***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: PURPOSE The purpose of this study was to evaluate the effect of hormone replacement therapy ( HRT ) on the acute and chronic hormonal responses to resistance exercise in post-menopausal women . METHODS Thirty-two post-menopausal women were recruited for this study ; 16 who were currently using HRT and 16 who were not using HRT .  Subjects in both the HRT and NHRT groups were r and omly assigned to either a resistance training group ( N = 16 ; 8 HRT and 8 NHRT ) or a control group ( N = 16 ; 8 HRT and 8 NHRT ) . The training group completed a supervised resistance training program three times a week for 12 weeks . To evaluate changes in hormone levels , resting blood sample s were drawn at weeks 0 , 4 , and 13 of the program . In addition , at weeks 0 and 13 , post-exercise blood sample s were drawn in order to examine the hormone response to an acute bout of resistance exercise . Sample s were analyzed for serum growth hormone ( GH ) , insulin-like growth factor-1 ( IGF-1 ) , testosterone , estradiol , dehydroepi and rosterone ( DHEA ) , and cortisol . RESULTS There were no significant changes in resting hormone levels between weeks 0 , 4 , and 13 of the training program . There was a significant week-by-group interaction for DHEA ( P < 0.05 ) and cortisol ( P < 0.05 ) with the NHRT-training group having a greater post-exercise increase in DHEA and cortisol after training . Overall , the post-exercise GH levels were significantly greater than pre-exercise ( P < 0.05 ) or recovery levels ( P < 0.01 ) . There were no significant differences between HRT and NHRT groups in the acute hormone response to exercise . CONCLUSION These results indicate that HRT will not have an effect on the acute or chronic hormone response to a recreational resistance training program in post-menopausal women Elevated circulating estrogens and a sedentary lifestyle increase risk for breast cancer .  The effect of exercise on circulating estrogens in sedentary postmenopausal women is unknown . The objective of this study was to examine the effects of a 12-month moderate-intensity exercise intervention on serum estrogens . We r and omly assigned 173 sedentary , overweight ( body mass index > 24.0 kg/m(2 ) , body fat > 33 % ) , postmenopausal women , ages 50 - 75 years , not using hormone therapy , living in the Seattle , Washington , area for the next year , and willing to be r and omly assigned to an exercise intervention or stretching control group . The exercise intervention included facility and home-based exercise ( 45 min , 5 days/week moderate intensity sports/recreational exercise ) . A total of 170 ( 98.3 % ) women completed the study with exercisers averaging 171 min/week of exercise . After 3 months , exercisers experienced declines in estrone , estradiol , and free estradiol of 3.8 , 7.7 , and 8.2 % , respectively , versus no change or increased concentrations in controls ( P = 0.03 , 0.07 , and 0.02 , respectively ) . At 12 months , the direction of effect remained the same , although the differences were no longer statistically significant . The effect was limited to women who lost body fat : women whose percentage of body fat [ by dual energy x-ray absortiometry ( DEXA ) ] decreased by > /== " BORDER="0">2 % had statistically significant ( comparing exercisers versus controls ) decreases at 12 months of 11.9 , 13.7 , and 16.7 % for serum estrone , estradiol , and free estradiol , respectively . We concluded that a 12-month moderate-intensity exercise intervention in postmenopausal women result ed in significant decreases in serum estrogens . The association between increased physical activity and reduced risk for postmenopausal breast cancer may be partly explained by effects on serum estrogens BACKGROUND Women with polycystic ovary syndrome ( PCOS ) present with vascular abnormalities , including elevated markers of endothelial dysfunction . There is limited evidence for the effect of lifestyle modification and weight loss on these markers . The aim of this study was to determine if 20 weeks of a high-protein energy-restricted diet with or without exercise in women with PCOS could improve endothelial function . METHODS This is a secondary analysis of a subset of 50 overweight/obese women with