Physical activity, nutrition, and reproduction

Dietary restriction and/or exercise training impairs spermatogenesis in normal rats

Dietary restriction and/or exercise has been shown to have multiple benefits for health. However, its effects on reproductive health and the mechanisms by which it regulates reproductive function remain unclear. Here, to evaluate its effects on spermatogenesis and sperm function, rats were divided into 4 groups: ad libitum-fed sedentary control, dietary restriction (DR), exercise training (ET), and dietary restriction plus exercise training (DR+ET) groups. Results indicated that body weight, epididymal fat pad weight, and sperm counts were significantly reduced in the DR, ET, and DR+ET groups. Moreover, sperm motility and capacitation-associated protein tyrosine phosphorylation were suppressed in the DR and DR+ET groups, but not the ET group. Microarray analysis revealed that the number of downregulated genes was higher than that of upregulated genes in the DR and/or ET groups. About half of the downregulated genes are common after exercise training and/or diet restriction. Gene ontology analysis showed that downregulated genes in the DR, ET, and DR+ET groups affected spermatogenesis through overlapping pathways, including glucocorticoid, corticosteroid, extracellular structure organization, and estradiol responses. Our findings suggest that diet restriction and/or exercise training may present potential risks to male reproductive dysfunction by disrupting normal gene expression patterns in the testis. Novelty: Dietary restriction and/or exercise can lead to the damage of spermatogenesis as well as sperm maturation. Sperm functional changes are more sensitive to dietary restriction than exercise training. Dietary restriction and exercise impair spermatogenesis through overlapping biological pathways in the testis.

Evidence of profound ovarian suppression on combined hormonal contraception resulting in dramatically different ovarian reserve testing and oocyte retrieval outcomes: case report and review of the literature

Objective

To describe a case report and demonstrate that degree of ovarian suppression with continuous combined hormonal contraception (CHC) may be more profound than previously described and may present similarly as decreased ovarian reserve.

Design

Case report and review of the literature.

Setting

Private practice in vitro fertilization center.

Patient(s)

A 36-year-old single gravida 0 presenting for oocyte cryopreservation on CHC.

Intervention(s)

Discontinuation of vaginal ring combined hormonal contraceptive for 6 months.

Main Outcome Measure(s)

Antral follicle count, antimüllerian hormone, day 3 follicle-stimulating hormone, total oocytes, and mature oocytes retrieved before and after discontinuation of CHC.

Result(s)

After a 6-month break from CHC, our patient’s antimüllerian hormone level increased from undetectable levels to 3.45 ng/mL, day 3 follicle-stimulating hormone level decreased from 14.9 IU/mL–6.17 IU/mL, and antral follicle count improved from 0–28. In addition, the number of oocytes retrieved after a 4-month CHC break and 6-month break increased from 8 to 29, respectively.

Conclusion(s)

In patients on long-term combined continuous hormonal contraception, profound ovarian suppression can result in a clinical picture of diminished ovarian reserve and extremely poor response to high-dose stimulation, which may be reversed by more time off from suppression.

A Systematic Literature Review of Factors Affecting the Timing of Menarche: The Potential for Climate Change to Impact Women's Health

Menarche is the first occurrence of a woman’s menstruation, an event that symbolizes reproductive capacity and the transition from childhood into womanhood. The global average age for menarche is 12 years and this has been declining in recent years. Many factors that affect the timing menarche in girls could be affected by climate change. A systematic literature review was performed regarding the timing of menarche and four publication databases were interrogated: EMBASE, SCOPUS, PubMed, and Cochrane Reviews. Themes were identified from 112 articles and related to environmental causes of perturbations in menarche (either early or late), disease causes and consequences of perturbations, and social causes and consequences. Research from climatology was incorporated to describe how climate change events, including increased hurricanes, avalanches/mudslides/landslides, and extreme weather events could alter the age of menarche by disrupting food availability or via increased toxin/pollutant release. Overall, our review revealed that these perturbations in the timing of menarche are likely to increase the disease burden for women in four key areas: mental health, fertility-related conditions, cardiovascular disease, and bone health. In summary, the climate does have the potential to impact women’s health through perturbation in the timing of menarche and this, in turn, will affect women’s risk of disease in future.

