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The role of nutrition and performance is well established. Service members' physical and cognitive performance, sleep and mood are impacted by nutritional choices. Although many eating patterns have emerged, consensus among experts recommend a dietary pattern focused on predominantly whole plant-based foods. Adequate intakes of fruits, vegetables, whole grains, beans, legumes, nuts and seeds should be prioritised. Implementation of strategic and intentional fuelling strategies around times of activity maintain adequate energy stores, enhance recovery and protect against training injuries. Carbohydrates are prioritised before, during and after activity or a mission, although the type and amount will vary based on duration and intensity of activity. Protein is generally the focus after activity or a mission and may be included before activity depending on individual tolerance. There are no specific recommendations for fat consumption before, during and after exercise that will improve performance. That said, Service members generally tolerate low-fat meals/snacks prior to exercise, limit fat intake during exercise, may include fat as part of the post exercise meal/snack, and generally consume most fat during the maintenance and growth phase. Careful consideration and planning for food and fluid requirements should be made when Service members are exposed to heat, cold and/or altitude. Operational rations are formulated to meet the nutritional needs of all Service members across a variety of diverse climates, environments and altitudes. Service members may use dietary supplements to improve their performance and need to be aware of available resources to help them make informed decisions.
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PURPOSE: The advantages of minimally invasive inguinal hernia repair (MIHR) over open hernia repair (OHR) continue to be debated. We compared MIHR to OHR by utilizing the Army Physical Fitness Test (APFT) as an outcome measure. METHODS: The APFT is a three-component test scored on a normalized 300 point scale taken semiannually by active-duty military. We identified 1119 patients who met inclusion criteria: 588 in the OHR group and 531 in the MIHR group. Changes in APFT scores, time on post-operative duty restrictions (military profile), and time interval to first post-operative APFT were compared using regression analysis. RESULTS: Postoperatively, no APFT score change difference was observed between the OHR or MIHR groups (- 7.3 ± 30 versus - 5.5 ± 27.7, p = 0.2989). Service members undergoing OHR and MIHR underwent their first post-operative APFT at equal mean timeframes (6.6 ± 5 months versus 6.7 ± 5.1, p = 0.74). No difference was observed for time in months spent on an official temporary duty restriction (military profile) for either OHR or MIHR (0.16 ± 0.16 versus 0.15 ± 0.17, p = 0.311). On adjusted regression analysis, higher pre-operative APFT scores and BMI ≥ 30 were independently associated with reduction in post-operative APFT scores. Higher-baseline APFT scores were independently associated with less time on a post-operative profile, whereas higher BMI (≥ 30) and lower rank were independently associated with longer post-operative profile duration. Higher-baseline APFT scores and lower rank were independently associated with shorter time intervals to the first post-operative APFT. CONCLUSION: Overall, no differences in post-operative APFT scores, military profile time, or time to first post-operative APFT were observed between minimally invasive or open hernioplasty in this military population.
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Hérnia Inguinal , Laparoscopia , Militares , Humanos , Hérnia Inguinal/cirurgia , Herniorrafia , Aptidão Física , Avaliação de Resultados em Cuidados de SaúdeRESUMO
INTRODUCTION: Minimising temporary and permanent disability associated with musculoskeletal conditions (MSK-D) is critical to the mission of the US Army. Prior research has identified potentially actionable risk factors for overall military disability and its MSK-D subset, including elevated body mass index, tobacco use and physical fitness. However, prior work does not appear to have addressed the impact of these factors on MSK-D when controlling for a full range of factors that may affect health behaviours, including aptitude scores that may serve as a proxy for health literacy. Identifying risk factors for MSK-D when providing control for all such factors may inform efforts to improve military readiness. METHODS: We studied 494 757 enlisted Army soldiers from 2014 to 2017 using a combined medical and administrative database. Leveraging data from the Army's digital 'eProfile' system of duty restriction records, we defined MSK-D as the first restriction associated with musculoskeletal conditions and resulting in the inability to deploy or train. We used multivariable Cox proportional hazards regression to assess the associations between incident MSK-D and selected risk factors including aptitude scores, physical fitness test scores, body mass index and tobacco use. RESULTS: Among the subjects, 281 278 (45.14%) experienced MSK-D. In the MSK-D hazards model, the highest effect size was for failing the physical fitness test (adjusted HR=1.63, 95% CI 1.58 to 1.67, p<0.001) compared with scoring ≥290 points. CONCLUSIONS: The analysis revealed the strongest associations between physical fitness and MSK-D. Additional efforts are warranted to determine potential mechanisms for the observed associations between selected factors and MSK-D.