PCOS ( age : 30.3 ± 6.3 years ; BMI : 36.5 ± 5.7 kg/m(2 ) ) from a previous study . Participants were r and omly assigned by computer generation to one of three 20-week interventions : diet only ( DO ; n = 14 , ≈ 6000 kJ/day ) , diet and aerobic exercise ( DA ; n = 16 , ≈ 6000 kJ/day and five walking sessions/week ) and diet and combined aerobic-resistance exercise ( DC ; n = 20 , ≈ 6000 kJ/day , three walking and two strength sessions/week ) . At Weeks 0 and 20 , weight , markers of endothelial function [ vascular cell adhesion molecule-1 ( sVCAM-1 ) , inter-cellular adhesion molecule-1 ( sICAM-1 ) , plasminogen activator inhibitor-1 ( PAI-1 ) and asymmetric dimethylarginine ( ADMA ) ] , insulin resistance and hormonal profile were assessed . RESULTS All three treatments result ed in significant weight loss ( DO 7.9 ± 1.2 % , DA 11.0 ± 1.6 % , DC 8.8 ± 1.1 ; P < 0.001 for time ; P = 0.6 time × treatment ) . sVCAM-1 , sICAM-1 and PAI-1 levels decreased with weight loss ( P≤ 0.01 ) , with no differences between treatments ( P ≥ 0.4 ) . ADMA levels did not change significantly ( P = 0.06 ) . Testosterone , sex hormone-binding globulin and the free and rogen index ( FAI ) and insulin resistance also improved ( P < 0.001 ) with no differences between treatments ( P ≥ 0.2 ) . Reductions in sVCAM-1 were correlated to reductions in testosterone ( r = 0.32 , P = 0.03 ) and FAI ( r = 0.33 , P = 0.02 ) as well as weight loss ( r= 0.44 , P = 0.002 ) . Weight loss was also associated with reductions in sICAM-1 ( r= 0.37 , P = 0.008 ) . CONCLUSIONS Exercise training provided no additional benefit to following a high-protein , hypocaloric diet on markers of endothelial function in overweight/obese women with PCOS Polycystic ovary syndrome ( PCOS ) , the most common endocrine disorder in women of reproductive age , is characterized by hyper and rogenism , oligo/amenorrhea , and polycystic ovaries . We aim ed to determine whether low-frequency electro-acupuncture ( EA ) would decrease hyper and rogenism and improve oligo/amenorrhea more effectively than physical exercise or no intervention . We r and omized 84 women with PCOS , aged 18 - 37 yr , to 16 wk of low-frequency EA , physical exercise , or no intervention . The primary outcome measure changes in the concentration of total testosterone ( T ) at week 16 determined by gas and liquid chromatography-mass spectrometry was analyzed by intention to treat . Secondary outcome measures were changes in menstrual frequency ; concentrations of and rogens , estrogens , and rogen precursors , and glucuroni date d and rogen metabolites ; and acne and hirsutism . Outcomes were assessed at baseline , after 16 wk of intervention , and after a 16-wk follow-up . After 16 wk of intervention , circulating T decreased by -25 % , and rosterone glucuronide by -30 % , and and rostane-3α,17β-diol-3-glucuronide by -28 % in the EA group ( P = 0.038 , 0.030 , and 0.047 , respectively vs. exercise ) ; menstrual frequency increased to 0.69/month from 0.28 at baseline in the EA group ( P = 0.018 vs. exercise ) . After the 16-wk follow-up , the acne score decreased by -32 % in the EA group ( P = 0.006 vs. exercise ) . Both EA and exercise improved menstrual frequency and decreased the levels of several sex steroids at week 16 and at the 16-wk follow-up compared with no intervention . Low-frequency EA and physical exercise improved hyper and rogenism and menstrual frequency more effectively than no intervention in women with PCOS . Low-frequency EA was superior to physical exercise and may be useful for treating hyper and rogenism and oligo/amenorrhea Background : It is hypothesized that exercise can lead to a decrease in breast cancer risk through several hormonal and nonhormonal mechanisms . The WISER ( Women In Steady Exercise Research ) study investigated the effects of aerobic exercise on premenopausal sex hormone levels . Methods : Three hundred ninety-one sedentary , healthy , young eumenorrheic women were r and omized either into an exercise intervention of 30 minutes of aerobic exercise 5 times a week for approximately 16 weeks ( n = 212 ) or into a control group ( n = 179 ) . Serum levels of estradiol , estrone sulfate , testosterone , and sex hormone – binding globulin ( SHBG ) , all in the midfollicular phase , and of