"This method makes heart rate research more inexpensive, portable and straightforward," said James Heathers, the doctoral student from University's School of Psychology behind the project.
"The sensor, placed on a finger instead of using electrodes on the chest, is so small we can mail it to study participants," added Heathers, according to a Sydney statement.
Data on tiny fluctuations in our heart rate provides critical information on the state of our nervous system, and is essential for a range of psychological research including on anger, anxiety, stress and self-control.
At the moment, heart rate variability (HRV) research is done in a university lab with a group of study participants. Electrodes are attached to their chests to measure HRV and the data is recorded, one person at a time, using a lab computer.
"The idea struck me because I'm by nature impatient and my area is psychophysiology -- which is all about the relationship between physiological and psychological states," said Heather.
"By providing people with a sensor and then using their smartphone to process the data, we are no longer tied down to booking appointments in a university laboratory, and can record dozens of separate data streams at the same time."
Heathers collaborated with Simon Wegerif, a biomedical engineer. Wegerif's company, HRV Fit Ltd, already had an HRV phone app -- iThlete -- widely used by professional sports teams and athletes, for whom heart rate variability is an important measurement of their performance and recovery.
The challenge was to adapt a similar app into a tool that can collect and provide HRV data in a way useful to researchers.
"We have run tests of our sensor linked to a smartphone and the software is working very well. I expect it to be up and running -- and available for free -- in the next few months," said Heathers.
Heathers plans to use the HRV data to expand theories on the day-to-day fluctuations of the nervous system, and to collect data from groups that are traditionally hard to access.
These results were presented at the Australasian Society for Psychophysiology conference 2012.
