If you have not been able to meet your gym goals despite persistent efforts to wake up early or hitting that running session on a hot summer afternoon, blame it on your personality.

Conscientiousness has long been tied with healthy behaviours.

Narrowing their focus to "planfulness" -- lead researcher Rita M. Ludwig and colleagues Sanjay Srivastava and Elliot T. Berkman, they zeroed in on psychological processes -- such as mental flexibility, and a person's ability to make short-term sacrifices in pursuit of future success that contribute directly to achieving long-term goals.

"What's new in this study is that we used an objective measure of goal progress that could be recorded as participants naturally went about their lives: their check-ins at a local gym".

The findings, published in the journal Psychological Science, suggest that self-reported levels of the trait called 'planfulness' may translate into real world differences in behaviour.

The team analyzed gym attendance of 282 participants over a 20-week period.

The participants, many of whom were students, provided a written description of their exercise plans and completed measures of self-control and grit.

While all participants experienced a similar decline in gym attendance over the course of each semester, individuals who rated themselves high on "planfulness" items such as "developing a clear plan when I have a goal is important to me" went to the gym more throughout both semesters compared to those who ranked themselves lower on "planfulness".

While there was a small, but significant relationship between participant planfulness and the level of detail in their physical activity plans, descriptiveness was unexpectedly found to have no relationship with gym attendance, Ludwig and colleagues noted.

"It seems logical that people who are successful with their goals would be able to write in detail about their planning process," said Ludwig.