Working out and reproductive health

I used to love those TV commercials that showed women riding horses, running around in white bathing suits, and frolicking in fields of flowers after having been privy to the majickal secret of the tampon. The right kind of “sanitary protection” was your ticket to freedom, baby. Not only would you too be able to prance happily along beaches but would also be shot in soft focus with flattering light and butterflies around your head. Interestingly, although commercials promoted a vision of feminine freedom through consumption, many myths remained around just what women were capable of doing during and after their menses and pregnancies.

Despite the obvious numerical fact that at any one time, some female athlete must be getting her period, and despite the fact that Olympic medals have been won by pregnant or menstruating athletes, there is a pervasive fallacy in some circles about women’s “problems”. In the 1800s, although it was conveniently forgotten that huge numbers of women already performed strenuous manual labour on the farms and in the factories, the prevailing medical wisdom about exercise for women was that during the menstrual period and pregnancy women must be sequestered from ALL activities. It should be noted, however, that during this time period it was also commonly held by medical professionals that studying mathematics would cause the uterus to shrivel.

Normal female bodily functions have been pathologized as “conditions” or “diseases”, which affects the way we think about them. The truth is, these functions and processes have been around for quite some time and are showing no signs of disappearing. While some, like pregnancy, may require a little extra planning and exercise modification, in general there is no reason whatsoever to believe that weight training and other exercise, done in moderation, are problematic.

Need to hear an “official” opinion on this instead my yammering? Drs. Clapp and Little write in the American Journal of Obstetrics and Gynecology:

[A]t all points in a woman’s life the overall effect of regular exercise to appetite appears to be beneficial rather than harmful and in the absence of other stressors exercise performance must significantly exceed usual recreational levels to have an adverse effect on any aspect of a woman’s reproductive life. Therefore even in elite athletes abnormalities of any part of the reproductive process (puberty, menstrual cyclicity, pregnancy, lactation, and menopause) should not be attributed solely to exercise without complete evaluation.

In other words, you go girl.

[Clapp JF 3rd; Little KD. “The interaction between regular exercise and selected aspects of women’s health”. Am J Obstet Gynecol, 173(1):2-9 1995 Jul]

menstruation | amenorrhea | pregnancy | menopause

menstruation

I don’t know about you but I used to use the “I’m getting my period” excuse to get out of gym class a lot. Frankly, I would have used the “my dog ate my gym clothes” excuse if I had known there was a chance in hell of it working. This was OK until I encountered a real hardass gym teacher in Grade 9 who insisted that violent menstrual cramps were figments of our imaginations and she expected to see our pathetic bleeding carcasses on the track, same as usual. Obviously she was a woman for whom Advil was just a headache remedy and not Holy Cramp Communion. Really, there has to be some kind of happy medium.

Anyway, plenty of studies have been done that try to show some decrease in performance during menstruation. Whenever some decrease is actually found it is difficult to sufficiently isolate the variable such that the decrease can be explicitly linked to menstruation. In other words, there is NO conclusive clinical proof that getting your period negatively affects your athletic performance. In addition, there is a great deal of individual variation among women.

Results vary wildly from study to study, which shows that individual physical variation combined with psychological factors around menstruation produces highly diverse outcomes with regard to performance during menstruation. Frinstance:

• No change to cardio capacity
  • [Smekal, G, et al. Menstrual cycle: no effect on exercise cardiorespiratory variables or blood lactate concentration.Med Sci Sports Exerc. 2007 Jul;39(7):1098-106]
• Some elevated risk of knee injury, though this varies by menstrual phase
  • [Hewett TE, et al. Effects of the menstrual cycle on anterior cruciate ligament injury risk: a systematic review. Am J Sports Med. 2007 Apr;35(4):659-68.]
• In a study of female athletes, “physical performance was not affected by the menstrual period and the pain decreased during the training and competition.”
  • [Kishali NF, et al.Effects of menstrual cycle on sports performance. Int J Neurosci. 2006 Dec;116(12):1549-63]

And this abstract is worth posting in entirety:

