Entries in Women (2)

Tuesday
Jul262011

Endurance Performers and Iron-Deficiency

By: Karoly Piko.
Chief Physician at the Department of Emergency Medicine
Site Link: Coachr.

Karoly, Piko M.D.: Chief Physician at the Department of Emergency Medicine, Joso Andros County Hospital, President of the Hungarian Association of Emergency Medicine since 1995, Head Physician of the Hungarian National Olympic and Track and Field teams since 1980. Votfous publications in the fields of emergency medicine and sport injuries.

Endurance performers are susceptible to iron-deficiency because the absorption of iron cannot balance the losses incurred through training. Therefore, a preventive daily dose of 105 mg of ferrous sulphate is necessary, especially for young women. The symptoms of iron-deficiency often remain undiscovered. The haematological parameters of training iron-deficient and anaemic women improve when a daily 210mg ferrous sulphate dose is applied. In endurance performers the effects of iron-deficiency on the synthesis of neurotransmitters, cognitive function, mitochondrial function and protein metabolism remain topics for future research studies.

A large number of sports medicine studies have looked at iron-deficiency anemia in athletes. Many of them have proved the role of iron in blood synthesis, in the activation of enzymes necessary for synthesis, the catabolism and function of neurotransmitters (dopamine, serotonin and noradrenalin); and in the regeneration of cells. Table 1 summarizes the symptoms of iron-deficiency and it is important to emphasize that the symptoms are not due to anemia.

Some of the literature argues that performers---especially endurance athletes---are mildly iron-deficient, which places limits on their performance potential. In other research the contrary finding was put forward so the role of iron substitution and preventive iron therapy is often contested.

The author has examined iron-deficient, iron-deficient anaemic and non-iron deficient endurance athletes and also reviewed the recent related literature and compared it with other findings. 

Methods 

Endurance performers from athletics and triathlon were examined. In the morning pre-prandial blood sample haematological parameters were examined (ferritin, haemoglobin, transferrin, red blood cell volume and iron levels). The participants were divided into three groups:

a. The first group consisted of male and female athletes, who received no iron preparations.

b. In the second group participants received 105mg of ferrous sulphate daily.

c. In the third group known iron-deficient, anaemic female athletes were studied.

In each group the mathematical average of every parameter was determined. After twelve weeks of training the laboratory studies were repeated.

Results

Figure 1 summarizes the development of laboratory parameters in fifteen male athletes (mean age 18 years), who did not receive iron therapy. In these cases anaemic did not develop, in two cases latently deficient iron levels were noticed. In this group the author observed a tendency towards low iron levels.

 

Figure 2 shows the parameters of fifteen female athletes (mean age 20.2 years), who did not receive iron therapy. In six cases iron-deficiency and, in two cases, iron-deficiency anaemic was observed.

 

Figure 3 shows the parameters of 20 male competitors (mean age 21.2 years), who received 105mg ferrous sulphate daily during the period of training. After three months neither iron-deficiency, nor iron- deficiency anaemia developed.

Figure 4 shows the parameters of long distance running and triathlon female athletes who received 105mg daily doses of iron sulphate.

Figure 5 reviews the haematological parameters of 8 female competitors (mean age 20.5 years), known to have iron-deficiency anaemia, who received 210mg ferrous sulphate daily. Our results show that, in spite of training, the propensity for iron-deficiency and anaemia decreased.

Discussion

For decades many studies have looked at the role of iron-deficiency and its effects on performance. Iron absorption and loss should reflect a dynamic equilibrium (Fig. 6.). In the case of sports performers loss of iron is increased by many factors such as perspiration, gastrointestinal and urogenital bleeding during training, and inefficient iron intake. The so-called "runner anaemia" is the result of the increased fragility of the red blood cells, according to some experts. Other studies question that theory by illustrating the similar haematological levels found in swimmers. 

The factors above are especially important in endurance athletes. It is evident that, in the case of iron-deficiency, the organism tries to compensate by increasing the absorption of iron. It is not clear however, whether the organism can maintain the new equilibrium.

