MVPA is associated with lower weight gain in 8-10 year old children: a prospective study with 1 year follow-up

Background

Studies relating physical activity (PA) to weight gain in children have produced mixed results, although there is some evidence for stronger associations with more intense physical activities. The present study tested the hypothesis that weight gain over one year in 8–10 year olds would be more strongly predicted by moderate and vigorous physical activity (MVPA) than total physical activity (total PA) or sedentary behaviour.

Methodology

Participants were 280 children taking part in the Physical Exercise and Appetite in Children Study (PEACHES). Weight status was assessed using body mass index (BMI), fat mass index (FMI), and waist circumference (WC) in school Year 4 (baseline; age 8.7 yrs) and Year 5 (follow-up; age 9.7 yrs). Physical activity was measured at baseline using the Actigraph GT1M accelerometer to assess total PA (mean accelerometers counts per minute), MVPA; ≥4000 counts per minute) and sedentary time (<100 counts per minute).

Principal Findings

After adjustment for baseline BMI, SES, sex and ethnicity, MVPA was significantly associated with follow–up BMI (adjusted β = −0.07; p = 0.002). This association was independent of total PA or sedentary time. Similar results were observed for FMI; again MVPA was significantly associated with follow up FMI (β = −0.16; p = 0.001) independent of total PA or sedentary time. The pattern was similar for WC (β = −0.07), but the association between MVPA and WC did not reach significance at p = 0.06.

Conclusion

The results of this study strongly support promotion of MVPA in children.     

Correlates of reported and recorded time spent in physical activity in working adults: results from the commuting and health in cambridge study

Background

The correlates of physical activity in adults are relatively well studied. However, many studies use self-reported (‘reported’) measures of activity and we know little about the possible differences between the correlates of reported and objective (‘recorded’) measures of physical activity. We compared the correlates of reported and recorded time spent in moderate-to-vigorous physical activity (MVPA) in a sample of working adults.

Methods

In 2009, participants in the Commuting and Health in Cambridge study completed questionnaires assessing individual, socio-demographic, health and contextual characteristics. Recorded time spent in MVPA over seven days was ascertained using accelerometers and reported time spent in MVPA was assessed using the Recent Physical Activity Questionnaire (RPAQ). Correlates of MVPA were investigated using sex-specific linear regression models.

Results

486 participants (70% women) provided both reported and recorded physical activity data. 89% recorded at least 30 minutes of MVPA per day. In men, none of the potential explanatory variables were associated with both reported and recorded time spent in MVPA. In women, of all the potential explanatory variables only that of having a standing or manual occupation was associated with both reported (+42 min/day; 95% CI 16.4 to 68.4, p = 0.001) and recorded (+9 min/day; 95% CI: 3.5 to 15.7, p = 0.002) time spent in MVPA.

Discussion

The use of an objective measure of physical activity may influence the correlates which are observed. Researchers may wish to consider using and analysing recorded and reported measures in combination to gain a more complete view of the correlates of physical activity.     

Population-Referenced Percentiles for Waist-Worn Accelerometer-Derived Total Activity Counts in U.S. Youth: 2003 – 2006 NHANES

Background

The total activity volume performed is an overall measure that takes into account the frequency, intensity, and duration of activities performed. The importance of considering total activity volume is shown by recent studies indicating that light physical activity (LPA) and intermittent moderate-to-vigorous physical activity (MVPA) have health benefits. Accelerometer-derived total activity counts (TAC) per day from a waist-worn accelerometer can serve as a proxy for an individual''s total activity volume. The purpose of this study was to develop age- and gender-specific percentiles for daily TAC, minutes of MVPA, and minutes of LPA in U.S. youth ages 6 – 19 y.

Methods

Data from the 2003 – 2006 NHANES waist-worn accelerometer component were used in this analysis. The sample was composed of youth aged 6 – 19 years with at least 4 d of ≥ 10 hours of accelerometer wear time (N = 3698). MVPA was defined using age specific cutpoints as the total number of minutes at ≥4 metabolic equivalents (METs) for youth 6 – 17 y or minutes with ≥2020 counts for youth 18 – 19 y. LPA was defined as the total number of minutes between 100 counts and the MVPA threshold. TAC/d, MVPA, and LPA were averaged across all valid days.

Results

For males in the 50^th percentile, the median activity level was 441,431 TAC/d, with 53 min/d of MVPA and 368 min/d of LPA. The median level of activity for females was 234,322 TAC/d, with 32 min/d of MVPA and 355 min/d of LPA.

Conclusion

Population referenced TAC/d percentiles for U.S. youth ages 6-19 y provide a novel means of characterizing the total activity volume performed by children and adolescents.     

