EXERCISE AND QUALITY OF LIFE
Review article
Volumen 5, No. 2, 2013,
11-19
UDC: 796.015.86:612.662
MENSTRUAL CYCLE AS AN OBSTACLE TO ACHIEVING
MAXIMAL SPORT RESULT
Milan P. Mladenović
Health Centre, General Hospital Vranje
Vedrana V. Karan*
Aleksandar V. Klasnja, Jelena Z. Popadic Gacesa, Otto F. Barak
Department of Physiology, Medical Faculty, University of Novi Sad, Serbia
Olivera R. Markovic
Department of Physics, Faculty of Sciences, University of Novi Sad, Serbia
Abstract
Each woman has different characteristics of menstrual cycle. The main problem is the
determination of period in which the measuring would be carried out, so that the results could be
directly linked to a certain hormone or phase of the menstrual cycle. Generally it could be said
that menstrual cycle does not influence muscle contractility and maximum oxygen consumption,
lactate level, heart rate, breathing volume, hemoglobin levels. Therefore, women who compete in
anaerobic and aerobic sports do not have to adjust competition schedules to their menstrual cycle.
On the other hand the increase of body temperature in the luteal phase of the menstrual cycle,
possible cardiovascular strain in this phase, influence of progesterone on the respiratory center,
the rise of breathing frequency and volume can have negative influence on long-term intensive
sport activities. For this sort of activity female athletes are recommended to adjust their
competition schedule to menstrual cycle.
Keywords: menstrual cycle, hormone, exercise, sport, result
Methodological problems in analyzing menstrual cycle
Four important periods can be identified within menstrual cycle. Their alternation is conditioned
by the changes in level of four hormones and they are followed by certain, more or less marked,
physiological changes in a woman’s organism.
In a simpler way the whole cycle can be divided in two parts:
1. Follicle stage (from the first day of menstrual bleeding to ovulation- 14. day of cycle).
Its name comes from processes in ovary, where in this period follicular with egg is being
produced.
* Corresponding author: Medical Faculty, Department of Physiology, Hajduk Veljkova 3, 21000 Novi Sad, Serbia,
karanvedrana@gmail.com, +381658893019
© 2013 Faculty of Sport and Physical Education, University of Novi Sad, Serbia
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M. P. Mladenović
2. Luteal phase (from ovulation to the first day of menstrual bleeding of next cycle; in
cycle lasting for 28 days this phase covers long period of 14 days). The name also comes from
processes in ovary, where after ovulation, that is, after dropping the egg from follicular, a yellow
body is created- corpus luteum. Because of the processes in uterus this stage is sometimes called
secretory phase; in that case, what is called follicular phase can be divided in menstruation-first 4
or 5 days of the cycle and proliferative stage. So, there are four important periods in menstrual
cycle: menstrual bleeding, follicular phase, ovulation and luteal phase.
For the need of analyzing menstrual cycle, sometimes it is necessary to divide each of two
main stages into three parts: early, middle and late.
Cyclic alternation of these phases is under the control of two hormones of pituitary:
Follicular stimulating hormone - FSH and luteinizing hormone - LH, which reacts directly but
also through the control of releasing the other two hormones. Those are: Estrogen, which reaches
the maximum of secretion at the moment of ovulation, along with the maximum secretion of FSH
and LH, and the other peak, which is of less intensity, is reached in the middle of luteal phase.
Progesterone, whose maximum secretion is also expected by the middle of the luteal phase of
menstrual cycle.
The most obvious physiological change within menstrual cycle is increase in body
temperature in luteal phase. Cyclic alternation of phases of menstrual cycle can also be followed
by other physiological changes such as heart rate, change of the cognitive function, breathing
frequencies, tolerance and subjective perception of effort, muscle contractility… However, apart
from the change in body temperature, which is easy to register and prove, finished analysis of the
other physical changes did not give consistent results, in the first place because of methodological
problems of menstrual cycle analysis. How to recognize days of menstrual cycle in which the
“measurements” will be carried out so that results could be undoubtedly linked to a certain phase
or a certain hormone?
