Energy deficit increases hepcidin and exacerbates declines in dietary iron absorption following strenuous physical activity: a randomized-controlled cross-over trial

Declines in Dietary Iron Absorption Following Simulated Military Operations Are Exacerbated by Energy Deficit

To assess the total daily energy expenditure (TDEE), milk output and physical activity level (PAL) of chronically malnourished lactating women using the doubly labelled water method (DLW). Prospective, longitudinal study designed to assess the extent of malnutrition and energetics of lactating tea workers and nontea workers. North-east Bangladesh on women working and living in the same tea estates. Of an original cohort of 150 lactating women, 30 were selected to participate in this study when they were at about 12 months postpartum. One mother subsequently dropped out. On day 1 each women provided a urine sample, was administered a dose of DLW and 6 h later provided another sample. Further urine samples were collected for 21 subsequent days. In addition, every 5 days the mother provided a milk sample and at the same time her baby provided a urine sample. Mean (s.d.) BMI was 17.4 (1.63). Mean TDEE and PAL were significantly higher in workers than nonworkers (8.42 (1.38) and 6.83 (2.09) MJ/day, P = 0.02 and 1.92 (0.34) and 1.59 (0.44), P = 0.03, respectively). Mean milk output was similar in the two groups (672 (180) ml and 749 (189) ml in workers and nonworkers, respectively). Based on international BMI cutoffs, 79% of mothers were suffering from some degree of chronic energy deficiency. A total of 35% of workers and 17% of nonworkers were engaged in strenuous physical activity. The mean milk output of both workers and nonworkers was not different and was high especially as most of the mothers were about 12 months postpartum. No relationship was found between menses return and any of the variables studied. World Health Organization, Nestle Foundation, UNICEF.

Background. Evidence has accumulated showing that physical activity reduces breast cancer risk. Whether risk reduction pertains to all breast cancer or specific receptor-defined subtypes is unclear. Moreover, few studies have examined whether changes in the amount of physical activity during adulthood influence breast cancer risk. Methods. Among 108,907 women, ages 22 to 79 years with no history of breast cancer when they joined the California Teachers Study in 1995-1996 (baseline), 5,578 women were diagnosed with invasive breast cancer during follow-up through December, 2011. Subtypes were defined by the expression status of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Cox proportional hazards models were fit to data to estimate adjusted hazard rate ratios (HRs) and 95% confidence intervals (CIs) associated with long-term and recent (within 3 years of baseline) recreational physical activity. Among 54,690 women who provided updated information on physical activity in 2005-2008, we also assessed whether changes in the level of physical activity since baseline influenced breast cancer risk (654 cases diagnosed during follow-up). Results. Long-term and recent recreational physical activity were inversely associated with risk of triple negative breast cancer (TNBC, both Ptrend ≤ 0.05), but not other subtypes (all Ptrend ≥ 0.07). The reduced risk of TNBC was limited to strenuous physical activity. A 50% (HR = 0.50, 95% CI = 0.29-0.86) lower risk of TNBC was observed among women in the highest (≥5.01 h/wk) versus lowest category (≤0.50 h/wk) of long-term strenuous recreational physical activity; this was not modified by baseline body mass index (<25 kg/m2 vs. ≥25 kg/m2), menopausal hormone therapy (MHT) use (never vs. ever), or the cessation of MHT use (former vs. recent). An inverse association between strenuous recreational physical activity and risk of luminal A-like (ER+ or PR+ plus HER2-) breast cancer was observed only among former MHT users (Ptrend: 0.02 for both long-term and baseline strenuous physical activity). Women who increased their level of recent recreational physical activity from ≤0.50 h/wk at baseline to ≥4.51 h/wk in 2005-2008 had a 32% (HR = 0.68, 95% CI = 0.47-0.99) lower risk of breast cancer overall than those who stayed at the lowest level. Conclusions. This study suggests that long-term strenuous physical activity is associated with lower risk of TNBC. Further, it shows that substantially increasing the amount of total recreational physical activity in adulthood decreases the risk of breast cancer. Citation Format: Huiyan Ma, Jessica Clague, Xinxin Xu, Yani Lu, Kayo Togawa, Sophia S. Wang, Christina A. Clarke, Eunjung Lee, Hannah L. Park, Jane Sullivan-Halley, Susan Neuhausen, Leslie Bernstein. Long-term and recent recreational physical activity reduces risk of triple negative and other subtypes of invasive breast cancer in the California Teachers Study. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 872. doi:10.1158/1538-7445.AM2015-872

275 undergraduate university students were asked to complete a battery concerning their health complaints, perceived stress, strenuous physical activity, and personality ("Big Five" traits). An hierarchical regression showed that Stress and Strenuous Physical Activity Participation, but not Personality, predicted the Number of Health Complaints in this sample. Also, there was a significant interaction for Stress by Strenuous Activity indicating individuals who did not frequently engage in strenuous leisure-time physical activity reported more health complaints than those who did. This finding corroborates the notion that physical activity (or fitness) may serve to attenuate the relation between stress and health complaints.