Impact of exercise on oocyte quality in the POLG mitochondrial DNA mutator mouse

The mtDNA 'mutator' mouse, also called the 'POLG' mouse, is a well-characterized model frequently used for studies of progeroid aging. Harboring a mutation in the proofreading domain of the mitochondrial polymerase, polymerase-γ (Polg), POLG mice acquire mtDNA mutations at an accelerated rate. This results in premature mitochondrial dysfunction and a systemic aging phenotype. Previous work has demonstrated that the progeroid phenotype in POLG is attenuated following endurance exercise, the only reported intervention to extend health span and lifespan of these mice. Herein, oocyte quality was evaluated in sedentary and exercised POLG mice. In mice homozygous for the Polg mutation, litter size is dramatically reduced as compared to heterozygous Polg mice. Following ovarian hyper-stimulation, oocytes were retrieved until 9 months of age in exercised and sedentary groups, with no oocytes ovulated thereafter. Although ovulated oocyte numbers were not impacted by exercise, we did find a modest improvement in both the ovarian follicle reserve and in oocyte quality based on meiotic spindle assembly, chromosomal segregation and mitochondrial distribution at 7 months of age in exercised POLG mice as compared to sedentary counterparts. Of note, analysis of mtDNA mutational load revealed no differences between exercised and sedentary groups. Collectively, these data indicate that exercise differentially influences somatic tissues of the POLG mouse as compared to oocytes, highlighting important mechanistic differences between mitochondrial regulatory mechanisms in the soma and the germline.

How maya women respond to changing technology : The effect of helping behavior on initiating reproduction

In the mid 1970s labor-saving technology was introduced into a Maya subsistence agricultural community that markedly increased the efficiency with which maize could be ground and water collected. This increased efficiency introduces a possible savings in the time that women allocate to work, which can be reapportioned to child care, food production, domestic work, or leisure. An earlier study suggested that this labor-saving technology had a positive effect in decreasing the age at which these Maya women begin their reproductive careers. Although there is a statistical association between the age at which women bear their first child and the introduction of modern technology, this association does not demonstrate that the decline in age at first birth is causally related to the presence of technology. This paper pursues two objectives to evaluate this potential causal relationship in greater detail. First, a theory relating technological change to the initiation of a reproductive career is briefly developed in order to make qualitative predictions about behavioral changes as a response to changing technology. Second, these predictions are then tested against time allocation data recently collected in this same Maya community.We suggest that both of the conditions necessary to initiate reproduction-fecundity and access to mates-fundamentally depend on the amount of help that a girl provides to her family. Further, the help that a girl provides can be affected by technological changes. Analyses show that when modern technology is available, unmarried young women do not change the time allocated to domestic tasks and child care, and allocate more time to low-energy leisure activities. This lack of perceived benefit to working more and a potential concomitant shift towards a positive energy balance may in part explain why Maya women leave home and initiate reproduction at a younger age after labor-saving technology is introduced.

Nutrition regulation of male accessory gland growth and maturation in Tribolium castaneum

Insulin/IGF-1 signaling (IIS) pathway is known to control growth, development and reproduction. Insulin-like peptide mediated body size plasticity in Drosophila melanogaster has been reported. Here, our studies showed that IIS pathway and nutrition regulate growth and maturation of the male accessory gland (MAG) in the red flour beetle, Tribolium castaneum. The size of MAG increased from day 1 to day 5 post-adult emergence (PAE). This increase in the size of MAG is contributed by an increase in cell size, but not cell number. The growth of MAG was impaired after double-stranded RNA (dsRNA)-mediated knockdown in the expression of genes coding for ILP3, InR, Chico, PI3k, AKT, and GATA1 involved in IIS pathway. Interestingly, starvation showed similar effects on the growth and maturation of MAG. The phenotypes observed in animals where IIS signaling pathway genes were knocked down are similar to the phenotypes observed after starving beetles for 5 days PAE. These data suggest that nutrition signals working through IIS pathway regulate maturation of MAG by promoting the growth of MAG cells.

