People who think positively have a better chance of recovering from serious illness than those who don't, research suggests.
A University of Sydney study indicates optimistic thinking has the power to speed up the recovery of sick people, including cancer patients.
"People who are more optimistic about their recovery when they are ill are more likely to recover," Professor Donnel Briley said.
While patients' health outcomes weren't tracked, Prof Briley said the research focused on finding attributes in people which had been linked to faster recovery in other studies.
Positive people had more of these attributes, he told AAP.
"People who were optimistic were actually stronger," he said.
"For example, we included in one study a hand grip task and we found that people squeezed it longer and more vigorously the more optimistic they were about their futures."
Prof Briley said people who were able to envisage a positive future would most likely have better outcomes.
"Mentally simulating your future is incredibly important to optimism," he said.
"For example, if I'm ill, I might want to exercise more and by imagining myself exercising more it actually makes it more likely that I will exercise more in the future."
The study, which included research from Stanford University and the University of Houston, found a person's cultural background would determine how they were able to optimistically perceive their future.
Prof Briley said people from an Asian background were more optimistic if they thought about responding to specific situations which they may encounter in the future.
People with an Anglo background found it easier to think positively when envisaging a more broad, abstract future, rather than specific situations, he said.
"We asked people to think about their futures and think about what they were going to do to get better and what made the difference was being able to clearly envision themselves implementing these ideas they had in their mind," Prof Briley said.
"The more clear this was the more optimistic they became about their futures."
Positive thinking was not just linked to faster physical recovery, but also better decision making in times of traumatic experience.
United States flood victims were asked if they would consider using a vaccine that would protect them from disease.
People who were optimistic about their future were also more likely to accept the vaccine, Prof Briley said.
