Send to

Choose Destination
Brain Res. 1997 Jun 6;759(1):166-70.

Exposure to long summer days affects the human melatonin and cortisol rhythms.

Author information

Institute of Physiology, Academy of Sciences of the Czech Republic, Prague.


Exposure of 8 human subjects in summer to a natural 16 h bright light photoperiod phase advanced the morning salivary melatonin decline and cortisol rise and shortened the nocturnal melatonin signal by 2 h relative to the winter patterns of the same subjects followed under a combined artificial and natural light 16 h photoperiod. The data suggest that summer days experienced from sunrise till sunset and not winter days with a combined artificial and natural light long photoperiod evoke a true long day response of the human circadian system.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center