Menstrual Cycle

A female athlete's performance may depend on the phase of the menstrual cycle she is in. The menstrual cycle ranges from 24 to 35 days and comprises of three phases: menstrual phase (menses), preovulatory phase and the postovulatory phase. The menstrual phase is the periodic discharge of 25 to 65ml of blood, tissue fluid etc. and lasts for approximately 3 to 7 days.

Example of the phases of 28 day menstrual cycle:

Days 1 to 5 Days 6 to 13 Day 14 Days 15 to 28
Menstruation phase Preovulatory phase Ovulation Postovulatory phase

The effect of sport

Physically active women increase their chances of changes to their menstrual cycle. These include irregular cycles (oligomenorrhea) or complete cessation of the cycle (amenorrhea). In the general population, amenorrhea occurs in 2 to 5% of women of reproductive age, whereas for women participating in sport it can be as high as 40%.

Other factors

All women need to be aware that exercise is not the only factor that can result in oligomenorrhea or amenorrhea. The other factors are a high stress level, body weight and body composition (% body fat level below 20%).

Athletes are prime candidates for oligomenorrhea or amenorrhea as they are likely to experience:

  • heavy training loads
  • high stress levels from trying to manage the training program with work and family life and the pressures of competition
  • as a result of the training, body weight may reduce and the fat level may fall below 20% for some months

Consequences

Amenorrhea reduces the body's capacity to absorb calcium, decreases bone density and increases the risk of musculoskeletal injury in vigorous exercise.

Impact on training

The hardest time to race efficiently, for athletes experiencing a menstrual cycle, is during the week before menstruation and a week after ovulation (Tracy Williams Ph. D 1993). At these times increased levels of progesterone simulate the brain's respiratory centre increasing ventilation rates (progesterone is also linked to the mood swings). Athletes use breathing rate as an indicator of exercise intensity so exercise can tend to feel harder at these times.

The time of maximum efficiency for athletes experiencing a 28 day menstrual cycle might be pre-ovulation (days 9 to 12) or post-ovulation (days 17 to 20).

Reference Papers

  • "Menstrual Cycle Phase and Running Economy", Medicine and Science in Sports and Exercise, vol 25(5), p.S74, 1993
  • "Blood lactate concentrations and lactate threshold during menstrual cycle phases of distance runners", Medicine and Science in Sports and Exercise, vol 25(5), p.S144, 1993
  • "The menstrual cycle and exercise: performance, muscle, glycogen, and substrate responses," International Journal of Sports Medicine, vol. 10(4), pp. 264-269, 1989
  • "Respiratory Drives and exercise in menstrual cycles of athletic and non-athletic women," Journal of Applied Physiology, vol. 50, pp. 1300-1305, 1981
  • Barrow and Saha, "Menstrual irregularity and stress fractures in collegiate female distance runners", American Journal of Sports Medicine, 1998, vol. 18, pp 209-216
  • Myburgh and co-workers, "Low bone mineral density at axial and appendicular sites in amenorrhoeic athletes", Medicine and Science in sports and exercise, vol.25, no. 11, pp 1197-1202)
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Associated Pages

The following Sports Coach pages should be read in conjunction with this page:

Associated Books

The following books provide more information related to this topic:

  • Principles of Anatomy and Physiology, G.J. Tortora et al., ISBN 0 06 046704 5
  • Strength Training Anatomy, F. Delavier, ISBN 0 7360 4185 0
  • Atlas of Skeletal Muscles, R.J. Stone et al., ISBN 0 697 13790 2
  • The Muscle Book, P. Blakey, ISBN 1 873017 00 6
  • Advanced Studies in Physical Education and Sport, P Beashel et al., ISBN 0 17 4482345
  • Physical Education and the Study of Sport, B. Davis et al., ISBN 0 7234 31752
  • Essentials of Exercise Physiology, W.D. McArdle et al., ISBN 0 683 30507 7
  • Physical Education and Sport Studies, D. Roscoe et al., ISBN 1 901424 20 0
  • The World of Sport Examined, P. Beashel et al., ISBN 0 17 438719 9
  • Advanced PE for Edexcel, F. Galligan et al., ISBN 0 435 50643 9
  • Examining Physical Education, K. Bizley, ISBN 0 435 50660 9
  • Sport and PE, K Wesson et al., ISBN 0 340 683821
  • PE for you, J. Honeybourne, ISBN 0 7487 3277 2

Keywords: menstrual, cycle, phase, sport, training, amenorrhea, oligomenorrhea, physiology, exercise, anatomy, level, muscle, preovulatory, postovulatory, range, athlete, comprises, women, medicine, ovulation, physical, education