This article reviews the potential effects of the female steroid hormone fluctuations during the menstrual cycle on exercise performance. The measurement of estrogen and progesterone concentration to verify menstrual cycle phase is a major consideration in this review. However, even when hormone concentrations are measured, the combination of differences in timing of testing, the high inter- and intra-individual variability in estrogen and progesterone concentration, the pulsatile nature of their secretion and their interaction, may easily obscure possible effects of the menstrual cycle on exercise performance. When focusing on studies using hormone verification and electrical stimulation to ensure maximal neural activation, the current literature suggests that fluctuations in female reproductive hormones throughout the menstrual cycle do not affect muscle contractile characteristics. Most research also reports no changes over the menstrual cycle for the many determinants of maximal oxygen consumption (VO2max), such as lactate response to exercise, bodyweight, plasma volume, haemoglobin concentration, heart rate and ventilation. Therefore, it is not surprising that the current literature indicates that VO2max is not affected by the menstrual cycle. These findings suggest that regularly menstruating female athletes, competing in strength-specific sports and intense anaerobic/aerobic sports, do not need to adjust for menstrual cycle phase to maximise performance. For prolonged exercise performance, however, the menstrual cycle may have an effect. Even though most research suggests that oxygen consumption, heart rate and rating of perceived exertion responses to sub-maximal steady-state exercise are not affected by the menstrual cycle, several studies report a higher cardiovascular strain during moderate exercise in the mid-luteal phase. Nevertheless, time to exhaustion at sub-maximal exercise intensities shows no change over the menstrual cycle. The significance of this finding should be questioned due to the low reproducibility of the time to exhaustion test. During prolonged exercise in hot conditions, a decrease in exercise time to exhaustion is shown during the mid-luteal phase, when body temperature is elevated. Thus, the mid-luteal phase has a potential negative effect on prolonged exercise performance through elevated body temperature and potentially increased cardiovascular strain. Practical implications for female endurance athletes may be the adjustment of competition schedules to their menstrual cycle, especially in hot, humid conditions. The small scope of the current research and its methodological limitations warrant further investigation of the effect of the menstrual cycle on prolonged exercise performance.

[de Jonge, J. Effects of the menstrual cycle on exercise performance. Sports Med. 2003;33(11):833-51.]

However, that being said, many women find that there are cyclic changes in their strength, recovery, and athletic performance. In particular, anecdotal data suggests that during the premenstrual period, and often the first day or two of the menstrual period:

• pain perception increases  — you may feel achey, soreness from training may be more intense, joint pain may increase
• energy levels decrease; fatigue increases
• joint laxity increases; you may be more likely to experience joint pain and injury

Many women also find that their strength temporarily decreases, although exactly when this occurs varies from woman to woman.  In my case, I am weaker for a few days when my period starts. I noticed this years ago, and now take note of my menstrual cycle in my training journal. I simply schedule some recovery/light days to accommodate.

In terms of the effect of exercise on menstruation, no clinical evidence has been found to show that moderate regular exercise affects the cycle negatively. In the next section on amenorrhea, I point out some of the problems associated with heavy training and low bodyfat levels. The majority of women find that exercise alleviates many of the negative symptoms associated with premenstrual and menstrual discomfort.

amenorrhea

Amenorrhea is the clinical term for cessation of menstrual periods with possible related loss of ovulation. This is generally seen in women who train very heavily and/or have bodyfat below 12-15%; thus, athletes, bodybuilders, and models may all experience this condition. In essence, menstruation has ceased because the body does not feel that it has sufficient resources to nurture a fetus. Interestingly, there seems also to be a relationship between intense athletic training in young girls and delayed initial onset of menstruation, although the exact variables are hard to determine. It may be that lean girls are more athletically predisposed anyway, and the delay of menarche (onset of first menstruation) is merely an adjunct rather than a result.
One of the main concerns around amenorrhea is the concomitant loss of bone density. In other words, skeletal bone mineral loss has been observed to be related to lack of menstruation.

However, research has demonstrated that amenorrhea is not caused by low bodyfat per se. Women with relatively higher bodyfat levels can and do experience cessation of menstruation. Rather, it appears to be triggered primarily by a long-term negative energy balance, which can result in a low bodyfat. Energy balance is the relationship between calories in and calories expended. If a female athlete consistently maintains a negative energy balance for a long time (in other words, if she does not eat enough to fuel her activity), then this is what stimulates loss of menstruation, not a particular bodyfat level in and of itself. Indeed, female athletes and bodybuilders who are sensible about their nutrition and dieting practices may find that they do not lose their periods even though they get quite lean.