A short-term physical activity randomized trial in the Lower Mississippi Delta

Background

The purpose of this study was to determine if a short-term pedometer-based intervention results in immediate increases in time spent in moderate-to-vigorous physical activity (MVPA) compared to a minimal educational intervention.

Methods

A sample of 43 overweight adults 35 to 64 years of age participated in a one week pedometer-based feasibility trial monitored by accelerometry. Participants were randomized into a one-week education-only group or a group that also wore a pedometer. Accelerometer-measured MVPA was measured over 7 days at baseline and again for 7 days immediately post-intervention.

Results

Minutes of MVPA increased significantly in the overall sample (p = 0.02); however, the effect of adding the pedometer to the education program was not significant (p = 0.89). Mean (±SE) MVPA increased from 12.7±2.4 min/day to 16.2±3.6 min/day in the education-only group and from 13.2±3.3 min/day to 16.3±3.9 min/day in the education+pedometer group. The correlation between change in steps/day and change in MVPA was 0.69 (p<0.0001).

Conclusions

The results of this study suggest that the addition of a pedometer to a short-term education program does not produce added benefits with respect to increasing physical activity in the Lower Mississippi Delta.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01264757","term_id":"NCT01264757"}}NCT01264757     

Does the Fractionalization of Daily Physical Activity (Sporadic vs. Bouts) Impact Cardiometabolic Risk Factors in Children and Youth?

Objective

Children and youth accumulate their daily moderate-to-vigorous physical activity (MVPA) in bouts (i.e., ≥5 consecutive minutes) and in a sporadic manner (i.e., <5 consecutive minutes). The study objective was to determine, within children and youth, whether MVPA accumulated in bouts is more strongly associated with cardiometabolic risk factors than an equivalent volume of MVPA accumulated sporadically.

Methods

Participants consisted of 2754 children and youth aged 6–19 years from the 2003–2006 National Health and Nutrition Examination Survey, a representative cross-sectional study. Bouts and sporadic MVPA were measured objectively over 7 days using Actigraph accelerometers. Thresholds of 5 and 10 consecutive minutes were used to differentiate between bouts and sporadic MVPA. A high cardiometabolic risk factor score (CRS) was created based on measures of waist circumference, non-high-density lipoprotein cholesterol, C-reactive protein, and systolic blood pressure. Associations were examined using logistic regression and controlled for covariates (sex, age, ethnicity, socioeconomic status, dietary fat and sodium, smoking, and accelerometry wear time).

Results

The odds of a high CRS decreased in a dose-response for both the sporadic and bout MVPA measures. Relative to quartile 1, the odds ratio (95% confidence interval) for a high CRS in quartile 4 was 0.25 (0.10–0.60) for sporadic MVPA, 0.17 (0.09–0.34) for ≥5 minute bouts of MVPA, and 0.19 (0.11–0.34) for ≥10 minute bouts of MVPA. The sporadic and bout MVPA measures had a similar ability to distinguish between participants with high and normal CRS. Relative to 0 minutes of MVPA, an equivalent number of minutes of sporadic MVPA and bouts of MVPA had an almost identical odds ratio for a high CRS. The findings were consistent for 5 and 10 minute bout thresholds.

Conclusions

The relations between sporadic MVPA and bouts of MVPA with cardiometabolic risk factors were remarkably similar in children and youth.     

Serum fetuin-A associates with type 2 diabetes and insulin resistance in Chinese adults

Background

Previous studies have demonstrated that fetuin-A is related to insulin resistance among subjects with normal glucose tolerance but not patients with type 2 diabetes. There are limited data available concerning fetuin-A and insulin resistance in Chinese. We aimed to study the association of feuin-A with insulin resistance among participants with or without type 2 diabetes in a large sample size of adults aged 40 and older.

Methodology and Principal Findings

A community-based cross-sectional study was performed among 5,227 Chinese adults. The average age of our study was 61.5±9.9 years. Serum fetuin-A concentrations were not significantly different between male and female (296.9 vs. 292.9 mg/l, p = 0.11). Compared with the lowest quartile, the highest quartile of serum fetuin-A revealed a significant higher proportion of type 2 diabetic patients (34.8% vs. 27.3%, p<0.0001). In the multinomial logit models, the risk of type 2 diabetes was associated with each one quartile increase of serum fetuin-A concentrations when referenced not only to normal glucose tolerance (OR 1.24, 95% CI 1.07–1.43, p = 0.004) but also to impaired glucose regulation (OR 1.25, 95% CI 1.08–1.44, p = 0.003, respectively), after adjustment for age, sex, community, current smoking, and current drinking. The logistic regression analysis showed that fetuin-A were associated with elevated HOMA-IR and fasting serum insulin both among the participants with or without type 2 diabetes in the full adjusted analysis. There was no significant association between elevated serum fetuin-A concentrations and impaired glucose regulation (all p≥0.12).