The symptoms of iron-deficiency should be separated from those of anaemia. Because they appear long before anaemia is evident and so remain unrecognized. (see Table I.); the symptoms of the patient are often regarded as a result of increased training.

In spite of the fact that there is controversy over the relationship between iron-deficiency and diminished performance (in mild iron-deficiency no deterioration in performance was noticed), it is difficult to imagine that low iron induced neurotransmitter dysfunction would not negatively influence CNS function or even dysfunction of myogen cell metabolism, both leading to a reduced ability to perform.
It seems that in the case of endurance sports preventive iron supplementation is necessary, because our organism cannot cope with the increased loss of iron. There is no need to fear an overdose of iron, because only the required amount of Iron is absorbed, the rest is eliminated in faeces.

Conclusion

  1. The studies of iron metabolism in endurance athletes reveal the following:
  2. In endurance athletes iron-deficiency is common and anaemia is often observed.
  3. The haemostatus of these athletes should be monitored at least every three months.
  4. A preventive daily intake of 10Smg ferrous sulphate seems to be necessary; over dosage was not observed.
  5. A therapeutic dosage (210mg/day) improved the haemostatic parameters in spite of training. There was no need for intravenous application.

The effect of iron on cognitive functions, neurotransmitter synthesis, protein metabolism and the metabolism within the mitochondria needs future evaluation.

Bibliography

ASHENDEN MJ, DOBSON GP, HAHN AG
Sensitivity of reticulocyte indices to iron therapy in an intensely training athlete. In: Br J Sports Med ( ENG-LAND) Sep. 199832 (3) p259-6o ISSN: 0306- 3674

ASHENDEN MJ; MARTIN DT; DOBSON GP; MACKINTOSH C; HAHN AG
Serum ferritin and anaemia in trained female ath- letes. In: Int J Sport Nutr (UNITED STATES) Sep 1998 8 (3) p223-9ISSN: 1050-1606

BERMEJO B; OLONA M; SERRA M; CARRERA A; VAQUEJ
Prevalencia de ferropenia en la poblacion laboral femenina en edad fertil. In: Rev Clin Esp (SPAIN) Jul1996 196 (7) p446-50 ISSN: 0014-2565

BURKE L
Practical issues in nutrition for athletes. In: J Sports Sci (ENGLAND) Summer 1995 13 Spec No pS83-90 ISSN: 0264-0414

CLARKSON PM
Micronutrients and exercise: anti-oxidants and minerals. In: J Sports Sci (ENGLAND) Summer 199513 Spec No pS11-24 ISSN: 0264-0414

ESCANERO J F; VILLANUEVA J;RoJO A; HERRERA A; DEL DIEGO C; GUERRA M
Iron stores in professional athletes throughout the sports season. In: Physiol Behav (UNITED STATES) Oct 1997 62 (4) p 811-4 ISSN:0031-9384

GARZA D; SHRIER I; KOHL HW 3RD; FORD P; BROWN M; MATHESON GO
The clinical value of serum ferritin tests in endurance athletes. In: Clin J Sport Med (UNITED STATES) Jan 1997 7 (1) p46-53 ISSN: 1050-642X

GASTMANN U; PETERSEN KG; BOCKER J; LEHMANN M
Monitoring intensive endurance training at moderate energetic demands using resting laboratory markers failed to recognise an early overtraining stage. J Sports Med Phys Fitness ( ITALY) Sep. 1998 38 (3) p 188-93ISSN:0022-4707

KHALED S; BRUN JF; WAGNER A; MERCIER J, BRINGER J; PREFAUT C;
Increased blood viscosity in iron-depleted elite athletes. In: Clin Hemorheol Microcirc (NETHERLANDS) Jul1998 18 (4) p 309 -18 ISSN: 1386-0291