Earlier analysis of menstrual cycle were based on counting days of the cycle, starting
from the first day of menstrual bleeding, considering only women with regular menstrual cycle
and relying only on the fact that ovulation comes at the end of follicular phase, that is in the
middle of cycle or approximately on 14th day. Main disadvantage of this method is found in big
variations in duration of folicular phase even with the women with regular cycle. Contrary to
lutheal phase which is a lot more even in the duration (Cole, Ladner & Bryn, 2008; Harlow &
Ephross, 1995). Therefore, ovulation can be detected more precisely by counting beck words,
starting from the first day of the next cycle. A solution for creating an experiment would be
measuring on days determined by counting forward from the first day of menstruation (e.g. from
11. to 14. days when the peak of estrogen is expected and between 19. and 22. days when the
peak of progesterone is expected). The control for each measuring would be counting beck words
from the first day of the next cycle. So, in the case of major mismatching the found result
wouldn’t be used in final analyses. There is another setback in this method. Even among the
woman with regular menstrual cycle there is a great percentage of them with so colled
anovulatory cycle (cycle in which ther is no ovulation) or LPD - luteal phase deficient cycles;
both are characterized by low level of progesterone in the second part of the menstrual cycle. It is
a mistake to deal with the assumption that testing was performed in the middle of the luteal
phase, in the period of maximal concentration of progesterone and connect the received results
with progesterone effects, while there was anovulatory or LPD cycle. If we speak about analyzing
menstrual cycle in sports women, it should be stated that there are lot of LPD cycles (42%) and
anovulatory cycles (12%) in woman who practice recreational running (De Souza, et al., 1998).
The other, relatively simple method used for detection of cycles phase, is measuring body
temperature, basal body temperature - BBT. Generally from the moment of ovulation BBT
increases on the average by 0,3 °C and this slightly increased temperature maintains through
whole luteal phase of the cycle. This method has its disadvantages. Firstly, it is confirmed that
some women do not have already mentioned increase in BBT after ovulation (Marshall, 1963).
12
Menstrual cycle and maximal sport result
Further more, even thou the increase of BBT in luteal phase is connected to increase of
progesterone in that phase, so far analyses haven’t determined an important connection between
progesterone and increase in BBT (Marshall, 1963; Horvath & Drinkwater, 1982; Bauman,
1981); so results received in this way should not be taken with confident. Detecting LH -
luteinizing hormone in urine. When in this way peak of LH is detected, ovulation can be expected
in next 14 to 26 hours, with 95% of certainty (Miler & Soules, 1996).
Measuring estrogen and progesterone in saliva or detection of theirs metabolites in urine
are reliable, thou a bit les sensitive methods, comparing to contemporary golden standard in
determination of menstrual cycles phase - identifying serum concentration of estrogen and
progesterone. Determination of both hormone concentration is unique way to confidently
determine three important periods in menstrual cycle (according to the level of hormones):
1. Early follicular phase with low levels of both hormones;
2. Late follicular phase, peak of estrogen and low level of progesterone;
3. Middle luteal phase with high concentration of both hormones.
Even if a big “disadvantage” of this method is left out - need for multiple blood taking,
another problem arises. Not in the method itself, considering it gives precise hormone values at
the moment of blood taking, but in so cold pulsatile secretion of sex hormones. Because of this
there are marked variations in their concentration even within several hours (Filcori, Butler,
Crowley, 1984). In the first place, during the whole luteal stage concentration of progesterone
varies. This is why concentration determined from blood sample dos not have to match the
highest daily concentration or the concentration at the moment of experimental work. The
problem can be partially solved by taking blood early in the morning when concentration of
hormone is the highest (Syroup & Hammond, 1987). Additional problem in analyzing menstrual
cycle with sports women is brought by the fact that physical activity increases hormone
concentration, so blood taking is recommended in the period of resting (Keiser & Rogol, 1990;
Jurkowski, et al., 1978). Results can be influenced by reaction of estrogen and progesterone.