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Militares , Doenças Musculoesqueléticas , Humanos , Fatores de Risco , Aptidão Física , Doenças Musculoesqueléticas/epidemiologia , Doenças Musculoesqueléticas/etiologia , Índice de Massa CorporalRESUMO
The family of heat shock proteins works at the cellular level to protect cells against many chronically and acutely induced stressful conditions. The induction of certain family members, such as HSP70 and HSP90 via a heat shock factor 1 activated pathway, may have broad therapeutic benefits in the treatment of various types of tissue trauma and metabolic diseases. HSPs with their ability to improve cytoprotective functions and enhance tissue regeneration, offer a new potential in treating conditions such as diabetes and obesity. We hypothesized that the plasma levels of HSP70 and/or HSP90 would be significantly lower in obese than non-obese African American men and women. The objective of the study was to provide an analysis of plasma HSP70 and HSP90 concentrations of African American subjects grouped according to widely accepted health risk indices and insulin resistance. Comparisons of HSP70 and HSP90 concentrations by BMI, percent body fat, waist circumference, insulin resistance, plasma cortisol levels and gender were conducted. HSP70 concentration inversely correlated with BMI, percentage body fat, waist circumference, and insulin resistance. No significant correlation was observed for HSP90 concentration with the aforementioned indices. Our results show that high risk health conditions, such as obesity and type-2 diabetes, may be associated with compromised expression of specific heat shock proteins such as HSP70.
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Negro ou Afro-Americano , Diabetes Mellitus Tipo 2/sangue , Proteínas de Choque Térmico HSP70/sangue , Resistência à Insulina/fisiologia , Obesidade/sangue , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Adulto JovemRESUMO
Activation of the hypothalamic-pituitary-adrenal axis leads to secretion of cortisol, which binds to peripheral glucocorticoid receptor and mediates a complex series of metabolic and immune effects. Cortisol also binds to receptors in the hypothalamus and pituitary, and inhibits further secretion of adrenocorticotropic hormone thus preventing an excessive response. Excess glucocorticoid effect is seen in Cushings disease, adrenal adenomas/carcinomas and in glucocorticoid resistance. Within such pathology there are health consequences of excessive glucocorticoid action, including obesity, hypertension, and glucose intolerance or diabetes. We hypothesized that increased glucocorticoid receptor in peripheral tissue might mediate an excess glucocorticoid effect in the absence of increased cortisol secretion. The objective of the study was to investigate the relationship between glucocorticoid receptor density in leukocytes and health risk indices relevant to obesity and diabetes in a sample of Caucasian and African American subjects. Comparison of glucocorticoid receptor concentration with subject body mass index, percentage body fat, waist circumference, insulin resistance, plasma cortisol levels, gender, and lipid profiles were conducted. Increased glucocorticoid receptor density significantly correlated with body mass index, percentage body fat, waist circumference, and insulin resistance. No significant correlation was observed for glucocorticoid receptor density with lipid profiles. Furthermore, no significant differences were observed in glucocorticoid receptor density between Caucasian and African American subjects or male and female participants. Our results show that high risk health conditions, such as obesity and type-2 diabetes, may be associated with a form of hypothalamic-pituitary-adrenal axis dysfunction, characterized by localized leukocyte glucocorticoid receptor over-expression.
