Running and Zumba classes remain no more exciting after menopause hits a woman.
Beside the general hormonal changes, scientists have struggled to offer a specific reason for this, reports the Daily Mail.
A team at the University of Missouri has identified a link between ovarian hormones and dopamine levels in the brain that make exercise feel so good. This can lead to a new study to help women treat their lethargy.
"Postmenopausal women are more susceptible to weight gain and health issues," said Dr Victoria Vieira-Potter, specialised in nutrition and exercise physiology at MU.
"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," she added.
The menopause, which tends to strike by the early 50s, can cause mood swings, depression and anxiety. In many cases, it also affects a woman's drive to move, and many women gain weight during this time.
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To examine this side effect, Dr Vieira-Potter's study tracked the physical activity of rats, some of which were physically fit and some that were not.
First, they monitored their fitness levels and the level of activity in the pleasure center of their brains.
Then they removed their ovaries to mimic the effects of menopause, when women stop producing estrogen in such significant quantities.
Both groups, no matter how physically active they were before, showed dramatic reductions in their motivation to run on a running wheel.
All the rats also experienced a drop in the amount of dopamine in the pleasure center of their brain.
It suggests that the hormonal changes experienced during menopause could impact the brain and could be the process that hampers physical activity.