Activation of brain receptors in its pleasure centre may serve as a future treatment to improve motivation for physical activity in postmenopausal women, a new study has revealed.

The brain's pleasure centre is a hotspot in the brain that processes and reinforces messages related to reward, pleasure, activity and motivation for physical exercise.

'Postmenopausal women are more susceptible to weight gain and health issues. This is especially frustrating for women who already are dealing with significant changes to their bodies. We found that the decrease in physical activity that leads to weight gain may be caused by changes in brain activity," said Victoria Vieira-Potter, Assistant Professor at the University of Missouri in a statement.

The researchers compared the physical activity of rats that were highly fit to rats which had lower fitness levels. They studied the rats' use of running wheels set up in the cages before and after the rats had their ovaries removed.

They also examined gene expression changes of dopamine receptors within the brain's pleasure centre.

The high-fit rat group had more activity in the brain's pleasure centre, which correlated with greater wheel running before and after the loss of ovarian hormones.

However, the high-fit rats still saw a significant reduction in wheel running after their ovaries were removed.

This reduction in wheel running also correlated significantly with a reduction in their dopamine signaling levels, indicating that the brain's pleasure centre could be involved, suggested the research.

'We found that in both groups of rats, the hormonal changes from menopause led to changes in the brain that translated to less physical activity. The findings confirm previous evidence in humans and rodents that weight gain that occurs after menopause is likely due to decreased overall physical activity rather than increased energy intake from diet,' added Vieira-Potter.