Menstrual effects among women exposed to polychlorinated biphenyls and dibenzofurans

BACKGROUND

Polychlorinated biphenyls (PCBs), dibenzofurans (PCDFs), and dibenzo-dioxins (PCDDs) may affect the female reproductive system in humans. A mass poisoning occurred in Taiwan due to PCBs/PCDFs-contaminated cooking oil, and was called the Yucheng (oil-disease in Chinese). We aimed to determine whether Yucheng women were affected in their menstruation.

METHODS

After the event, we followed the exposed individuals and an age-matched neighborhood reference group. Menstrual cycle characteristics and age at menarche were obtained by a telephone interview. We used multiple linear and logistic regression to examine the association between PCBs/PCDFs and menstrual cycle characteristics, after adjusting for confounding factors.

RESULTS

Totally 445 women responded satisfactorily and were included in the analyses of menstrual characteristics. Menstrual cycle irregularity and dysmenorrheal did not differ between Yucheng and referents. Yucheng women's menstrual cycles were 0.5 (95% CI: 0.0-0.5; p=0.03) days shorter than those of the referents. The Yucheng women with skin lesions caused by PCBs/PCDFs were more prominently affected, with the cycles 1.2 days shorter than the referents. Yucheng women exposed to PCBs/PCDFs at the premenacheal period had reduced cycle length (-0.7 day, 95% CI: -1.4 to 0.0; p=0.04) and longer days of menstrual flow (0.5 day, 95% CI: 0.0-1.0; p=0.04). Among those women who were exposed at an age of 5-9 years, menarche started slightly earlier with borderline significance.

CONCLUSIONS

Shorter menstrual cycle length and a longer duration of bleeding in each cycle were found among women previously exposed to PCBs/PCDFs. These effects were more obviously observed among those exposed at premenarcheal ages.

Teen motherhood in cross-cultural perspective

Teen motherhood is the prevalent childbearing pattern in most traditional populations. Yet early motherhood is associated with negative biological and social outcomes in the developed world. We review the teen pregnancy literature in light of this discrepancy, emphasizing two core debates. The first debate centers on whether teens have poor pregnancy outcomes compared to older women, and whether negative outcomes are biologically based. Second, we consider the debate over the confounding effects of socio-economic conditions associated with being young. When teens are considered as a group, results are inconsistent across studies. When teens are disaggregated by age, the strongest finding across studies is that biological risk is concentrated in only the youngest of mothers. Negative consequences are associated with teen motherhood not because of chronological age per se, but because of relative developmental maturity and the availability of non-maternal support. In most traditional societies as well as in some sectors of developed societies, teen motherhood occurs within the context of extended kin networks and is subsidized through reliable economic and childcare assistance. Child-rearing practices, rather than pregnancy per se, may explain much of the discrepancy in the prevalence, success and attitudes toward teen motherhood in traditional and developed societies.

Oxidative stress and antioxidants: exposure and impact on female fertility

BACKGROUND

Reproductive failure is a significant public health concern. Although relatively little is known about factors affecting fertility and early pregnancy loss, a growing body of literature suggests that environmental and lifestyle factors play an important role. There is sufficient evidence to hypothesize that diet, particularly its constituent antioxidants, and oxidative stress (OS) may influence the timing and maintenance of a viable pregnancy. We hypothesize that conditions leading to OS in the female affect time-to-pregnancy and early pregnancy loss.

METHODS

We review the epidemiology of female infertility related to antioxidant defenses and oxidation and examine potential sources of OS from the ovarian germ cell through the stages of human pregnancy and pregnancy complications related to infertility. Articles were identified through a search of the PubMed database.

RESULTS

Female OS is a likely mediator of conception and threshold levels for OS exist, dependent on anatomic location and stage of preconception.