Recent research suggests that multiple hypothalamic-pituitary hormones and environmental factors such as stress and nutritional restriction are involved in regulating menstruation in active women.

Although some women who re-start menstruation can make some moderate gains back, it appears that long-term bone mineral loss related to amenorrhea is largely irreversible. With the increasing concern about osteoporosis in our society today, this is a critical concern for female athletes. Data is still sketchy on the bone density concerns of developing girls, although perhaps this problem in general might be somewhat alleviated by weight training, which is known to increase bone density. Along with the problem of bone mineral loss comes the problem of stress fractures. The possibility of stress fractures raises some important questions. Is, for example, the increased bone density of the marathon runner as compared to her sedentary colleague enough to withstand the actual activity of marathon running? At what point do the load-bearing exercises, which improve bone density, become too much load for the bone to handle?

Obviously there are more variables involved in the problem of amenorrhea and bone density loss. Diet, training, and other environmental factors are also significant considerations. However, amenorrhea as a long-term clinical state is highly undesirable in any case.

Sources:

Baker, E. and L. Demers. “Menstrual Status in Female Athletes: Correlation with Reproductive Hormones and Bone Density”. Obstet Gynecol 72:683-7, 1988.

Barrow, G.W. and S. Saha. “Menstrual Irregularity and Stress Fractures in Collegiate Female Distance Runners”. American Journal of Sports Med 16(3):209-16, 1988.

Broocks, A. et al. “Cyclic Ovarian Function in Recreational Athletes”. Journal of Applied Physiology, 68:2023-86, 1990.

Frisch, R.E. “Body Fat, Menarche, Fitness, and Fertility”. Human Reproduction 2(6):521-533, 1987.

Laughlin, G. et al. “Nutritional and Endocrine-Metabolic Aberrations in Women with Functional Hypothalamic Amenorrhea”. Journal of Clinical Endocrinology and Metabolism 83 (1): 25-32.

Miller, K. et al. “Decreased Leptin Levels in Normal Weight Women with Hypothalamic Amenorrhea: The Effects of Body Composition and Nutritional Intake.” Journal of Clinical Endocrinology and Metabolism 83 (7): 2309-2312, 1998.

pregnancy

Historically the question of what women should do during pregnancy was a highly class-based one. Upper- and middle-class European and North American women of previous centuries were kept in confinement and forced leisure. To be visibly pregnant was constituted as a bit of a social shame, and women were discouraged from appearing in public with the evidence of reproduction swelling their bellies (plus, it was kinda tough to fit into those corsets after a few months, although many women tried and subsequently did quite a bit of damage to themselves and the baby). However, being immobilized and enshrined in the house was a luxury not available to the majority of the female population. Most worked at some sort of manual labour right up until their delivery and still do (female Japanese pearl divers, for example, work in physically strenuous conditions and continue to do so until the point of delivery). Thus the question of what women can do during pregnancy reveals a lot of middle- and upper-class assumptions about what is appropriate for women at any time.

One of the important truisms about activity during pregnancy is that pregnancy is not the time to begin a strenuous exercise program. Don’t start German Volume Training or any kind of masochistic weight program. In fact, pregnancy is not the time to make any drastic physical changes. However, women who are already accustomed to regular activity and exercise generally find pregnancy no disruption to their normal routine.

The female body has had plenty of evolutionary time to adapt to the stress of pregnancy and compensates for the extra demand in a variety of ways. For example, oxygen consumption/aerobic capacity can increase up to 30% during pregnancy in nonexercisers and even more in women who exercise. In addition, strenuous exercise can be exceedingly uncomfortable in the last part of pregnancy, which is perhaps the body’s way of telling mom to lay off for a while till things get back to normal.

However, anecdotal and clinical evidence shows that fitter women tend to have easier pregnancies and shorter deliveries with fewer complications. Many women also find that exercise during pregnancy helps alleviate fatigue and keep energy levels up. In addition, exercise has been shown to reduce the gain of subcutaneous (under the skin) fat associated with extra caloric intake during pregnancy. Thus, regular and moderate exercise during pregnancy can have many positive effects.