progesterone , in the midluteal phase , were measured at baseline and at the end of the 16-week period . Results : Compared with the controls ( n = 153 ) , exercisers ( n = 166 ) experienced significant increases in aerobic fitness , lean body mass , and decreases in percent body fat . There were no significant changes in body weight and menstrual cycle length between or within groups . Progesterone decreased significantly in exercisers ; however , this reduction was similar to that of the control group . No significant changes between or within groups were found for any of the other sex hormones or SHBG . Conclusions : In premenopausal women , 16 weeks of 150 minutes per week of moderate aerobic exercise in young women did not significantly alter sex hormone or SHBG levels . Impact : Any favorable effects that moderate aerobic exercise without an associated weight change may have on breast cancer risk in premenopausal women are unlikely to be a consequence of changes in levels of sex hormones or SHBG . Cancer Epidemiol Biomarkers Prev ; 20(6 ) ; 1098–106 . © 2011 AACR Physical activity has been proposed as one strategy to enhance bone mineral acquisition ; however , the basic mechanisms of this effect are not fully understood . The purpose of this study was to investigate the effect of 12 weeks of resistance training on hormones of bone formation in young sedentary women . Twenty sedentary females ( aged 25.3 ± 3.2 years ; ±SD ) volunteered to participate in this study . The subjects were r and omly assigned to a training group ( n = 10 ) or control group ( n = 10 ) . Subjects executed eight resistance exercises selected to stress the major muscle groups in the following order : chest press , leg extension , shoulder press , leg curls , latissimus pull down , leg press , arm curls , and triceps extension . Resistance training consisted of 50–60 min of circuit weight training per day , 3 days a week , for 12 weeks . This training was circularly performed in eight stations and included two to four sets with 8–12 maximal repetitions at 65–80 % of one-repetition maximum in each station . After 12 weeks , the training group had a significant increase ( P < 0.05 ) in the growth hormone , estrogen , parathyroid hormone and testosterone compared to the control group . The results showed that insulin-like growth factor I levels did not change significantly in response to resistance training . In conclusion , the results suggest that resistance training with specific intensity and duration utilized in this study increases the hormones of bone formation in young sedentary women CONTEXT Polycystic ovary syndrome ( PCOS ) presents in adolescence , and obesity is a common finding . The benefits and risks of alternate approaches to the management of PCOS in obese adolescent women are not clear . OBJECTIVE We investigated the effects of metformin , oral contraceptives ( OCs ) , and /or lifestyle modification in obese adolescent women with PCOS . DESIGN Two small , r and omized , placebo-controlled clinical trials were performed . PATIENTS AND PARTICIPANTS A total of 79 obese adolescent women with PCOS participated . INTERVENTIONS In the single treatment trial , subjects were r and omized to metformin , placebo , a lifestyle modification program , or OC . In the combined treatment trial , all subjects received lifestyle modification and OC and were r and omized to metformin or placebo . MAIN OUTCOME MEASURES Serum concentrations of and rogens and lipids were measured . RESULTS Lifestyle modification alone result ed in a 59 % reduction in free and rogen index with a 122 % increase in SHB 
    Output:
    
Subgroup analyses suggest that this effect is independent of menopausal status and is more noticeable for non-obese women and for high intensity exercise .
Meta- analysis for secondary outcomes found that physical activity induces a statistically significant decline of free testosterone , and rostenedione , dehydroepi and rosterone – sulfate and adiposity markers , while a significant increase of SHBG was observed .
Conclusions Although the effect is relatively modest , physical activity induces a decrease in circulating sex hormones and this effect is not entirely explained by weight loss .
The findings emphasize the benefits of physical activity for women