CONCLUSIONS

Prospective pregnancy studies with dietary assessment and collection of biological samples prior to conception with endpoints of time-to-pregnancy and early pregnancy loss are needed.

Sun exposure and age at natural menopause: A cross-sectional study in Turkish women

OBJECTIVES

In a cross-sectional study of 157 Turkish women attending outpatient clinics of a university hospital during April-May 2003, association between various subject characteristics and menopause timing was investigated.

METHODS

Characteristics were self-reported by women aged 45-60. Of the lifestyle factors, sun exposure, physical activity, food intake and dressing with headscarf were obtained as recalled average lifelong practices up to time of menopause. Cox proportional hazard modeling was used, censoring for hysterectomy, oopherectomy and HRT use.

RESULTS

Median age at natural menopause was 52 years. In multivariate analysis, earlier natural menopause was associated with low level of lifelong sun exposure (HR=6.381, 95% CI: 2.996-13.588, p< or =0.0001), heavy physical activity (HR=2.335, 95% CI: 1.305-4.177, p=0.0043), current calcium supplement use (HR=3.191, 95% CI: 1.361-7.485, p=0.0076), diagnosis of hypertension (HR=2.002, 95% CI: 1.186-3.378, p=0.0093), not owning a house (HR=3.002, 95% CI: 1.148-7.852, p=0.0250) and longer years on oral contraceptives (HR=1.085, 95% CI: 1.000-1.176, p=0.0487). Engagement in farming (HR=2.043, 95% CI: 1.056-3.952, p=0.0339), height (cm) (HR=0.953, 95% CI: 0.907-0.994, p=0.0279) and fish consumption (servings/week) (HR=0.600, 95% CI: 0.375-0.960, p=0.0331) were associated with age at menopause in univariate analysis only. For n=109 women who recalled whether maternal menopausal age was <50 or > or =50, sun exposure (HR=7.221, 95% CI: 2.971-17.547, p<0.0001) was a stronger predictor of age at natural menopause than maternal menopausal age (HR=2.882, 95% CI: 1.477-5.621, p=0.0019).

CONCLUSIONS

We identify some previously unrecognized correlates of age at natural menopause, namely self-reported lifelong sun exposure, lifelong physical activity, house-ownership, current use of calcium supplements, and lifelong fish consumption. These findings should be confirmed in larger studies.

The factors affecting the relation between the menarcheal age of mother and daughter

BACKGROUND

Menarche is one of the most important biologic signals in the life of a woman. Menarche is a biological variable which has a significant genotypic component in girls. In recent years, many studies reporting the earlier onset of menarche owing to the improvement of socio-economic conditions have been published.

DESIGN

We asked some questions about menarche to 1017 female students studying in the high schools of Manisa region in order to determine the menarcheal age and the correlation of menarcheal age between the mothers and daughters in our region.

RESULTS

The mean age at menarche for the girls was 12.82+/-1.07 years and for the mothers was 13.6+/-1.39 years. The mean menarcheal age of the mothers was higher than the mean menarcheal age of the girls (P<0.001). This difference persisted independent of the socio-economic status, nutritional state and physical activity of the girls. There was a significant correlation between the menarcheal age of the girls and their mothers (r=0.262, P<0.001). This correlation existed in all the girls with different socio-economic status, nutritional state and physical activity. However, this correlation disappeared in girls with body mass index (BMI)>25 (r=0.04, P=0.813). In girls with BMI<25, there was a correlation between the menarcheal age of the girls and mothers (r=0.282, P<0.001).

CONCLUSION

These results suggest that the menarche occurs earlier in the daughters than their mothers. The correlation between the menarcheal age of the girls and their mothers persists under all circumstances except in obesity. The mother's menarcheal age is a good predictor of the daughter's menarcheal age in non-obese girls and the BMI is an important factor.