A Prolonged Bout of Running Increases Hepcidin and Decreases Dietary Iron Absorption in Trained Female and Male Runners

Fibrinolysis was studied in 10 alpinists during regular physical activity of different intensity. Blood was sampled at rest and after exposure to submaximal workload on the treadmill on three occasions: before and after 6 months physical conditioning (moderate physical activity), and after 6 weeks of an alpinistic expedition (strenuous physical activity). Measurements included submaximal working capacity, fibrinogen, euglobulin clot lysis time (ELT), whole plasma clot lysis time, and estimations derived from ELT--percent increase in fibrinolytic activity after exercise (RFS), and absolute increase in fibrinolytic activity after exercise (PAR). Regular moderate activity increased the resting level of ELT, but strenuous activity decreased is. After each treadmill testing, a marked increase in fibrinolytic activity was observed. RFS was unaltered at all three testings. PAR increased after moderate activity, but decreased after strenuous activity. The results indicate that regular physical activity can lead from enhanced to decreased resting activity of plasminogen activator in blood. It is presumed that increased release of activator during prolonged stress causes partial depletion of endothelial stores with the consequence of decreased activator activity in the blood.

Long-term physical activity is associated with lower breast cancer risk. Little information exists on its association with subsequent survival. California Teachers Study cohort members provided information in 1995-1996 on long-term (high school through age 54 years) and recent (past 3 years) participation in moderate and strenuous recreational physical activities. The 3,539 women diagnosed with invasive breast cancer after cohort entry and through December 31, 2004, were followed through December 31, 2005. Of these, 460 women died, 221 from breast cancer. Moderate and strenuous physical activities were combined into low (<or=0.50 h/wk/y of any activity), intermediate (0.51-3.0 h/wk/y of moderate or strenuous activity but no activity >3.0 h/wk/y), or high activity (>3.0 h/wk/y of either activity type). Multivariable relative risks (RR) and 95% confidence intervals (95% CI) for mortality were estimated using Cox proportional hazards methods, adjusting for race/ethnicity, estrogen receptor status, disease stage, and baseline information on comorbidities, body mass index, and caloric intake. Women with high or intermediate levels of long-term physical activity had lower risk of breast cancer death (RR, 0.53; 95% CI, 0.35-0.80; and RR, 0.65; 95% CI, 0.45-0.93, respectively) than women with low activity levels. These associations were consistent across estrogen receptor status and disease stage, but were confined to overweight women. Deaths due to causes other than breast cancer were related only to recent activity. Consistent long-term participation in physical activity before breast cancer diagnosis may lower risk of breast cancer death, providing further justification for public health strategies to increase physical activity throughout the lifespan.

Strenuous physical activity can cause muscle damage which is marked by an increase in creatine kinase levels. One of the strategies to prevent muscle damage is to consume antioxidants and anti-inflammatory. Beetroot (Beta vulgaris L.) is known to have antioxidant and anti-inflammatory activity. The aim of this study was to determine the effect of acutely giving beetroot juice on creatine kinase levels after strenuous physical activity. The research sample used 20 trained males. The sample was divided into two groups (Experiment = 10; Placebo = 10). The pre-test was done by checking creatine kinase levels before engaging in strenuous physical activity. After doing strenuous physical activity by running on a treadmill with an intensity of 90-100% for 30 minutes, the experimental group was given 300 ml of beetroot juice (BRJ) every day for 3 days, while the control group was given a placebo drink. Creatine kinase levels were measured immediately, 24 hours, 48 hours, and 72 hours after strenuous physical activity. The results showed that CK levels decreased significantly 24 hours, 48 hours and 72 hours after strenuous physical activity in the BRJ group compared to the placebo group (p <0.05) The conclusion of this study is that giving BRJ acutely after doing strenuous physical activity can reduce creatine kinase levels in trained male athletes. Acute JBR supplementation in this study can help reduce muscle damage due to strenuous physical exercise through nutritional interventions

Venous thromboembolism among physically active young adult females

Objectives: The aim of the present study was to investigate the relationships of different types of quality of life to strenuous and light physical activity in old age. Methods: The Swedish SNAC-Blekinge baseline database, consisting of data on 585 men and 817 women 60–96 years of age, was utilized. The independent variables were light and strenuous physical activity. Four dependent variables concerned with various quality of life components were employed (well-being, engagement, emotional support and social anchorage). Age, gender, functional ability and co-morbidity were included as possible confounders. Non-parametric bivariate and multivariate statistical tests were performed. Results: Correlations suggested there to generally be a positive relationship between physical activity and quality of life. Multivariate logistic regression analyses controlling for possible confounders showed light physical activity to increase the odds of experiencing well-being, engagement and social anchorage, whereas strenuous physical activity increased the odds of experiencing engagement and emotional support. Thus, light physical activity and strenuous physical activity differed in their relation to quality of life generally. Conclusions: The results indicate that physical activity has a salutogenic effect by enhancing the quality of life, and it can be assumed to be connected to quality of life by generating pleasure and relaxation.