One of the most typical problems encountered by pregnant women is back pain. Their centre of gravity shifts and extra weight is added over nine months. Women tend to slouch the shoulders and arch the lower back to compensate for these changes, which of course leads to discomfort. A strong abdominal column as well as a strong back gained through weight training before pregnancy can alleviate much of this problem.

Hormonal changes during pregnancy contribute to a softening and loosening of the connective tissues. This is done by the body so that it will be able to accommodate the stress of delivery. Women find that during their pregnancies it is easier to “pull” or “twist” things due to the joints putting up less resistance. Once again, weight training before pregnancy can help ensure that injury does not occur.

As I mentioned in the section on beginning to work out, rehydration is essential, at this time more than ever. Pregnant women are especially prone to overheating during exercise, so monitoring temperature, avoiding exercise in hot, humid environments, ensuring that there are mechanisms for body cooling (sweating, loosening of clothing, etc.), and drinking lots of water are key.

With regard to fetal effects, no detrimental effects have been shown in the babies of women who exercised during pregnancy. Birth weights were similar, rates of cesarean section the same, and general health of newborns was in normal range.
If you choose to exercise during pregnancy, here are a few guidelines to follow.

1. Monitor your nutritional needs. You will need extra calories and attention to a balanced diet.
2. Get adequate rest. This is true for any weight training program and more so during this period.
3. Make exercise regular. Infrequent and/or irregular exercise can result in injury or fatigue.
4. Be prepared to make modifications in your program as you need to. This is not the time to push the limits of your endurance or strength.
5. As part of your regular medical checkups, have your doctor advise you on possible changes to your body (e.g. cervical dilation) that may require you to modify your program. Ensure that you keep your doctor up to date on what kinds of activities you’re engaging in.
6. Be careful about joint and connective tissue injury. Make sure you have an adequate warmup and cooldown as part of your workout.
7. Don’t take any supplements during pregnancy or breastfeeding other than a good-quality whey protein and a multivitamin (your doctor may recommend additional vitamin supplementation). Obviously, use of anabolic substances are a huge no-no at this time.

See the other articles on pregnancy and postpartum training in this section.

There is a bit of folk wisdom which suggests that women should not engage in exercise after having had a baby. There are dire predictions about souring the milk and so forth, having your uterus fall out, or heaven knows what. This is, for lack of a clinical term, crap. Studies have shown no increase in acidity of breast milk after mom’s exercise. Regular postnatal exercise reduces or eliminates most of the unpleasant postpartum symptoms of physical and mental stress, depression, and so forth, as well as promoting a faster recovery. Furthermore, children of moms who exercised before, during, and after pregnancy were shown to be relatively leaner themselves five years later.

Sources:

Margolis RS. “Exercise and pregnancy”. Md Med J, 45(8):637-41 1996 Aug
Sternfeld B; Quesenberry CP Jr; Eskenazi B; Newman LA. “Exercise during pregnancy and pregnancy outcome”. Med Sci Sports Exerc, 27(5):634-40 1995 May

Clapp JF 3rd; Little KD. “Effect of recreational exercise on pregnancy weight gain and subcutaneous fat deposition”. Med Sci Sports Exerc, 27(2):170-7 1995 Feb

TanJi J. “Exercise during pregnancy and pregnancy outcome”. Clin J Sport Med, 5(4):267 1995 Oct

Hale RW; Milne L. “The elite athlete and exercise in pregnancy”. Semin Perinatol, 20(4):277-84 1996 Aug

Lee G. “Exercise in pregnancy”. Mod Midwife, 6(8):28-33 1996 Aug

Schramm WF; Stockbauer JW; Hoffman HJ. “Exercise, employment, other daily activities, and adverse pregnancy outcomes”. Am J Epidemiol, 143(3):211-8 1996 Feb 1

Clapp JF 3rd. “Morphometric and neurodevelopmental outcome at age five years of the offspring of women who continued to exercise regularly throughout pregnancy”. J Pediatr, 129(6):856-63 1996 Dec

Pivarnik JM. “Cardiovascular responses to aerobic exercise during pregnancy and postpartum”. Semin Perinatol, 20(4):242-9 1996 Aug

Veille JC. “Maternal and fetal cardiovascular response to exercise during pregnancy”. Semin Perinatol, 20(4):250-62 1996 Aug