Evolutionary health promotion

Health promotion's promise is enormous, but its potential is, as yet, unmatched by accomplishment. Life expectancy increases track more closely with economic prosperity and sanitary engineering than with strictly medical advances. Notable achievements in the past century--the decreased incidences of epidemic infections, dental caries, and stomach cancer--are owed to virologists, dentists, and (probably) refrigeration more than to physicians. Prevention speaks against tobacco abuse with a single voice, but in many other areas contradictory research findings have generated skepticism and even indifference among the general public for whom recommendations are targeted. Health promotion's shortcomings may reflect lack of an overall conceptual framework, a deficiency that might be corrected by adopting evolutionary premises: (1) The human genome was selected in past environments far different from those of the present. (2) Cultural evolution now proceeds too rapidly for genetic accommodation--resulting in dissociation between our genes and our lives. (3) This mismatch between biology and lifestyle fosters development of degenerative diseases. These principles could inform a research agenda and, ultimately, public policy: (1) Better characterize differences between ancient and modern life patterns. (2) Identify which of these affect the development of disease. (3) Integrate epidemiological, mechanistic, and genetic data with evolutionary principles to create an overarching formulation upon which to base persuasive, consistent, and effective recommendations.

Estrogen replacement therapy and female athletes: current issues

Physicians commonly recommend estrogen replacement as treatment for exercise-associated amenorrhoea. While the evidence shows that the basis of the amenorrhoea is estrogen deficiency, it is not clear that it is the only factor in the development of lowered bone density found in oligo-amenorrhoeic female athletes. Nutritional factors, significant in the development of the reproductive dysfunction, could also contribute to bone loss. No randomised, controlled studies of estrogen replacement in athletes have been published. However, one nonrandomised study of a small group of athletes does suggest that there are significant gains in bone density to be made by the initiation of estrogen therapy. More research is clearly needed.

Menstrual patterns and fecundity among non-lactating and lactating cycling women in rural highland Bolivia: implications for contraceptive choice

Choosing an appropriate contraceptive method, particularly one based on fertility awareness, depends in part upon the degree of a woman's cycling regularity. However, while the suppressive effect of lactation on ovarian function is well established, the potential influence of continued breastfeeding on menstrual patterns once post-partum cycling has resumed is largely unexamined. This longitudinal study in a population of non-contracepting Aymara women (n = 191 providing 665 non-truncated menstrual segments) identified conceptions and fetal loss via urine tests for hCG and classified segments accordingly to test the hypotheses that (1) cycles in lactating women are significantly different in length and regularity from those of non-lactating women, and (2) cycles in women living at high altitude are significantly different in length and regularity from those at lower altitudes. Analyses found that segments are significantly longer and regularity tends to be less common among lactating than non-lactating women; however, the rate of conception is twice as great among the former than the latter, and the distribution of conception outcomes does not differ between the two groups. Menstrual regularity is not the norm in this population, even among those who are not currently breastfeeding. High altitude per se does not appear to influence menstrual cycling as both regularity and segment length are comparable to other populations, hence women indigenous to high altitude are suitable candidates for a wide variety of contraceptive choices. In addition, these findings suggest that studies of fecundability limited to non-lactating women may be biased towards those of relatively lower fecundity.

Neuroendocrine regulation and actions of leptin

The discovery of the adipocyte-produced hormone leptin has greatly changed the field of obesity research and our understanding of energy homeostasis. It is now accepted that leptin is the afferent loop informing the hypothalamus about the state of fat stores, with hypothalamic efferents regulating appetite and energy expenditure. In addition, leptin has a role as a metabolic adaptator in overweight and fasting states. New and previously unsuspected neuroendocrine roles have emerged for leptin. In reproduction, leptin is implicated in fertility regulation, and it is a permissive factor for puberty. Relevant gender-based differences in leptin levels exist, with higher levels in women at birth, which persist throughout life. In adult life, there is experimental evidence that leptin is a permissive factor for the ovarian cycle, with a regulatory role exerted at the hypothalamic, pituitary, and gonadal levels, and with unexplained changes in pregnancy and postpartum. Leptin is present in human milk and may play a role in the adaptive responses of the newborn. Leptin plays a role in the neuroendocrine control of GH secretion, through a complex interaction at hypothalamic levels with GHRH and somatostatin. Leptin participates in the expression of CRH in the hypothalamus, interacts at the adrenal level with ACTH, and is regulated by glucocorticoids. Since leptin and cortisol show an inverse circadian rhythm, it has been suggested that a regulatory feedback is present. Finally, regulatory actions on TRH-TSH and PRL secretion have been found. Thus leptin reports the state of fat stores to the hypothalamus and other neuroendocrine areas, and the neuroendocrine systems adapt their function to the current status of energy homeostasis and fat stores.

