Table 4.

Summary of animal research focusing on HPA (hypothalamic-pituitary-adrenal) axis activity.

No.	Strain	Sex	Age	Physical Activity	Stress Model	Main Outcome	Reference
1	C57BL/6	male	2 months	voluntary wheel running	restraint stress	modulation of serum CORT level, increased BDNF protein level in the hippocampus	[5]
2	C57BL/6J	male	6 weeks	voluntary wheel running	restraint stress	reduced CORT response duration; increased adrenal sensitivity	[109]
3	C57BL/6	N/A	8 weeks	voluntary wheel running	social stress (housing conditions)	increased hippocampal expression of glucocorticoid receptor (Nr3c1), correlated with a down-regulation of miR-124	[111]
4	Wistar and Sprague–Dawley	male	N/A	treadmill	social stress	decreased serum CORT levels induced by stress; alleviated behavioural consequences of stress	[108]
5	Sprague–Dawley	male	2 months	voluntary wheel running	low-intensity stressors	reduced HPA responses to stressors	[104]
6	Sprague–Dawley	female	40 days	treadmill	restraint stress	augmented NE decrease in the amygdala, hippocampus, and LC after which modulate the regulation of ACTH	[110]
7	Wistar	male	2 months	voluntary wheel running	repeated noise stress	regulation of CRF and BDNF expression in several brain regions	[112]
8	Wistar	male	3 months	swimming	chronic social isolation or immobilization or cold (4 °C)	enhanced GR and Hsp70 levels in the hippocampus and brain cortex	[113]
9	Fischer F344	male	8–9 weeks	voluntary wheel running	tail-shock stress	facilitated induction of HSP7 in the brain	[114]

ACTH—adrenocorticotrophin; CORT—corticosterone; CRF—corticotropin-releasing factor; GR—intracellular glucocorticoid receptor; Hsp70—heat shock protein 70; LC—locus coeruleus; NE—norepinephrine.