The Hormonal Response of Women During Sub-maximal and Maximal
Exercise There are successions of physiological responses that
occur due to exercise, including the hypothalamic-pituitary-
adrenal (HPA) axis and autonomic nervous system activation. The
stimulation of the HPA axis and the sympathetic nervous system
secretes hormones that maintain the demands of muscles during
exercise (Galliven 1997, Singh 1998). Activation of the HPA axis
is demonstrated by the increase in elevated plasma levels of
adrenocorticotropin (ACTH) and cortisol (Singh, 1999). According
to Singh et al (1999), there is a well-documented rise in ACTH
in the early morning, which leads to relatively high cortisol
levels at this time rather than in the evenings. However,
Galliven (1997) found that metabolic and pituitary-adrenal
response to either high- or moderate-intensity exercises are not
effected in the AM or PM, despite the high levels of ACTH in the
mornings. DeSouza (1991) found that both eumenorrheic and
ammenorrheic athletes demonst