EVOLUTIONARY ECOLOGY OF HUMAN REPRODUCTION

▪ Abstract  Evolutionary ecology of human reproduction is defined as the application of natural selection theory to the study of human reproductive strategies and decision-making in an ecological context. The basic Darwinian assumption is that humans—like all other organisms—are designed to maximize their inclusive fitness within the ecological constraints to which they are exposed. Life history theory, which identifies trade-off problems in reproductive investment, and evolutionary physiology and psychology, which analyzes the adaptive mechanisms regulating reproduction, are two crucial tools of evolutionary reproductive ecology. Advanced empirical insights have been obtained mainly with respect to the ecology of fecundity, fertility, child-care strategies, and differential parental investment. Much less is known about the ecology of nepotism and the postgenerative life span. The following three theoretical aspects, which are not well understood, belong to the desiderata of future improvement in evolutionary human reproductive ecology: (a) the significance of and the interactions between different levels of adaptability (genetic, ontogenetic, and contextual) for the adaptive solution of reproductive problems; (b) the dialectics of constraints and adaptive choices in reproductive decisions; and (c) the dynamics of demographic change.

Recreational and occupational physical activities and risk of breast cancer

Physical activity has been hypothesized to reduce breast cancer risk, but an inverse association has not been consistently reported. In this review, we critically evaluate for coherence, validity, and bias the epidemiologic studies on recreational or occupational physical activity, discuss the biologic plausibility of the association, and identify areas for future research. Results from seven of nine studies suggest that higher levels of occupational physical activity may be associated with a reduction in risk, at least among a subgroup of women. Eleven of 16 investigations on recreational exercise reported a 12%-60% decrease in risk among premenopausal and postmenopausal women, although a dose-response trend was not evident in most of the studies. The reduction in risk associated with exercise was more likely to be observed in case-control studies than in cohort studies. Most investigations incompletely assessed physical activity, which contributed to conflicting findings on the optimal time period, duration, frequency, or intensity of activity to minimize risk. Physical activity may exert its effects through changes in menstrual characteristics, reduced body size, or alterations in immune function. In summary, most epidemiologic studies of physical activity reported a reduction in the risk of breast cancer among physically active women. Future research studies should focus on using a cohort design to rule out recall bias as a possible explanation for the decrease in risk associated with exercise, on improving assessment of lifetime physical activity from all sources to clarify whether there is a dose-response relation or an optimal time period, duration, frequency, or intensity of activity, and on elucidating the underlying mechanisms for the inverse association.

Hormone measures in finger-prick blood spot samples: new field methods for reproductive endocrinology

Comparative endocrine studies have notably advanced understanding of ecological factors that contribute to variation in human reproductive function. Such research has relied on methodological advances that permit hormone determinations in samples that are easily and safely collected, stored, and transported, most recently on measurement of steroids in saliva. This report seeks to further expand the scope of endocrine research by demonstrating the value of blood spot samples collected by finger prick. As a sampling strategy, finger-prick blood spot collection offers the advantages of short collection time, low invasiveness, repeatability, absence of postcollection processing, low biohazard risk, and ease of sample storage and transport. We document good sample stability and present sensitive assay methods for a range of steroids and proteins (FSH, LH, PRL, T, E2, DHEAS, androstenedione, cortisol, SHGB) in blood spots that require sample volumes of 3-12 microliters and display good reliability, specificity, precision, accuracy, and convertibility of results to plasma/serum equivalent concentrations. Laboratory evaluation was augmented by a feasibility study at a remote site in Papua New Guinea that confirmed validity and stability of blood spot collections under field conditions. Research applications of blood spot sampling are illustrated with a series of studies, including cross-sectional surveys for developmental and life span endocrinology, a longitudinal, population-based developmental epidemiologic study of puberty, and serial sampling in a dynamic study of neuroendocrine response to suckling. We conclude that the sampling features and wide range of measurable biomolecules of blood spots do constitute a methodological advance for endocrine research.

