Introduction: Several studies reported DHEA relations to memory and cognition improvement. An anti-cortisol action may contribute to those relations. The effect of working memory (WM) on DHEA levels is unknown. We studied DHEA and cortisol reactivity in humans after a WM stimulus with simultaneous distraction.
Subjects and methods: Twenty eight healthy female volunteers (1826 years old) were presented a well-established auditory-visual distraction task protocol. Subjects performed one task with working memory (WM) load (WM1) and other without (WM0), 120 min apart, with counterbalanced order across subjects. Each task consisted of 500 trials (15 min), all composed by a task irrelevant sound (80% standard; 20% novel) followed by the visual stimulus that the subject had to classify. Salivary DHEA and cortisol were measured before each task (0 min) and at 30 and 60 min.
Results: DHEA raised after the second task (P=0.016), more with WM1 load (190±83 at 0 min vs 290±206 pg/ml at 30 min, P=0.045) and cortisol declined after WM0, when it was the first task (1290 pg/ml at 0 min vs 930 pg/ml at 30 min vs 620 pg/ml at 60 min, P<0.05) so that DHEA and cortisol levels were higher when WM1 was the second task (DHEA: P=0.022, cortisol: P=0.004). Cortisol:DHEA ratio was lower in the second task (P=0.001) and decreased after both tasks performance (P=0.036).
Discussion: Under distraction, higher DHEA levels were found after the performance of two consecutive cognitive tasks. DHEA raised and cortisol did not decline after WM load when it was the second task, suggesting that consecutive cognitive tasks and WM load may raise DHEA and prevent cortisol decrease. DHEA increase with WM load contributed to lower cortisol:DHEA ratio after that task. Previous studies related higher DHEA levels with memory enhancement. The present results suggest that cognitive tasks and WM load may also be a stimulus against DHEA decay.