Estrogen during menstrual cycle reaches high values twice: once in late proliferative phase with
the low level of progesterone, and second time in middle luteal phase with high level of
progesterone. That is why two women can have same levels of estrogen but physiological effects
are different because of different progesterone level. Therefore some studies suggest that apart
from detecting absolute concentration of estrogen and progesterone, their relation should also be
determined (Bunt, 1990).
There is another, les mentioned way of determining ovulation. Mini microscope or Maybe
Baby. During proliferative phase with increase of estrogen level, concentration of salt in saliva
rises. Observed through microscope salt in dried saliva forms different structures in the period of
ovulation and immediately before it (peak of estrogen) than in different parts of cycle. Some
studies show that sensitivity of this method in detecting “fertile days” - period of ovulation, is
over 90% (Galati, 1994). If for some reason (high price, invasiveness, pulsatile secretion of
hormones), we wont to avoid detecting serum concentration of estrogen and progesterone or LH
level in urine (it is necessary to collect urine for 24h), for the need of menstrual cycle research,
phases could be approximately determined by counting days from first day of the cycles. To
lower the number of possible mistakes as much as possible, this simple method can be combined
with one of more alter non-invasive methods which will serve as control
(counting days
backwards from the first day of the next cycles, taking body temperature every day and even
using mini-microscope).
13
M. P. Mladenović
Time of testing
If question of recognizing cycle phase is solved in satisfactory way, what follows is a
choice of periods (days) in menstrual cycle in which experiment research will be carried out.
Observing relations between estrogen and progesterone, three phases are determined (table 1):
1. Early follicular phase (from 1. to 6. day) - low level of both hormones;
2. Late follicular
(from 9. to
13. day)
- high level of estrogen and low level of
progesterone;
3. Middle luteal phase (from 18. to 24. day) - when the level of both hormones is high.
It is related to cycle lasting for 28 days.
Menstrual cycle and sports performance
When the method for determining menstrual cycle is chosen and when the periods for
experimental research are chosen, an experiment can be created. In this experiment influence of
menstrual cycle to numerous physiological parameters is analyzed. It is expected for this
parameters to vary in its quality and quantity following increase and decrease in level of female
sex hormones. Topic of this article is influence of menstrual cycle to sports performance. Firstly,
parameters which can be measured will be reviewed. After that, finished thesis will be
approximately divided in, so to say positive ones (those in which the connection between sport
performance and certain periods in menstrual cycle is confirmed) and negative ones (those which
deny such connection).
So far, the most often parameters that were measured in researches are: muscle
contractility and maximum oxygen consumption VO2 max. Testing muscle contractility includes
measuring muscle strength after voluntary contraction or after electro stimulation, monitoring
muscle relaxation and muscle fatigability. Maximum oxygen consumption represents ability of
organism to transport and use oxygen. It represents physical readiness of a person. It could be
measured directly when with gradual increase of effort an ergo-bike or treadmill, ventilation, as
well as O2 and CO2 in breathed and exhaled air, are measured readiness of a person. It could be
measured directly when with gradual increase of effort ergo-bike or treadmill, ventilation, as well
as O2 and CO2 in breathed and exhaled air, are measured. VO2 max is reached when oxygen
consumption, which increased by increased effort, came to a stabile level. Apart from direct
measuring of VO2 max certain parameters which determinate maximum oxygen consumption,
can be monitored. Those are: metabolism and concentration of blood lactate, body weight, plasma
volume, hemoglobin concentration, hematocrit, breathing frequency and ventilation, heart rate,
body temperature…
Cognitive and motor functions. Although performances of both genders overlap to a
large degree, women tend to outperform men in some specific aspects of verbal ability, whereas
men achieve higher scores in spatial tasks (Hausmann 2000). Sex hormones are known to
influence the organization of the mammalian brain during critical periods of development and can
permanently alter an individual’s propensity to engage in many sexually dimorphic activity.