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Adiposidade , Diabetes Mellitus Tipo 2/metabolismo , Resistência à Insulina , Leucócitos/metabolismo , Obesidade/metabolismo , Sobrepeso/metabolismo , Receptores de Glucocorticoides/sangue , Adolescente , Adulto , Negro ou Afro-Americano , Índice de Massa Corporal , Estudos de Coortes , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/etnologia , Diabetes Mellitus Tipo 2/fisiopatologia , Feminino , Humanos , Sistema Hipotálamo-Hipofisário/fisiopatologia , Masculino , Pessoa de Meia-Idade , Obesidade/epidemiologia , Obesidade/etnologia , Obesidade/fisiopatologia , Sobrepeso/epidemiologia , Sobrepeso/etnologia , Sobrepeso/fisiopatologia , Sistema Hipófise-Suprarrenal/fisiopatologia , Receptores de Glucocorticoides/biossíntese , Fatores de Risco , Estados Unidos/epidemiologia , População Branca , Adulto JovemRESUMO
PURPOSE: Determine the short-term effects of creatine supplementation on performance of military tasks, thermoregulation, and health risks. METHODS: Male military personnel were randomly assigned to a creatine (CR; N = 8) or a placebo (CON; N = 8) supplementation group. Testing was conducted at baseline, after a 6-day load phase (20 g/d), and after 4 weeks of taking 6 g/d. Measurements included body composition, liver/kidney function tests, core body temperatures during a 10-mile march and 5-mile run, and performance on physical tasks. RESULTS: Serum and urine creatine increased significantly in the CR group. Body mass and number of pull-ups performed increased significantly in the CR group but not the CON group by week 4. No significant differences between the CR and CON groups were found for other performance measures, body composition, core body temperature, or other biochemical measures. CONCLUSION: Creatine supplementation increased body mass and pull-up performance but did not cause acute health problems. Creatine did not increase core temperature compared with placebo under the environmental conditions of the study, and it is unlikely that creatine will enhance the overall readiness or performance of soldiers.
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Temperatura Corporal , Creatina/farmacologia , Militares , Esforço Físico/fisiologia , Adulto , Análise de Variância , Fenômenos Bioquímicos , Composição Corporal , Temperatura Corporal/efeitos dos fármacos , Creatina/administração & dosagem , Método Duplo-Cego , Humanos , Masculino , Inquéritos e Questionários , Estados UnidosRESUMO
Cellular components of innate immunity (NK cells, monocytes and granulocytes) play an important role in early resistance to Listeria monocytogenes in the mouse model. Minimally invasive methods of measuring the bacteriocidal capacity of these cells may be useful as a biomarker of susceptibility in humans. A technique was developed whereby the uptake and survival of L. monocytogenes could be measured in human granulocytes and monocytes using small volumes of peripheral blood. This method used flow cytometry to detect the presence of PKH-2-labeled bacteria within these cells. Survival of bacteria was determined by sorting of infected cells based on a combination of fluorescence and light scattering properties. Considerable variation in bacterial recovery was seen between normal volunteers. There was consistently greater survival of a fully virulent strain of L. monocytogenes within monocytes and granulocytes compared with an isogenic strain lacking the hemolysin, listeriolysin O, when measured at baseline. There was no evidence of longer-term bacterial survival or growth at 2 or 24 h. This technique may be useful for assessment of both host resistance and pathogen virulence.
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Citometria de Fluxo , Granulócitos/imunologia , Listeria monocytogenes/imunologia , Monócitos/imunologia , Fagocitose , Adulto , Separação Celular , Meios de Cultura , Feminino , Corantes Fluorescentes/metabolismo , Granulócitos/microbiologia , Proteínas Hemolisinas/genética , Humanos , Listeria monocytogenes/genética , Listeria monocytogenes/isolamento & purificação , Listeria monocytogenes/patogenicidade , Listeriose/microbiologia , Masculino , Monócitos/microbiologia , Compostos Orgânicos , VirulênciaRESUMO
Perimenstrual breast pain (cyclical mastalgia) is a common problem that can be sufficiently severe to interfere with usual activities, and has been associated with elevated mammography usage in young women. This study was undertaken to replicate clinic-based research on cyclical mastalgia, and to examine the association between this disorder and health-related behaviors and perceived stress. Using random digit dialing throughout Virginia, 874 women aged 18-44 were interviewed. Sixty-eight per cent of women experienced cyclical breast symptoms; 22% experienced moderate to extreme discomfort (classified as cyclical mastalgia). Hormonal contraceptive usage was associated with significantly less mastalgia and premenstrual syndrome (PMS). Smoking, caffeine consumption and perceived stress were associated with mastalgia (odds ratios = 1.52, 1.53 and 1.7, respectively). Young women (under 35 years) with mastalgia were more likely to have had a mammogram (20.2%) than those without mastalgia (9.9%). Most women with this disorder (77.5%) did not have PMS. The prevalence of cyclical mastalgia and its association with mammography replicate clinic-based findings. Associations with smoking and stress had not previously been reported. Prospective research is needed to determine the biopsychosocial factors contributing to this disorder.