Persons with knee symptoms recognize the health benefits of engaging in physical activity, but uncertainty persists about whether regular strenuous physical activity or exercise can accelerate tissue damage. A sedentary lifestyle of inactivity or underloading may also be associated with deleterious joint health. To establish whether long-term strenuous physical activity participation and extensive sitting behavior are each associated with increased risk of developing radiographic knee osteoarthritis (KOA) in individuals at high risk for the disease. This cohort study analyzed data from the Osteoarthritis Initiative, a prospective longitudinal cohort study of men and women with or at an increased risk of developing symptomatic, radiographic KOA. Community-dwelling adults were recruited from 4 US sites (Baltimore, Maryland; Columbus, Ohio; Pittsburgh, Pennsylvania; and Pawtucket, Rhode Island) and were followed up for up to 10 years. Individuals were included if they had a baseline Kellgren and Lawrence grade of 0 in both knees and completed a PASE (Physical Activity Scale for the Elderly) questionnaire at baseline and at least 2 follow-up visits over an 8-year interval. Data analyses were conducted from May 2018 to November 2018. Baseline to 8-year trajectories of strenuous physical activity participation and extensive sitting behavior were identified using group-based trajectory models. Incident radiographic KOA, defined as Kellgren and Lawrence grade 2 or higher in either knee by the 10-year follow-up visit. A total of 1194 participants were included in the sample (697 women [58.4%]), with a baseline mean (SD) age of 58.4 (8.9) years and mean body mass index (BMI) of 26.8 (4.5). Four distinct trajectories of weekly hours spent in strenuous physical activities and 3 distinct trajectories of extensive sitting were identified. Long-term engagement in low-to-moderate physical activities (adjusted odds ratio [OR], 0.69; 95% CI, 0.48-1.01) or any strenuous physical activities (adjusted OR, 0.75; 95% CI, 0.53-1.07) was not associated with 10-year incident radiographic KOA. Persistent extensive sitting was not associated with incident KOA. Despite relatively mild symptoms and high function in this early-stage sample, 594 participants (49.7%) did not engage in any strenuous physical activities (ie, 0 h/wk) across 8 years, and 507 (42.5%) engaged in persistent moderate-to-high frequency of extensive sitting. Older age, higher BMI, more severe knee pain, non-college graduate educational level, weaker quadriceps, and depression were each associated with a persistent lack of engagement in strenuous physical activities. Results from this study appeared to show no association between long-term strenuous physical activity participation and incident radiographic KOA. The findings raise the possibility of a protective association between incident KOA and a low-to-moderate level of strenuous physical activities.

Existing data suggest that physical activity reduces colon cancer risk, but the association is not consistently observed in women. One potential explanation for this inconsistency is that hormone therapy, which is associated with lower colon cancer risk, acts as a modifier of the physical activity/colon cancer relationship. Participants in the California Teachers Study (N = 120,147), a prospective cohort of female teachers and administrators residing in California, ages 22 to 84 years at baseline and with no prior history of colon cancer were eligible for study. Between 1996 and 2002, 395 patients were diagnosed with invasive colon cancer. The relative risks (RR) associated with lifetime (high school through age 54 years or current age) and recent (past 3 years) strenuous and moderate recreational physical activity were estimated using Cox proportional hazards regression models. Combined lifetime moderate and strenuous recreational physical activity was only modestly associated with colon cancer risk in the cohort [>or=4 versus <or=0.5 h/wk/y: RR, 0.75; 95% confidence interval, 0.57-1.00; P(trend) = 0.23]. Lifetime physical activity reduced colon cancer risk among postmenopausal women who had never taken hormone therapy (>or=4 versus <or=0.5 h/wk/y: RR, 0.51; 95% confidence interval, 0.31-0.85; P(trend) = 0.02). Postmenopausal women with histories of hormone therapy use had lower colon cancer risk, but their risk was not associated with physical activity. The likelihood ratio test for interaction between hormone use and lifetime moderate plus strenuous physical activity was of borderline statistical significance (P = 0.05). We observed no effect modification by age, body mass index, smoking status, menopausal status, or folate intake. Lifetime recreational physical activity may protect against colon cancer among postmenopausal women who have never used hormone therapy. Among hormone therapy users, who have lower risk of colon cancer, recreational physical activity does not seem to provide any additional benefit. With declining rates of hormone therapy use, physical activity offers one possible means for reducing women's colon cancer risk.

Commentary on the paper by Bernaards et al (see page 10) Occupational health professionals and researchers are primarily concerned with examining and preventing the specific health effects of exposures to...

Aims: To investigate the longitudinal relation between strenuous leisure time physical activity and psychological complaints (depression and emotional exhaustion) in a Dutch working population in order to find evidence for...

Trajectories of strenuous physical activity and extensive sitting and 10-year incident radiographic knee OA