Exercise intensity. An important factor in the etiology of menstrual dysfunction?

• Published in: Scandinavian journal of medicine & science in sports 1996-12, Vol.6 (6), p.329-336
• Main Authors: Tomten, S. E., Høstmark, A. T., Strømme, S. B.
• Format: Article
• Language: English
• Subjects: Anaerobic Threshold; Analysis of Variance; athletic amenorrhea; Biological and medical sciences; Case-Control Studies; Estradiol - blood; Exercise - physiology; exercise intensity; Female; Female genital diseases; female runners; Follow-Up Studies; Gynecology. Andrology. Obstetrics; Heart Rate; Humans; marathon; Medical sciences; menstrual dysfunction; Menstruation Disturbances - etiology; Non tumoral diseases; Oxygen Consumption; Physical Education and Training - methods; Physical Endurance - physiology; reproduction anaerobic threshold; Running - physiology; serum estradiol; women
• ISSN: 0905-7188; 1600-0838
• DOI: 10.1111/j.1600-0838.1996.tb00102.x

The objective of this case control study was to compare training activity in female long distance runners with irregular (IR, n=13) and regular (R, n=16) menstrual function, especially with regard to exercise intensity. Serum estradiol concentration during the follicular phase was considered normal in the R subjects (31±6 pg/1). In contrast, the IR runners were clearly hypoestrogenic (11±1.6 pg/1). The two groups had similar Vo2max' anaerobic threshold (AT) and maximal heart frequency (HFmax). In both groups AT was found at 88% of HFmax' The two groups had similar mean race results in half marathons during the previous year. The number of running contests was, however, twice as high in the IR group. A light portable pulse recorder was used to monitor heart rate during 1 week of regular training activity, and during a controlled high intensity work‐out. During a week with normal training activity, an equal amount of training at high intensity levels (>85% HFmax) was performed by the two groups. The amount of training at lower intensities (