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Mama/fisiopatologia , Comportamentos Relacionados com a Saúde , Ciclo Menstrual/fisiologia , Dor/etiologia , Adolescente , Adulto , Feminino , Nível de Saúde , Humanos , Mamografia/estatística & dados numéricos , Dor/epidemiologia , Dor/psicologia , Síndrome Pré-Menstrual/complicações , Prevalência , Índice de Gravidade de Doença , Estresse Psicológico/complicaçõesRESUMO
OBJECTIVE: To determine whether metabolic bone disease plays a role in the cause of femoral neck stress fractures. STUDY DESIGN: Twenty-three patients with femoral neck stress fractures were enrolled prospectively in the study. Examination included computed tomography bone densitometry, trace mineral analysis, and histomorphometric analysis of the iliac crest in thirteen patients who underwent surgical treatment of their stress fractures. A control group of fifteen patients undergoing iliac crest bone grafting for scaphoid nonunions underwent similar examinations. SETTING: Tertiary military medical center. RESULTS: Patients with femoral neck stress fractures had lower bone mineral density than did control patients (p = 0.010), but no trace mineral deficiencies or consistent histomorphometric differences were noted. CONCLUSIONS: Bone mineral density is decreased in patients with femoral neck stress fractures. Despite observations of decreased bone mineral density in the stress fracture group, osteoporosis, as determined by histomorphometry, is not a consistent finding.
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Doenças Ósseas Metabólicas/complicações , Doenças Ósseas Metabólicas/diagnóstico , Fraturas do Colo Femoral/etiologia , Fraturas do Colo Femoral/cirurgia , Fraturas de Estresse/etiologia , Fraturas de Estresse/cirurgia , Absorciometria de Fóton , Adulto , Idoso , Densidade Óssea/fisiologia , Feminino , Fraturas do Colo Femoral/patologia , Seguimentos , Fixação Interna de Fraturas/métodos , Consolidação da Fratura/fisiologia , Fraturas de Estresse/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Estatísticas não Paramétricas , Tomografia Computadorizada por Raios X , Resultado do TratamentoRESUMO
The biological response to stress involves the activation of two main neuroendocrine components, the hypothalamic-pituitary-adrenal axis and the sympathoadrenal medullary systems. Looking at the responses to stressors in a laboratory setting, e.g., cortisol production after exercising on a treadmill, is a valid and controlled way to study how people react to psychological and physical stressors. A common finding in such studies is that individuals respond bimodally to stress. More recently, researchers have been interested in the possible reasons why healthy individuals exhibit differential reactivity to stressors. The literature on the neuroendocrine responses to stress, with a particular focus on investigations of individual reactivity to psychological and physical stressors, is reviewed.