NIELSEN P; NACHTIGALL D
Iron supplementation in athletes. Current recommendations. Sports Med (NEW ZEALAND) Oct 199826 ( 4) p207-16 ISSN: 0112-1642

NUVIALA RJ; CASTILLO MC; lAPIEZA MG; ESCANERO JF
Iron nutritional status in female karatekas, hand- ball and basketball players, and runners. In: Physiol Behav (UNITED STATES) Mar 199659 (3) p449-53 ISSN:0031-9384

SAKURADA K;TANAKAJ
{Sport-anaemia: studies on haematological status in high school boy athletes}. In: RINSHO BYORI (JAPAN) JUL 199644 (7) p616-21ISSN: 0047-1860

Tuesday
Jul262011

Strength Training for Women: Hormonal Considerations

By: C. Harmon Brown, M.D.
Chair of USATF's Sports Medicine and Sciences Committee.
From: Published in Track Coach: No137
Site Link: Coachr.

 

Dr. Brown, Chair of USATF's Sports Medicine and Sciences Committee, referred to this in a note to us as a "think piece." He calls for coaches and scientists to continue this kind of study. This is a well-documented article, which may lead the interested coach to investigate further. We welcome response to this important article.

Strength training to enhance sports performance and improve fitness is now a common means of exercise for women. It has progressed to the point that there is now a world championships in weightlifting for women.

For many years resistive exercises for women were shunned for fear of these athletes becoming "masculinized" through the use of heavy weights. However, early studies showed that women were able to exhibit considerable improvements in strength with only minimal degrees of muscle hypertrophy (2). These researchers pointed out that the likelihood of major muscle hypertrophy from resistance training was small in comparison to males, as women have blood levels of the anabolic hormone testosterone which are only 5-10 per cent of those of men.

Many subsequent studies have borne out these early findings. Further, resistance training itself does not appear to increase basal levels of testosterone in women, and strength gains are not correlated with blood testosterone levels (3-5).

The endocrine aspects of exercise science have increased greatly in recent years, especially in the areas associated with resistance training. Assessing the roles of the various hormones as to the cause-and- effect relationships in response to any exercise stimulus can be very complex.
Hormonal levels in blood and tissues are influenced by their production from the parent organ, clearance from the blood by the liver, kidneys, and other peripheral tissues, and their binding to specific receptor sites in target organs.

In addition, steroidal hormones such as androgens, adrenal hormones, and ovarian hormones circulate in the blood bound to specific carrier proteins, with only a tiny fraction in the "free" form which is available to tissues.

Evaluation of the numerous studies which have been carried out concerning the responses of the endocrine system are further complicated by the variety of test protocols which have been utilized. Aerobic vs. resistance loading produces different hormonal responses, and even seemingly similar studies may yield different results. The athlete's state of training and nutrition can also influence the metabolic and hormonal outcomes.

There are at least three anabolic hormones which are responsible for muscle hypertrophy: testosterone (and dihydrotestosterone), pituitary growth hormone (GH), and insulin-like growth factor I (IGF-I), formerly called somatomedin-C.

TESTOSTERONE

Initially, studies focused on the role of testosterone in response to an exercise stimulus, especially resistive loading. It soon became apparent that, in addition to different basal levels between men and women, the response to exercise is quite different. Following a bout of resistive exercise, the male's testosterone level rises considerably, while in women the values change little, if at all.
Further, the disposition of testosterone in the body differs between the sexes. In males, about 50 per cent of the testosterone is bound to receptors in muscle, while only about 10 percent is cleared in this manner in women. However, women do show a greater response of the weaker adrenal androgen, androstenedione.

Concerns that resistive training in women raises basal testosterone levels, or that higher basal testosterone levels are accompanied by greater strength gains, have not been borne out.

GROWTH HORMONE

Growth hormone responds to both aerobic and resistive exercise. Growth hormone stimulates muscle growth by facilitating the transport of amino acids across cell membranes, activating DNA transcription in the muscle cell nucleus, thus increasing the amounts of RNA and protein synthesis.

