Table 1.

Circadian alteration of the pineal–hypothalamic–adrenocortical network A double magnetic storm is associated with lower pineal and higher hypothalamic time structure-adjusted MESORs (M) and circadian amplitudes (A) and a possible phase (φ) advance of the pineal circadian rhythm of melatonin (top half), and statistically significant day-to-day variability in M, A and φ of circulating corticosterone during the first study days including the magnetic storm vs. the last quiet days (bottom half). The extent to which this effect represents an infradian storm effect cannot be assessed because of the brevity of the series and the lack of controls.

Geomagnetics (condition)	Sampling(days of study)	M	A	φ	(A,φ)	(M,A,φ)
		Pineal melatonin (pg per tissue)
Stormy	1–2*	796.8	722.2	−288
Quiet	6–7	1052.9	1024.0	−309
P		0.021	0.051	0.054	0.020	0.006
		Hypothalamic melatonin (pg/tissue)
Stormy	1–2*	11.87	10.52	−258
Quiet	6–7	6.48	4.92	−271
P		0.005	0.033	0.521	0.129	0.016
		Circulating corticosterone† (log10%)
Stormy	1	1.83	0.41	−209
	2	2.02	0.25	−183
	3	1.78	0.17	−231
P		<0.001	0.066	0.130	0.040	0.001
Quiet	5	1.91	0.31	−209
	6	2.02	0.23	−235
	7	2.01	0.23	−196
P		0.410	0.754	0.439	0.652	0.643

^*Results complicated by novelty effect. Difference in MESOR between days 1–2 and 6–7 remains demonstrable for both pineal and hypothalamic melatonin after log_l0-transformation of the data (to normalize their distribution).

^†Data expressed as % of mean in rats of each sex separately, pooled and log₁₀-transformed.