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Estresse Fisiológico/fisiopatologia , Exercício Físico/fisiologia , Hemodinâmica/fisiologia , Hormônios/sangue , HumanosRESUMO
We recently reported that in 30-50% of healthy men and women the release of ACTH and cortisol stimulated by exercise is not suppressed by prior administration of a 4-mg dose of dexamethasone (DEX). We now explore other potential differences between these subjects and those whose exercise response was suppressed by examining the effect of a smaller, 1-mg, dose of DEX on exercise-stimulated ACTH and cortisol. Men (n = 15) and women (n = 9) were studied during three high intensity exercise tests: one after taking placebo, one after taking 1 mg DEX, and one after taking 4 mg DEX. Before participation, subjects underwent a test for classification as either a high (HR; n = 10) or low (LR; n = 14) reactor and a maximal exercise test to assess maximal aerobic capacity. Distinct dose-related reductions in plasma concentrations of ACTH, cortisol, and dehydroepiandrosterone (DHEA) were noted for HR under the treatment conditions, whereas both doses of DEX blocked ACTH, cortisol, and DHEA release in LR. Furthermore, basal plasma cortisol, DHEA, and DHEA sulfate were significantly higher in HR compared to LR. Thus, there are inherent basal and stress-reactive differences in HR and LR, and these differences may be useful in constructing a model for the mechanisms and physiological regulation of hypothalamic-pituitary-adrenal axis activation. The question of whether these differences in reactivity of the ACTH-cortisol axis between the HR and LR groups have implications for individual short term function or long term health remains to be answered.
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Dexametasona/farmacologia , Sistema Endócrino/fisiologia , Exercício Físico/fisiologia , Glucocorticoides/farmacologia , Hormônio Adrenocorticotrópico/sangue , Adulto , Metabolismo Basal/efeitos dos fármacos , Metabolismo Basal/fisiologia , Glicemia/metabolismo , Citocinas/sangue , Desidroepiandrosterona/sangue , Sistema Endócrino/efeitos dos fármacos , Teste de Esforço , Feminino , Humanos , Hidrocortisona/sangue , Imunidade/efeitos dos fármacos , Imunidade/fisiologia , Interleucina-6/metabolismo , Ácido Láctico/sangue , Masculino , Sistemas Neurossecretores/efeitos dos fármacos , Sistemas Neurossecretores/fisiologia , Consumo de Oxigênio/efeitos dos fármacos , Consumo de Oxigênio/fisiologiaRESUMO
PURPOSE: Recent work indicates that among the normal population, persons can be classified as low (LR) or high (HR) stress responders based on hypothalamic-pituitary-adrenal (HPA) axis responses to high-intensity exercise. We studied whether differential activation of the HPA axis affected cytokine production and expression of selected lymphocyte subsets in HR and LR in response to high-intensity exercise after placebo and dexamethasone (DEX; 4 mg). METHODS: Healthy HR (N = 12) and LR (N = 10) underwent two exercise tests at 90% of VO2max, 8 h after placebo or DEX. Expression of lymphocyte surface markers (CD3+, CD4+, CD8+, CD56+), adhesion molecule markers (intercellular adhesion molecule-1/ICAM-1: CD54+ and L-selectin: CD62L+), and concentrations of plasma interleukin 6 (IL-6) were examined before and after exercise. RESULTS: Baseline percentages of CD8+ and CD56+ cells were significantly higher, and concentrations of IL-6 and percentages of CD4+ cells were significantly lower in HR as compared with LR. The percentage of CD54+ and CD62L+ cells was not significantly different in HR and LR. DEX significantly reduced the percentage of CD3+ and CD4+ and increased the percentage of CD8+ and CD56+ subsets; the percent of cells expressing CD54+ increased, whereas CD62L+ decreased. Exercise-induced changes in the percentage of lymphocyte subsets were similar to those induced by DEX. CONCLUSION: In summary, HR and LR have different baseline patterns of IL-6 and lymphocyte subsets, which may reflect differential sensitivity to endogenous glucocorticoids. However, exogenous glucocorticoids induced similar patterns of lymphocyte expression in HR and LR.
