Effects of follicular phase exercise on luteinizing hormone pulse characteristics in sedentary eumenorrhoeic women

OBJECTIVE Current studies reveal little regarding the Inception of exercise-induced LH changes during physical training. This study aimed to assess the susceptibility of the hypothalamic–pituitary axis to the acute physical stress of exercise in untrained, physically inactive women. The acute effects of submaximal endurance exercise upon the pulsatile LH secretion in the follicular phase were compared with those accompanying leisurely strolling for a similar time period. SUBJECTS All subjects were eumenorrhoelc, as determined by biphasic temperature patterns, detection of the urinary LH surge, and mid-luteal serum progesterone levels. Subjects were not physically active and had little history of strenuous exercise ( V o 2 max = 38·0 ± 1·8) (mean ± SEM) ml/kg/min). DESIGN All women completed a 13·5-hour pulsatility test which included three consecutive 20-minute runs on a treadmill at 50, 60 and 70% of the subjects’maximum oxygen uptake ( n = 16). Six of these same subjects completed a separate test on another occasion in which one hour of leisurely strolling was substituted for exercise. Blood was sampled every 10 minutes via an indwelling cannula for 4·5 hours before and 8 hours after one hour of exercise and or strolling. MEASUREMENTS A pulse algorithm (Pulsar) was used to quantify LH pulse characteristics. RESULTS Exercise produced no significant effects upon LH pulse frequency or mean serum LH concentration. However, exercise of moderate intensity caused a significant increase in LH pulse amplitude ( P < 0·05). Strolling produced no significant changes in LH secretion. CONCLUSION Acute exercise of moderate intensity in the follicular phase of untrained women is an insufficient stimulus to inhibit the GnRH pulse generator in the post-exercise period, yet may produce a slight stimulatory effect on the amount of LH released per pulsePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73507/1/j.1365-2265.1994.tb02794.x.pd

Allostatic load, perceived stress, and health: a prospective study in two age groups. [in issue: Biobehavioral Stress Response Protective and Damaging Effects]

Overactivity of the hypothalamus-pituitary-adrenal axis (HPAA) has been observed in the presence of acute stress and, under chronic conditions, in disorders such as depression and anorexia nervosa as well as in cardiovascular and metabolic disorders. However, there may be other stress-related disorders (fatigue, pain, etc) that seem to be associated with mild hypocortisolism. This suggests that two major subtypes of the HPAA response to stress need to be discriminated. In this study, we investigated 76 subjects with and without hypocortisolism, respectively, over a 1-year period. Surprisingly, hypocortisolemic subjects had a lower allostatic load but they scored higher on measures of depression, perceived stress, and physical complaints. We propose a protective role of the hypocortisolemic stress response on cardiovascular and metabolic disorders, particularly in the elderly