: 11/12 

Subject #2

Female, 43

Time of test: ~3:00 pm

Before: I just came to my room after eating a snack (Oranges and carrots), and I went to my teachers convention meeting. I was in the meeting for about and hour. I feel pretty tired.

After: After my first sip, I felt a jolt of energy. But that did not last long, I felt normal again and went back on my rest. The coke did not have much of an effect on me! 

Number memory test: 7/7 

Bpm: (Before) 81 (After) 82 

Word test: 11/12


Subject #3

Male, 43

Time of test: ~3:00 pm

Before: I feel pretty energetic. I just came from my routine walk. I feel awake, and I don’t think of sleeping anytime soon. I just took my vitamins, so I hope this coke won’t interact with it!

After: I drank a little bit, and I felt like I just had put a rainbow in my stomach! I feel very excited and energized. After a little while, I started to have some burps, some bad burps. I felt like my stomach was really full, but it wasn’t. I had to lay down and take a rest. I wonder what happened?

Number memory test: 6/7 

Bpm: (Before) 79 (After) 82

Word test: 12/12 













What have I learned?

  • They are excited before they drink
  • They have to go to the washroom
  • They feel sleepy but they can't go to sleep, they're too awake!
  • After their first sip, they have a jolt of energy. They feel happy and energetic.
  • Adults tend to have no effect to very little effect on low mg caffeinated drinks.
  • They feel like they need more to keep them energized!! 


Out of all the drinks, the Pistachio latte decreased the heart rate the most. Also, the heart rate increased the most with coke! The Matcha green tea was just in the middle, and it generally decreased the heart rate. (The next slide will give a graph about this) 

Speaking of which drink affected the heart rate the most, the number memory and word tests were lowest for the pistachio latte, with an average of 36%(Number memory and word test)! The coke had the the best grades, with an average of 95%(Number memory test) and 94% (Word test). Again matcha green tea is just in the middle, with an average of 81%(Number memory and word test) ! 



My hypothesis was correct! I thought that the pistachio latte would affect the human heart the most, and it did! 

I did not think that a latte could decrease a human heart rate very drastically. I thought that latte’s were okay, and people had no problem drinking it. 

Well.. I was wrong. The caffeine in latte and other caffeinated drinks can affect not just only the human heart rate, but a human’s mood, concentration, and memory. 

I am very grateful for my family to take out of their day and help me in this project. I have gained lots of knowledge and I can use it in my future. I hope you enjoyed this project!




I will be testing how different types of drinks with caffeine affect the heart rate of the human body Note that I will be representing this information on a powerpoint.

For my experiment, I will get about 5 volunteers (my family members, including me) and give them a caffeinated drink, (before this I will get their heart rate) after about 30 minutes, I will get their heart rate, I will also check their mood, concentration, and memory. I will do that by putting them to a variety of tests. I will do this for about 3 different types of caffeinated drinks. I will see which type of caffeinated drink impacted the heart rate the most. 

I will go on a variety of different websites to figure out my information, I will go on videos and check out books, I will make sure the data is correct. I will also give cool facts that will blow the judges minds!

I always wondered why people drank caffeine in the morning so that they could get energized, I wondered if there was something else that was healthier to drink so they could get energized, so I did this experiment to test if caffeine really did help.


Sources Of Error

Sources of Error:

  • Constructed at various times
  • Human condition
  • Not all participants took all three drinks. 



  • What are the different types of caffeine?: The protein works. (2019, October 16). Retrieved February 21, 2021, from
  • Caffeine: How much is too much? (2020, March 06). Retrieved February 21, 2021, from

  • Caffeine: Overview, uses, side effects, precautions, interactions, dosing and reviews. (n.d.). Retrieved February 21, 2021, from

  • Caffeine content of drinks. (n.d.). Retrieved February 21, 2021, from

  • Caffeine the truth about caffeine the worlds most consumed ... (n.d.). Retrieved February 21, 2021, from       (This is a book)


I would like to acknowlege my mom, sister and dad for taking their time out and helping me in this project, I really appreciated it! 

I would also like to thanks my sister for giving me a few ideas along the way of my project, she also edited my project to!