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Dexametasona/farmacologia , Exercício Físico/fisiologia , Sistema Hipotálamo-Hipofisário/fisiologia , Subpopulações de Linfócitos/fisiologia , Sistema Hipófise-Suprarrenal/fisiologia , Moléculas de Adesão Celular/análise , Feminino , Humanos , MasculinoRESUMO
Previous studies indicate that tyrosine may prove useful in promoting improved performance in situations in which performance is compromised by stress. To extend the generality of previous tyrosine findings, the present study examined the effects of tyrosine ingestion on performance during both a Multiple Task and a Simple Task battery. The multiple task battery was designed to measure working memory, arithmetic skills, and visual and auditory monitoring simultaneously, whereas the simple task battery measured only working memory and visual monitoring. Ten men and 10 women subjects underwent these batteries 1 h after ingesting 150 mg/kg of l-tyrosine or placebo. Administration of tyrosine significantly enhanced accuracy and decreased frequency of list retrieval on the working memory task during the multiple task battery compared with placebo. However, tyrosine induced no significant changes in performance on the arithmetic, visual, or auditory tasks during the Multiple Task, or modified any performance measures during the Simple Task battery. Blood levels of ACTH and cortisol were not, but heart rate and blood pressure were significantly increased during the performance tasks. The present results indicate that tyrosine may sustain working memory when competing requirements to perform other tasks simultaneously degrade performance, and that supplemental tyrosine may be appropriate for maintaining performance when mild to severe decrements are anticipated.
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Memória de Curto Prazo/efeitos dos fármacos , Tirosina/farmacologia , Hormônio Adrenocorticotrópico/sangue , Adulto , Atenção/efeitos dos fármacos , Percepção Auditiva/efeitos dos fármacos , Catecolaminas/sangue , Glândulas Endócrinas/efeitos dos fármacos , Feminino , Hemodinâmica/efeitos dos fármacos , Humanos , Masculino , Desempenho Psicomotor/efeitos dos fármacos , Estimulação Química , Tirosina/sangue , Percepção Visual/efeitos dos fármacosRESUMO
The objectives of the study were to determine regional changes in body composition, energy expenditure by means of doubly labeled water, and net energy balance during exposure to high and extreme altitudes (5,300-8,848 m). This study focuses on a subset of subjects who consumed the doubly labeled water (three base camp personnel and seven climbers). Regional body composition was determined by measuring skinfold thicknesses and circumferences at 10 different sites on the body. Energy expenditure was measured by doubly labeled water excretion. Discrepancies between actual energy expenditure and data obtained from diet records and body weight changes suggested a chronic underreporting of dietary energy intake, especially by those subjects who reached the highest altitudes. This underreporting may be due in part to diminished cognition or to a preferential focus on survival, rather than on filling out diet records accurately. Mean adjusted dietary intakes were 10.50 +/- 0. 65 MJ/d (2510 +/- 155 kcal/d) for those who remained at base camp, and 20.63 +/- 6.56 MJ/d (4931 +/- 1568 kcal/d) for those who climbed above base camp. Energy expenditure averaged 2.5-3.0 times sea level resting energy expenditure. Differential changes in regional body composition suggested a preferential loss of fat mass and a relative sparing of muscle mass, despite insufficient energy intake to maintain body weight.
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Tecido Adiposo/metabolismo , Composição Corporal , Metabolismo Energético , Montanhismo/fisiologia , Músculos/metabolismo , Adulto , Altitude , Óxido de Deutério/metabolismo , Dieta , Registros de Dieta , Ingestão de Energia , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Healthy men exhibit a differential hypothalamic-pituitary-adrenal axis (HPA) response to exercise stress and fall into two groups: high responders (HR) and low responders (LR). The present study examined whether HR to physical stress also exhibit higher HPA reactivity to psychological stress than LR. We examined 14 HR and 13 LR classified based on their ACTH responses to high intensity exercise after pretreatment with dexamethasone. Both groups were of similar age, height, weight, and fitness level. Trait anxiety scores on the Spielberger Trait Anxiety Scale were not different. Subjects underwent a psychological stress test consisting of an interview and mental arithmetic. This test raised heart rate, blood pressure, and plasma ACTH and cortisol levels in both HR and LR. HR tended to have higher heart rates and blood pressures in anticipation of the psychological stress test than LR. ACTH responses of HR were higher, although not significantly, throughout the psychological stress test than LR. HR had a significantly (P < 0.05) greater net integrated cortisol response to the psychological stress than LR. This suggests that the adrenal cortexes of the HR are hypertropic and/or hypersensitive to ACTH. We conclude that men who are highly responsive to exercise stress are also highly responsive to psychological stress.