INSULIN-LIKE GROWTH FACTOR

Insulin-like growth factor I (IGF- I) is a potent anabolic factor. It is believed that growth hormone's effects are mediated through IGF-I. IGF-I is stored in the liver and peripheral tissues. It is released slowly (16-28 hours) after growth hormone stimulation. In those situations in which it was measured, IGF-I levels have risen little or not at all after exercise bouts which have been sufficient to elevate growth hormone concentrations. Further, increases in IGF-I did not seem to correlate with the rises in GH. The reasons for this are not clear.

It would appear from the foregoing that the growth hormone IGF-I complex plays a significant role in the development of muscle hypertrophy and strength in women. Hence, strength programs for women should focus on maximizing growth hormone production.

ELEVATING GH LEVELS

In a series of elegant studies, W. Kraemer, et al. (9-12) examined the hormonal responses to a wide variety of resistive training protocols in both men and women. By varying the resistive load (5-RM vs. l0-RM) and the rest interval (1 minute vs. 3 minutes), they were able to demonstrate considerable differences in the response of several hormones.

In summary, the greatest rises in GH occurred with the protocol in which eight different exercises were used, with three sets of each exercise. The resistance was l0-RM, or approximately 70-75 percent of the l-RM, and the rest interval was one minute between each exercise and between each set.

THE EFFECT OF THE MENSTRUAL CYCLE

Similar responses were seen in both men and women, with the women having somewhat higher baseline GH levels, and slightly greater exercise responses. However, in all prior studies by these and other authors, women were studied only during the follicular phase (first half) of the menstrual cycle.
Only recently has the effect of the menstrual cycle on various hormonal responses to resistive training been assessed (6). RR Kraemer, et al. (7, 8) studied the changes in hormonal response which occurred during both the follicular and luteal phases of the cycle in the same group of subjects. These women were subjected to a moderate exercise regimen of three sets of 10 repetitions of four different exercises with a 2- minute rest interval. There was a significantly higher GH response during the luteal phase, as well as much higher estradiol levels. Other studies have suggested that the female hormone estradiol facilitates the release of growth hormone.

TAILORING PROGRAMS TO THE MENSTRUAL CYCLE

These studies suggest that strength training programs for women should be tailored to each athlete's menstrual cycle. Although there have been no studies to validate the effect of these cyclic hormonal variations on muscle growth and strength development, the research findings are strongly suggestive that such a study would be of considerable value.

Until such a study is done, however, imaginative strength coaches should consider devising strength development programs which take into account these hormonal fluctuations which occur during the menstrual cycle. Such considerations might be especially valuable during the basic "hypertrophy" mesocycle of a strength development program.

These programs should consider:

  1. During the luteal phase (second half) of the menstrual cycle strength training should consist of "moderate intensity" loading, using 3-4 sets of 8-10 repetitions at 65- 75% of the 1- RM, done three times a week. These exercises should involve the large muscle groups of the upper and lower extremities and trunk, i.e., bench press, squats, power cleans, leg press, sit-ups, dead lifts, etc.
  2. The rest interval between sets and exercises should be no more than two minutes, and preferably shorter.
  3. A similar routine also may be of value during the follicular phase (first half) of the cycle, although the estradiol and GH responses may be lower.
  4. f the athlete is using oral contraceptives, no phasic change in GH response can be expected (1) unless the oral contraceptive is of the "tri-phasic" variety. Several studies of athletes using oral contraceptives have been done. These have yielded conflicting results as to whether there is a greater-than-expected GH response, probably because of variations in hormonal strength and type, and in exercise protocol.
  5. During the "strength" phase of the training cycle (lower repetitions, higher loading), i.e., four sets of five repetitions at 80% of l-RM, a lesser response of estradiol and GH is to be expected, and the training program need not be adapted to the menstrual cycle.

It is hoped that this paper will stir some thought and even controversy in the strength-training community and will lead to further studies and some empirical trials by innovative coaches and scientists.