By Mike Cherney The Daily Northwestern

Adults who go to sleep at night feeling sad, lonely or depressed wake up the next day with higher levels of a hormone that provides an energy boost to overcome negative feelings, according to a Northwestern study published earlier this month.

But abnormally high levels of the hormone, cortisol, have also been linked to obesity and other disorders, said Emma K. Adam, an assistant professor of human development and social policy at NU who was also the study’s lead author.

Cortisol levels are supposed to be high upon waking, increase slightly after waking up and then decline steadily until bedtime. But when a person wakes up after feeling depressed or sad the night before, the body produces more of the hormone to boost energy to meet all the demands of the coming day.

In the study, which was published in the Proceedings of the National Academy of Sciences, Adam studied 158 adults between the ages of 58 and 68. Each participant measured their cortisol levels three times a day for three days – upon waking up, 30 minutes after waking up and at bedtime. They also filled out a diary entry in the evenings to document their emotions.

Adam found that the people studied who went to bed feeling sad or lonely had higher cortisol levels upon waking up. And if stressful experiences occurred during the day, cortisol levels remained high at bedtime.

“Others have studied cortisol, but they have looked at average levels across several days,” said Adam, who is also a member of Cells to Society: The Center on Social Disparities and Health at the Institute for Policy Research. “What we’ve demonstrated in this study is that changes in experience from day to day are related to day-to-day changes in this hormone.”

Adam also said the body seems to “run out” out of cortisol if it has been producing high levels of the hormone for a long time. Such artificially low levels of cortisol can make a person feel emotionally fatigued and could also lead to other physiological disorders.

The bottom line, Adam said, is that although cortisol can help a person overcome negative feelings in the short-term, being sad or depressed for a long period of time can be detrimental to one’s health since it can cause abnormal levels of the hormone.

“Some people might argue that you should do something to change the stress hormone level, like take a pill, but the real message is that if you’re feeling a lot of these negative emotions you should do something about your experiences,” she said. “If something is unpleasant to you emotionally, and it happens to you frequently or chronically, it’s potentially risky physiologically.”

Elissa Epel, an assistant professor of psychiatry at the University of California, San Francisco, who is not connected to the study, said the research shows that day-to-day changes in cortisol levels are not totally random.

“Researchers have always known there is great day-to-day variability, making it necessary to measure cortisol across several days to detect stable patterns,” she wrote in an e-mail. “This study suggests that much of this variability is meaningful.”

Adam’s study also revealed differences in cortisol patterns among different ethnic groups. Minorities, such as blacks or Latinos, were more likely to have higher cortisol levels at bedtime than whites. Adam suggested that this could show that minorities on average have more stressful days and could be a reason for different health problems in minority communities.

Adam said she is working on future cortisol studies which will analyze a larger and more diverse group of people and investigate moment-to-moment changes in cortisol levels.

Reach Mike Cherney at [email protected].