MAGNETIC EFFECTS ON HORMONES. “It is hypothesized that the cryptochrome compass system is mediating stress responses more broadly across the hypothalamic–pituitary–adrenal (HPA) axis (including alterations to circadian behaviour) in response to changes in the GMF. It is therefore proposed that GMS lead to disorientation of hormonal systems in animals and humans, thus explaining the effects of GMS on human health and behaviour.” (GMS = geomagnetic storms; GMF = geomagnetic field).
http://rspb.royalsocietypublishing.org/content/early/2012/03/12/rspb.2012.0324.short