cinnamon sticks

Hearty Smells

Science experiment for students who are blind or visually impaired to study how smell affects heart rate and stress.

This science project was done by Donna, who is a student at Texas School for the Blind and Visually Impaired (TSBVI).


Does smell affect heart rate and cause stress?

Note: why does heart rate speed up when we are stressed?



Odor facts:  Younger people are more sensitive to odors than older folks. Women are more sensitive to odors than men. Non-smokers are more sensitive to smell than smokers. People with an empty stomach are more sensitive to odors than people who just ate. People are more sensitive to odors in the morning than in the evening.

Odors can affect behavior;  Mood, level of alertness, levels of anxiety, level of stress.

Unpleasant or Negative odors can have a negative health impact;  nausea, headaches, depression, increased anxiety, Elevated blood pressure, decrease in physical energy, compromise immune system, physical discomfort, increase in anger and stress, and muscular, control problems fatigue and confusion.


If someone smells a pleasant smell I believe that their heart rate would heart rate and blood pressure would calm or slow down. If someone were to smell an unpleasant smell I believe that their heart rate and blood pressure would increase.

As I researched this topic, it became more complicated because not all people consider the same smells pleasant or unpleasant.  For instance, one of my volunteers found tea tree oil to be a pleasant smell, even though I had chosen it as an example of an unpleasant smell.


Step 1. Ask student if they are allergic to anything. Blind fold the person alone in a room allow 2 minutes for  student to calm down before taking measurements.

Step 2. Take heart rate before procedure begins.

Step 3. Have person smell lavender 5 seconds then lemon, next vinegar, after coconut oil, then tea tree oil, and finally cinnamon.

Step 4. Between each scent record heart rate 7 seconds after smelling the scents. wait 5 minutes between each scent.

Taking a student's pulse
Taking a student’s pulse


Average  change of heart rate in beats per minute

Cinnamon – Decrease of 5.8 BPM

Lavender –  Decrease of 1.1 BPM

Lemon – Increase of 2.5 BPM

Coconut Oil – Increase of 3.9 BPM

Tea Tree Oil – Increase of 5.2 BPM

Vinegar – Increase of 6  BPM

Graph produced by the student of her results
Graph of the results produced by the student

Comments from Students:

About Vinegar:

About Tea tree oil:

About Lemon:

About Coconut oil:

About cinnamon:

About lavender:


My results were inconclusive as I discovered that smells are very personal.  What is a pleasant smell for one person may be an unpleasant smell for another.


Other scents were considered including sulfur which smells like rotten eggs.

NGSS Standards:

By Laura Hospitál

Collage of hearty smells

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