Sternfeld B. “Physical activity and pregnancy outcome. Review and recommendations”. Sports Med, 23(1):33-47 1997 Jan

Koltyn KF; Schultes SS. “Psychological effects of an aerobic exercise session and a rest session following pregnancy”. J Sports Med Phys Fitness, 37(4):287-91 1997 Dec

Horns PN; Ratcliffe LP; Leggett JC; Swanson MS. “Pregnancy outcomes among active and sedentary primiparous women”. J Obstet Gynecol Neonatal Nurs, 25(1):49-54 1996 Jan
Kardel KR; Kase T. “Training in pregnant women: effects on fetal development and birth”. Am J Obstet Gynecol, 178(2):280-6 1998 Feb

Dumas GA; Reid JG. “Laxity of knee cruciate ligaments during pregnancy”. J Orthop Sports Phys Ther, 26(1):2-6 1997 Jul

Clapp JF 3rd; Little KD. “The interaction between regular exercise and selected aspects of women`s health”. Am J Obstet Gynecol, 173(1):2-9 1995 Jul

Carey GB; Quinn TJ; Goodwin SE. “Breast milk composition after exercise of different intensities”. J Hum Lact, 13(2):115-20 1997 Jun.

menopause

Surprisingly, there have been few studies done on menopausal women and exercise. I suspect as the boomers continue to age, we will see much more interest in the subject. Most research has been done on pre- or post-menopausal women, or simply midlife women as an aggregate age group without specific regard to reproductive status. The problem with studying menopausal women as a group is that it is difficult to distinguish the particularities of menopause from the particularities of aging, as well as the individual variation in terms of body weight, physical activity levels, genetic propensities, nutrition, etc. As one writer notes, “Much of what has been considered aging in the past is considered functional disuse today.”[1]

The main concern for menopausal and postmenopausal women is the drop in estrogen levels that is associated with bone density loss. This is especially problematic for those women who may have been amenorrheic in their youths, since there is likely some bone density loss which has already taken place.

Weight training, however, has been shown to have very beneficial effects irrespective of age. Obviously a menopausal woman isn’t going to respond in the same way as a teenage girl, but the positive consequences of weight training are undeniable. Within every age group, active women fare better than inactive women in just about every test. Some studies show that exercise can reduce and/or delay much of the symptomology (hot flashes, anxiety, etc.) associated with menopause.

Frinstance, one study that compared exercising vs non-exercising women over three years found that exercisers got stronger and improved bone density, body composition (waist circumference, waist-to-hip ratio), blood lipids (total cholesterol, triglycerides), and menopausal symptoms (insomnia, migraines, mood changes). The non-exercisers got weaker. [Kemmler et al, “Exercise Effects on Menopausal Risk Factors of Early Postmenopausal Women: 3-yr Erlangen Fitness Osteoporosis Prevention Study Results.” Medicine & Science in Sports & Exercise. 37(2):194-203, February 2005.]

Another interesting study on the nutritional requirements of older women, done by Wayne Westcott (an expert in the field of older athletes) and coauthors, found that women given appropriate resistance training and postworkout nutrition gained a surprising amount of muscle and lost a surprising amount of body fat. (I had the pleasure of speaking to Wayne in person about this one. Apparently everyone was floored.) Full study

If one has been inactive, menopause is a good time to become active. It’s never too late to begin to strength train and engage in regular exercise. Excess body fat is associate with a host of later-life problems such as heart disease and diabetes. As I have shown in the other articles, increasing one’s muscle mass contributes dramatically to a decrease in injuries and chronic problems, as well as to a loss of excess body fat. If you have been inactive for a period of time, make sure to see your doctor for a complete physical before you begin.

One important point for aging women: in the calculation of body fat percentages, the same actual caliper measurement (say, 15 mm) will mean different body fat percentage readings depending on age. This is due to inter-abdominal fat deposition with age. In other words, the older you get, the more fat you accumulate on your internal organs as opposed to beneath your skin (subcutaneous fat). Thus the “healthy” range of percentages increases with numerical age.

[1] Peters, Gregory. “Conditioning the Aging Female”. The Athletic Woman, ed. Arthur Pearl. USA: Human Kinetics Publishers and the American Orthopedic Society for Sports Medicine, 1993.