Family size and age at menarche in athletes

The association between family size and age at menarche was evaluated in 370 university athletes representing seven sports, 291 white and 79 black. Age at menarche, number of children in the family (family size), and birth order were collected retrospectively by questionnaire with a follow-up interview if necessary. The effect of family size on menarche was estimated with linear regression and multiple regression. For each additional sibling in the family-age at menarche was later by 0.17 yr in white athletes, 0.21 yr in black athletes, and 0.16 yr in the total sample (about 2.0-2.5 months). The slopes for white (beta = 0.167) and black (beta = 0.208) athletes did not differ significantly. Controlling for the effects of birth order significantly increased the family size effect in white athletes (beta = 0.221), but not in black athletes (beta = 0.203) or in the total sample (beta = 0.164). The slopes for white and black athletes, after controlling for birth order, also did not significantly differ. Thus, after controlling for birth order, menarche was later by 0.16-0.22 yr (about 2.0-2.6 months) for each additional sibling in the family, which was within the range of family size effects observed in samples of nonathletes and athletes. The family size effect also persists after controlling for maternal age at menarche in a subsample of 134 athletes, thus implying an independent effect of family size. Later ages at menarche observed in athletes may thus be due in part to larger family sizes.

Retrospective longitudinal growth study of boys and girls active in sport

Longitudinal records from the Wroclaw Growth Study and the Wroclaw Longitudinal Twin Study were screened for individuals who were active in sport during childhood and adolescence and who were active in sport as young adults. The resulting sample was 25 boys and 13 girls. Heights and weights of the active boys indicated a growth pattern characteristic of early maturers, which was verified in advanced skeletal, sexual and somatic maturation during adolescence. The pubertal progress of active boys suggested no differences in tempo compared to nonathletic boys. In contrast, girls active in sport presented a pattern of growth and maturation characteristic of average maturing individuals, but were taller and heavier than local reference data. Skeletal and chronological ages of active girls did not differ, and the active girls did not differ from local reference data in sexual maturation. PHV, however, was reached later by about one-half of a year. The pubertal progress of girls active in sport did not differ from that of nonathletic girls.

Hormonal responses to graded-resistance, FES-assisted strength training in spinal cord-injured

Functional electrical stimulation (FES) assisted resistance training has been effective in increasing muscular strength and endurance in spinal cord injured men and women in preparation for FES-assisted cycle programs and for FES-assisted standing and walking. Increases in blood pressure and a concomitant bradycardia suggestive of autonomic dysreflexia have been reported during FES-assisted resistance training. Self-induced autonomic dysreflexia in athletes who use wheelchairs suppressed the normal exercise induced serum testosterone increase. We, therefore, examined the changes in hematocrit and circulating levels of testosterone, sex hormone binding globulin (SHBG), cortisol, prolactin, norepinephrine and epinephrine during FES assisted resistance exercise in five high spinal cord injured men (SCI) and comparable maximal exercise in five able bodied controls (AB). Mean serum testosterone levels significantly increased with FES-assisted resistance training in SCI and maximal resistance exercise in AB with no significant change in hematocrit or SHBG. Prolactin, cortisol and epinephrine levels were unchanged while norepinephrine levels were significantly increased in SCI and AB. These findings suggest that there is no concern over inadequate physiological androgen response to an exercise stimulus in SCI. The data do not support the previous findings that elevated levels of norepinephrine in autonomic dysreflexia suppress testosterone response to exercise.