There is some controversy in the current literature as to the size and extent of sex differences in
cognitive abilities. Nevertheless, numerous studies have reported a sex difference in favor of
women on tests of verbal fluency, verbal articulation, perceptual speed and accuracy and fine
distal motor movements. A reliable sex difference in favor of men has been reported on task
involving spatial rotation and manipulation and mathematical reasoning (Kimura and Hampson
1994). Measuring cognitive performance of women during the menstrual cycle, it has been
reported that gonadal steroids enhance those skills for which females typically show better results
than males (Walpurger 2004). Most of the studies observed improved „female skills” during the
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Menstrual cycle and maximal sport result
luteal phase, when estrogene and progesterone are high. They found that in the midluteal phase
women performed better on tests of manual dextrity, verbal fluency and speeded articulation,
known to favor females, but more poorly on perceptual spatial tasks, known to favor males
(Kimura and Hampson 1994).
Muscle contractility. Sarwar and associates in 1996 as well as Phillips and associates
also in 1996 showed in experimental research on women with normal menstrual cycle that there
is stronger muscle contraction in the middle of cycle and in late follicular phase. Significant
decrease in muscle strength was detected in period after ovulation (Phillips, et al., 1996; Graves
et al., 1999). This points to the possible importance of estrogen to increase in strength of muscle
contraction. On the other side, Graves and associates in similar experiment found stronger muscle
contraction in the middle of luteal phase, suggesting importance of progesterone in stronger
muscle contraction (Graves et al., 1999). Finally, Dibrezzo and associates (1991) as well as
Jancee de Jonge and associates (2001) didn’t find any connection between phases of menstrual
cycle and strength of muscle contraction (DiBrezzo, Fort, Brow, 1991; Jance de Jonge, 2000).
Inconsistency of research was suggested in the beginning of this paper. What can be concluded
on this level is: in doing sports which mainly require muscle strength, sports women don’t have
to adjust their trainings and competition calendar to their menstrual cycle.
Blood lactate concentration. Certain works point to the increased concentration of blood
lactate in follicular phase. They suggest importance of estrogen in increased oxidation of fatty
acid and savings of glycogen (McCracken, M., Anisworth, B., Hackney, A.C.(1994; Jurkowski
1981). In often works, it was suggested that increase in blood lactate concentration is more likely
to be connected to a diet and availability of glycogen and fatty acids. Certain studies which
predicted strictly controlled diet before the experimental research didn’t show connection
between menstrual cycle and serum concentration of lactate (Nicklas, B.J., Hackney, A.C., Sharp,
1989; Boenen,1983). It is considered that even thou same combination of nutritional status and
menstrual cycle phase could bring to the increase of blood lactate, that wouldn’t influence VO2
max at all.
Body weight. Most of the studies didn’t show significant changes in body weight during
menstrual cycle (Leburn, et al., 1995; De Sousa, et, al., 1990). Even thou these researches deny
supposed hold of liquids in organism in certain stages of cycle, they don’t deny influence of
estrogen and progesterone to redistribution of liquids.
Redistribution of liquids within an organism would also reflect in change of plasma
volume, hemoglobin concentration and hematocrit. Unlike some earlier studies with lower
number of examinees and without hormonal verification of menstrual cycle phase, which shoved
bigger transfer of fluids outside of blood vessels and faster decrease in plasma volume in certain
cycle stages, later and more representative studies don’t register such changes (McCracken,
Anisworth, Hackney, 1994).
Heart rate. Some studies show certain increase in heart rate in middle luteal phase compared to
before ovulation cycle period (Bailez, Zacher, Mittelman, 2000). Increase of frequency could be
explained by the increase of basal body temperature in luteal phase of cycle, considering that
average rate increases 7 to 8 heartbeats for 1°C of body temperature rise. Increase in heart rate
that could happen in luteal phase with average increase of body temperature for 0,3°C would be
of no importance. That is why it is no surprising that there are much more researches in which
there is no connection found between menstrual cycle phase and change in heart rate; it goes for
the state of resting and resting after physical activity (Boenen, et al., 1983; Leburn, et al., 1995;
De souse, et al., 1990).
