It takes about six months, on average, to form the gym habit, according to a new study by researchers at Caltech.
According to the same study, published in PNAS, it typically takes a few weeks for healthcare workers to form the habit of regularly washing their hands.
This is the first investigation into habit formation to employ machine learning techniques. Researchers used machine learning to examine data from tens of thousands of people using RFID badge readers at gyms and hospital handwashing stations.
The gym research was conducted in collaboration with 24 Hour Fitness, and the hand-washing study was conducted in collaboration with a company that employs radio frequency identification (RFID) technology to track hand-washing rates in healthcare facilities.
Over the course of four years, the data sets followed more than 30,000 gym-goers, and over the course of nearly 100 shifts, more than 3,000 hospital workers.
Time of day, for example, was found to have no bearing on the development of a regular gym routine. The individual’s past actions, among other things, did play a role. For example, the length of time since a person’s last gym visit was a significant predictor of whether or not they would go again for 76% of gym-goers.
Those who had not been to the gym in a while were less likely to make it a regular habit. Sixty-nine percent of gym-goers tended to frequent the facility on the same days each week, with Monday and Tuesday drawing the largest crowds.
“Contrary to the popular belief in a “magic number” of days to develop a habit, we find that it typically takes months to form the habit of going to the gym but weeks to develop the habit of handwashing in the hospital,” the authors concluded.
“Furthermore, we find that gymgoers who are more predictable are less responsive to an intervention designed to promote more gym attendance, consistent with past experiments showing that habit formation generates insensitivity to reward devaluation.”