Under stress, the adrenal glands secrete extra dehydroepiandrosterone (DHEA). In one study, researchers measured how different levels of DHEA affected performance under stress.
Researchers checked DHEA blood levels in 41 healthy soldiers the day before the men began a month-long combat diver training course. Men with higher DHEA levels performed better during the final nighttime underwater navigation test than men with lower levels. Underwater navigation relies on an area of the brain called the hippocampus, which has stress receptors DHEA regulates.
Researchers believe the findings help explain why soldiers handle stress differently, and that compounds like DHEA may help protect them in the future.