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Sistema Hipotálamo-Hipofisário/fisiopatologia , Sistema Hipófise-Suprarrenal/fisiopatologia , Estresse Fisiológico/fisiopatologia , Estresse Psicológico/fisiopatologia , Hormônio Adrenocorticotrópico/sangue , Adulto , Pressão Sanguínea/fisiologia , Teste de Esforço , Frequência Cardíaca/fisiologia , Humanos , Hidrocortisona/sangue , Masculino , Meio SocialRESUMO
PURPOSE: The study was undertaken to determine whether acute supplementation with zinc or vitamin E would modify neuroendocrine responses to physiologic stress. METHODS: Specifically, the effects of exhaustive running on blood glucose, lactate, ACTH, cortisol, growth hormone, prolactin, catecholamine, and interleukin 6 (IL-6) concentrations were determined in 10 eumenorrheic runners after supplementation with zinc (25 mg), vitamin E (400 IU), or placebo. Subjects ran at 65-70% of their VO2max, to exhaustion, on a treadmill during the follicular phase of their menstrual cycles over three cycles. RESULTS: There were no significant differences associated with supplementation for any of the hormonal and metabolic measures. Exercise, however, significantly (P<0.05) increased plasma lactate, ACTH, prolactin, and catecholamine concentrations, all of which peaked immediately after exercise (POST). Plasma cortisol concentrations were significantly (P<0.05) elevated at POST, and a further increase was noted 1 h after exercise. IL-6 concentrations rose linearly throughout exercise and reached peak values at POST. Exercise-induced changes were transient in that all measures returned to baseline within 24 h. CONCLUSIONS: Acute supplementation with zinc or vitamin E did not influence the effects of exhaustive running on metabolic and endocrine responses in women. The effects of chronic supplementation on neuroendocrine responses to exercise remain to be determined.
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Suplementos Nutricionais , Sistemas Neurossecretores/fisiologia , Corrida/fisiologia , Vitamina E , Zinco , Hormônio Adrenocorticotrópico/sangue , Adulto , Glicemia/análise , Catecolaminas/sangue , Método Duplo-Cego , Feminino , Humanos , Hidrocortisona/sangue , Interleucina-6/sangue , Ácido Láctico/sangueRESUMO
OBJECTIVE: To investigate the influence of various biological, socioeconomic, and behavioral factors on premenstrual syndrome (PMS). DESIGN: Random-digit dialing technique. Of 7900 calls from all area codes, exchanges, and 2 digits known to be open in Virginia, with a pair of random digits, 1700 women were eligible for telephone interviews. A total of 874 women completed interviews, for a response rate of 67%. SETTING: State of Virginia. PATIENTS OR OTHER PARTICIPANTS: All women between the ages of 18 and 44 years and living in Virginia between August 1 and September 15, 1994, were eligible. MAIN OUTCOME MEASURES: Scores on Menstrual Distress Questionnaire, biological variables, lifestyle behaviors, socioeconomic status, and menstrual and reproductive history. RESULTS: Of the 874 women, 8.3% (95% confidence interval, 6.4%-10.2%) experienced PMS. Adjusted prevalence odds ratios for perceived stress and alcohol intake were 3.7 and 2.5, respectively, in women with PMS. Women with PMS were 2.9 times more likely to be physically active than women without PMS. Younger women, black women, and women with longer menses were more likely to have PMS. CONCLUSIONS: Scores on the stress scale and alcohol intake support the concept that PMS is stress related; intervention strategies to cope with stress may be effective. Further study will be required to determine the influence of race on PMS and whether women with PMS exercise more regularly than women without PMS because they believe exercise is effective in attenuating their symptoms.
