Heavy On My Mind

Title of Study: An investigation into the relationship between fitness level cognitive function and dietary fat


Principal investigator: Jennifer Fortune

Obesity, or being overweight, isn’t problematic only because of the extra pounds. It also increases a person’s risk of cancer, diabetes and heart disease. But what does it do to your brain?

Recent research indicates that obesity may also lead to problems with memory, thinking and reasoning. The good news is that the damage may be undone through weight loss and exercise.

The aim of this aspect of the study is to measure dietary fat intake, resting Respiratory Exchange Ratio (RER) and cardiorespiratory fitness of participating subjects of all ages, with a view to assessing whether cognitive task performance is correlated with dietary fat intake and physical fitness level.


You will be asked to enter your unique ID number. You will then fill out two quick questionnaires.  One is called the Physical Activity Readiness Questionnaire (PAR-Q) which will assess your suitability to complete the exercise test. The other will assess your dietary fat intake.

You will be asked to complete three computerised cognitive tasks that assess different kinds of memory. These tasks will be carried out on a computer and will take no longer than ten minutes to complete.

You will then have your Resting Respiratory Exchange Ratio (RER) measured. This is the ratio of carbon dioxide production to oxygen consumption. Measuring this ratio can give an indication of which fuel (carbohydrate or fat) is being used to supply the body with energy. An RER of 0.70 indicates that fat is the predominant fuel source, 0.85 suggests a mix of fat and carbohydrates, and a value of 1.00 or above is indicative of carbohydrate being the predominant fuel source. This measurement will take 3 minutes.

During the measurement you will wear a soft rubbery facemask. The facemask is connected to a small device that analyzes the volume and concentration of oxygen and carbon dioxide in the air you breathe out. This device is worn in a harness which is put on over your chest or back.

You will then be invited to participate in a submaximal, treadmill-based fitness evaluation. You will have your resting heart rate (HR) and blood pressure (BP) measured.  You will then be asked to walk on the treadmill for 1 minute at 1.7 miles per hour at 0% incline to warm up. You will then be instructed to walk for 3 minutes at a speed of 1.7mph at a 5% incline, followed by 3 minutes walking at 4mph and 5% incline. Finally, you will engage in a warm down for 3 minutes at 1.7 mph and 0% incline.

Your heart rate will be used to calculate your maximal oxygen uptake while exercising which will give us an indication of your aerobic fitness level. In addition we will measure energy expenditure, the amount of energy, measured in calories that you use.

Members of the public attending the science gallery will be able to view the experiment in progress from a distance.

There is no obligation to participate and you may withdraw from this study at any time. If you feel unwell at any stage during the exercise protocol you should say so immediately and the treadmill will be stopped.


Volunteers will obtain a measure of the following:

Fitness level.

Respiratory exchange ratio.

Energy expenditure


The risks associated with an exercise treadmill test are about the same as those that may happen during a session at the gym.  Risks include fatigue, muscle soreness, shortness of breath, cramping and abnormal blood pressure. To minimize these risks you will have a trained professional performing this procedure. In addition, you will have your blood pressure and heart rate monitored throughout the test.

The exercise protocol we have chosen, consists of a 2-stage walking protocol. Similar fitness tests are regularly used in clinical settings to assess the fitness of diseased or elderly patients and constitute light to moderate exercise.

Exclusion from participation

You cannot participate in this study if any of the following are true.

  • You are under 18.
  • You ticked yes to any of the questions on the Physical Activity Readiness Questionnaire (PAR-Q).


Your identity will remain confidential. Your name will not be published and will not be disclose to anyone outside the study group.


This study is covered by standard institutional indemnity insurance. Nothing in this document restricts or curtails your rights.

Voluntary Participation

If you decide to volunteer to participate in this study, you may withdraw at any time. If you decide not to participate, or if you withdraw, you will not be penalised and will not give up any benefits that you had before entering the study.

Stopping the study

You understand that the investigators may withdraw your participation in the study at any time without your consent.


This trial has Research Ethics Committee approval from Trinity College Dublin.

Further information

You can get more information or answers to your questions about the study, your participation in the study, and your rights, from Jennifer Fortune who can be telephoned at 01 896 3613. If the study team learns of important new information that might affect your desire to remain in the study, you will be informed at once.

Heavy On My Mind

Is your fat intake weighing your brain down? How is your food fuel choice affecting your respiration rate and your body’s energy supply? Test out how fit you are and find out how many calories you’re really burning. Get a taste of a memory task to assess if there is any link between your BMI, fitness level and cognitive function.

  • Testing Time: 30 minutes
  • Complimentary Test: Activity Addict?
  • BMI measurement required to order this test
  • Participant Information