Basal body temperature. Basal body temperature won’t be discussed in details
considering that this fact is known for more than a century. BBT increases for 0,3°C to 0,4°C
after ovulation, and stays at that level during whole luteal cycle phase (Marshall, 1963).
15
M. P. Mladenović
Ventilation. In researches conducted on animals it has been shown that progesterone with
direct influence on hypothalamus and respiratory centre could bring to the increase of respiratory
frequency and ventilation volume. Increase in respiratory frequency and breathing volume could
be expected in luteal phase of menstrual cycle. This could be expected when both body
temperature and progesterone concentration are increased. Certain studies shoved increased
ventilation both in the state of resting and during physical exercises in luteal cycle phase
(Schoene, et al., 1981; Dempsey & Johnson, 1991). It is not necessary to mention that in certain
researches such change is not registered.
Maximum oxygen consumption. As it can be seen, certain parameters which define and
reflect VO2max, certain determinants of VO2max, vary during menstrual cycle, or at least that is
what some researches suggest. However, these changes seem not to be enough to bring to
limitation of VO2max. Most studies do not found changes in VO2max during menstrual cycle (De
Sousa, 1990; Dombovy , et al., 1987; Beidelman, et al., 1999). Considering that VO2max is the
most important indicator of sport performance in intensive anaerobic/aerobic sports, and since it
is not under the influence of menstrual cycle, at this level it can be concluded that sports women
who compete in intensive anaerobic/aerobic sports do not have to adjust their trainings and
competition to their menstrual cycle.
Conclusion
Since it has been already emphasized that in sports which, in the first place, require
muscle strength, as well as wit anaerobic/aerobic sports, maximum sport performance and results
will not depend on menstrual cycle phase. In this part instead of conclusion we can show some
more results which can be important to same sports women. Prolonged intense physical activity,
especially in conditions with high temperature and humidity of surrounding, could be restricted to
a certain level in luteal phase of menstrual cycle. Considering previous studies, showing increase
in body temperature, heart rate and ventilation in middle luteal phase of cycle (Bailez, et al.,
2000; Schoene, et al.,
1981 Williams & Krahenbuhl, 1997), which all point to increased
cardiovascular and thermoregulatory stress in this phase, during intensive and prolonged
physical activity (especially if increased thermal stress, caused by overheating or increased
humidity of surrounding is added), in this point we can conclude: If sports women play sports
which are related to prolonged and intense physical activity, they should be advised to adjust their
competition calendar to their menstrual cycle, since middle luteal phase cud have negative effect.
In the same way menstrual cycle can have influence to working efficiency, if women are
expected to work for a longer period of time in overheated and humid surrounding.
We should mention one more time research on muscle power and menstrual cycle: the best period
for top sport results (considering muscle power) would be follicular phase, as suggested by
Sarevan and associates, as well as Phillips and associates (Sarwar, et al., 1996; Philips, et al.,
1996)
Therefore, female athletes:
1. If you play sports which in particular requires muscle power, you do not have to adjust
calendar of competition and trainings to your menstrual cycle.
2. Furthermore, for sports which require muscle power, in the first place it is good to know that
some researches point to a potential positive effect of late follicular phase (from 9. to 14. day).
3. For most aerobic/anaerobic sports, you do not have adjust calendar of competitions and
trainings to menstrual cycle.
16
Menstrual cycle and maximal sport result
4. For sports which are related to long physical effort, especially if it will take place in conditions
where there is high temperature and humidity, second part of menstrual cycle should be avoided.
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Menstrual cycle and maximal sport result
Table 1 Menstrual cycle phase
Days
Estrogen
Progesterone
Follicular
Early
1-6
low
low
phase
follicular
phase
Middle
6-9
increase
low
follicular
phase
Late
9-13
high (around ovulation)
low
follicular
phase
Ovulation
14.day
low
low
Luteal
Early
15-18
increase
increase
Phase
luteal
phase
Middle
18-24
high
high
luteal
phase
Late
24-28
decrease
decrease
luteal
phase
19