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Síndrome Pré-Menstrual/etiologia , Adulto , Feminino , Humanos , Estilo de Vida , Razão de Chances , Síndrome Pré-Menstrual/epidemiologia , Síndrome Pré-Menstrual/fisiopatologia , Síndrome Pré-Menstrual/psicologia , Prevalência , Risco , Fatores de Risco , Virginia/epidemiologiaRESUMO
The role that metabolic products play in regulating the hypothalamic-pituitary-adrenal (HPA) axis during strenuous exercise is speculative. This investigation examined the extent to which lactic acid, a major metabolite of anaerobic exercise, directly affects hypothalamic-pituitary function. Specifically, beta-endorphin secretion was measured from AtT-20 (D-16) mouse corticotroph tumor cells treated either acutely (15 min - 180 min) or chronically (1 day - 3 day) with physiologic levels of lactate (0. 5 x 10-3 M to 5 x 10-2 M) or lactate in combination with the corticotroph releasing factors: corticotroph releasing hormone (CRH), arginine vasopressin (AVP), norepinephrine and/or epinephrine. Findings with AtT-20 cell cultures were shown to be representative of responses in primary cultures of rat anterior pituitary. Lactic acid did not alter the spontaneous release of beta-endorphin by AtT-20 cells under either acute or chronic conditions. While CRH, norepinephrine, and epinephrine evoked significant increases in beta-endorphin release, lactate, in combination with these secretagogues did not alter their effects. Similarly, lactic acid failed to alter basal or stimulated release of beta-endorphin by primary cultures of rat anterior pituitary. The addition of lactate (3 x 103 M) to rat hypothalamic explants did, however, produce a modest but significant reduction in spontaneous CRH release, suggesting that lactate may facilitate the return to basal secretion following exercise. The present findings show that physiologic concentrations of lactate have no effect, either alone or in combination with other pituitary secretagogues, on corticotroph secretion. Whereas a physiologic action for lactate within the hypothalamus is possible, the present findings indicate that lactate is an inhibitor of CRH release. Thus, lactate does not appear to play a direct role in the profound activation of the HPA axis that occurs in response to strenuous exercise.
Assuntos
Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/fisiologia , Ácido Láctico/farmacologia , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Sistema Hipófise-Suprarrenal/fisiologia , Animais , Arginina Vasopressina/administração & dosagem , Arginina Vasopressina/farmacologia , Linhagem Celular , Hormônio Liberador da Corticotropina/administração & dosagem , Hormônio Liberador da Corticotropina/metabolismo , Hormônio Liberador da Corticotropina/farmacologia , Interações Medicamentosas , Epinefrina/administração & dosagem , Epinefrina/farmacologia , Ácido Láctico/administração & dosagem , Masculino , Camundongos , Norepinefrina/administração & dosagem , Norepinefrina/farmacologia , Esforço Físico/fisiologia , Ratos , Ratos Sprague-Dawley , beta-Endorfina/metabolismoRESUMO
Exercise promotes escape of ACTH and cortisol from suppression by dexamethasone (DEX) in some healthy men and women. To determine whether stimulus strength, diurnal rhythmicity, or gender influences neuroendocrine escape during DEX suppression, we studied men (n = 5) and women (n = 5) during high intensity exercise tests after taking 4 mg DEX: two tests (one at 90% and one at 100% of maximal aerobic capacity) were conducted in the morning and two were performed in the afternoon on nonconsecutive days. Plasma ACTH and cortisol showed significantly greater increases with the 100% compared to the 90% intensity exercise (ACTH: 90%, 2 +/- 0.4; 100%, 3 +/- 0.5 pmol/L; cortisol: 90%, 53 +/- 5.3; 100% 93 +/- 23.6 nmol/L). Plasma cortisol responses were significantly higher in women than in men (P < 0.01). Plasma arginine vasopressin (AVP) exhibited significant intensity-dependent increases, with higher responses in women than men (P < 0.01). In conclusion, despite high dose glucocorticoid pretreatment, intense exercise can override the glucocorticoid negative feedback of hypothalamic-pituitary-adrenal activation in most normal men and women. This ability to override cortisol negative feedback inhibition may relate to the magnitude of the AVP response, the potency/specificity of the stressor to elicit a CRH/AVP response, and/or the sensitivity of the glucocorticoid negative feedback system at the time of the stress.