Heightened cortisol response to exercise challenge in women with functional hypothalamic amenorrhea.

BACKGROUND

Functional hypothalamic amenorrhea is characterized by anovulation caused by reduced gonadotropin-releasing hormone drive and is associated with hypercortisolemia that has been linked to heightened hypothalamic-pituitary-adrenal reactivity to common psychological and metabolic challenges.

OBJECTIVE

We hypothesized that women with functional hypothalamic amenorrhea would display greater cortisol responses to exercise challenge than ovulatory women with eumenorrhea.

STUDY DESIGN

We completed a cross-sectional comparison of 9 women with functional hypothalamic amenorrhea and 11 women with eumenorrhea who were of reproductive age, who weighed 90-110% ideal body weight, who did not exercise excessively, and who had no formal psychiatric diagnosis. Subjects completed a 20-minute submaximal exercise challenge using a cycle ergometer in a research exercise laboratory. Heart rate and circulatory cortisol, glucose, and lactate were measured at 10-minute intervals before, during, and after the exercise challenge.

RESULTS

Baseline (t= -10 minutes) cortisol, glucose, lactate, and heart rate were comparable between groups. Glucose levels rose modestly during exercise by 2.9% in women with eumenorrhea (P=.4) but declined by 10.6% in functional hypothalamic amenorrhea (P<.03). The nadir in glucose levels in functional hypothalamic amenorrhea occurred at the end of the 20-minute exercise challenge (t= +20 min). Lactate levels rose comparably in both groups (P<.01). Heart rate increased significantly with exercise in both groups (P<.01), but the increase was smaller in subjects with functional hypothalamic amenorrhea (P<.01). Cortisol levels increased during the exercise challenge in both groups (P<.01) and peaked 10 minutes after the exercise ended (t= +30 min). At peak, subjects with functional hypothalamic amenorrhea displayed higher cortisol levels (147±22 [standard error of the mean] ng/mL) than women with eumenorrhea (96±12 ng/mL; P=.05). The mean percent increase over baseline was 62% in women with eumenorrhea and 92% in functional hypothalamic amenorrhea.

CONCLUSION

The heightened cortisol response to exercise in women with functional hypothalamic amenorrhea was associated with a decline in blood glucose level that was not observed in women with eumenorrhea. Women with functional hypothalamic amenorrhea appear to be more reactive at the endocrine level to the metabolic demand of exercise. Submaximal challenge unmasks underlying stress sensitivity in women with functional hypothalamic amenorrhea and highlights the importance of the use of psychological interventions for stress reduction in this population.