Pleasurable activity, whether food or sex, reduces stress by inhibiting anxiety responses in the brain according to researchers at the University of Cincinnati.
Experiments designed by Yvonne Ulrich-Lai, research assistant professor, James Herman, director of the Laboratory of Stress Neurobiology at UC, and colleagues also indicated that the reduced-stress effects continued for at least seven days, suggesting a long-term benefit.
"These findings give us a clearer understanding of the motivation for consuming 'comfort food' during times of stress," said Ulrich-Lai.
"But it's important to note that, based on our findings, even small amounts of pleasurable foods can reduce the effects of stress," he said.
The researchers provided rats twice daily access to a sugar solution for two weeks, then tested the rats' physiological and behavioral responses to stress.
Compared with controls, rats with access to sugar exhibited reduced heart rate and stress hormone levels while placed in ventilated restraint tubes and were more willing to explore an unfamiliar environment and socially interact with other rats.
Rats who were fed a solution artificially sweetened with saccharin showed similar reductions in stress responses, the researchers say, as did rats that were given access to sexually responsive partners.
Physiological responses to stress include activation of the hypothalamic-pituitary-adrenocortical (HPA) axis, regulated by the brain structure known as the basolateral amygdale (BLA).
Rats exposed to pleasurable activities, such as tasty foods and sex, experienced weakened HPA axis responses to stress, the researchers found.
The study was published online Nov. 8, 2010 in the official journal of the National Academy of Sciences.