Conclusions and Significance

Higher fetuin-A concentrations were associated with type 2 diabetes and insulin resistance in middle aged and elderly Chinese.     

Serum carcinoembryonic antigen is associated with abdominal visceral fat accumulation in female korean nonsmokers

Background

Carcinoembryonic antigen (CEA) is a tumor marker overexpressed in adenocarcinoma that has proinflammatory properties. Recent studies have reported that CEA is positively associated with carotid atherosclerosis and metabolic syndrome. Because visceral obesity is a known risk factor for cardiometabolic diseases, CEA may also be associated with visceral adiposity. Therefore, we investigated the relationship between serum CEA concentration and visceral obesity in female Korean nonsmokers.

Methods

A total of 270 Korean female nonsmokers were enrolled during their routine health check-ups. Biomarkers of metabolic risk factors were assessed along with body composition by computed tomography. Serum CEA levels were measured by using a chemiluminescence immunoassay analyzer.

Results

Serum CEA levels correlated with visceral fat area, fasting glucose, and triglyceride levels after adjusting for age and BMI. The mean visceral fat area increased significantly with the increasing CEA tirtiles. In a step-wise multiple regression analysis, age (β = 0.26, p<0.01) and visceral fat area (β = 0.19, p = 0.03) were identified as explanatory variables for serum CEA level.

Conclusions

This study suggested that CEA may be a mediator that links metabolic disturbance and tumorigenesis in visceral obesity. Further studies are required to better understand the clinical and pathophysiological significance of our findings.     

Physical fitness and telomere length in patients with coronary heart disease: findings from the Heart and Soul Study

Background

Short telomere length (TL) is an independent predictor of mortality in patients with coronary heart disease (CHD). However, the relationship between physical fitness and TL has not been explored in these patients.

Methods

In a cross sectional study of 944 outpatients with stable CHD, we performed exercise treadmill testing, assessed self-reported physical activity, and measured leukocyte TL using a quantitative PCR assay. We used generalized linear models to calculate mean TL (T/S ratio), and logistic regression models to compare the proportion of patients with short TL (defined as the lowest quartile), among participants with low, medium and high physical fitness, based on metabolic equivalent tasks achieved (METs).

Results

229 participants had low physical fitness (<5 METS), 334 had moderate physical fitness (5–7 METS), and 381 had high physical fitness (>7 METS). Mean ± T/S ratio ranged from 0.86±0.21 (5349±3781 base pairs) in those with low physical fitness to 0.95±0.23 (5566±3829 base pairs) in those with high physical fitness (p<.001). This association remained strong after adjustment for numerous patient characteristics, including measures of cardiac disease severity and physical inactivity (p = 0.005). Compared with participants with high physical fitness, those with low physical fitness had 2-fold greater odds of having TL in the lowest quartile (OR 2.39, 95% CI 1.60–3.55; p<.001). This association was similar after multivariable adjustment (OR 1.94, 95%CI, 1.18–3.20; p = 0.009). Self-reported physical inactivity was associated with shorter TL in unadjusted analyses, but not after multivariable adjustment.

Conclusions

We found that worse objectively-assessed physical fitness is associated with shorter leukocyte telomere length in patients with CHD. The clinical implications of this association deserve further study.     

Light-Intensity Physical Activity and Cardiometabolic Biomarkers in US Adolescents

Background

The minimal physical activity intensity that would confer health benefits among adolescents is unknown. The purpose of this study was to examine the associations of accelerometer-derived light-intensity (split into low and high) physical activity, and moderate- to vigorous-intensity physical activity with cardiometabolic biomarkers in a large population-based sample.

Methods

The study is based on 1,731 adolescents, aged 12–19 years from the 2003/04 and 2005/06 National Health and Nutrition Examination Survey. Low light-intensity activity (100–799 counts/min), high light-intensity activity (800 counts/min to <4 METs) and moderate- to vigorous-intensity activity (≥4 METs, Freedson age-specific equation) were accelerometer-derived. Cardiometabolic biomarkers, including waist circumference, systolic blood pressure, diastolic blood pressure, HDL-cholesterol, and C-reactive protein were measured. Triglycerides, LDL- cholesterol, insulin, glucose, and homeostatic model assessments of β-cell function (HOMA-%B) and insulin sensitivity (HOMA-%S) were also measured in a fasting sub-sample (n = 807).

Results

Adjusted for confounders, each additional hour/day of low light-intensity activity was associated with 0.59 (95% CI: 1.18–0.01) mmHG lower diastolic blood pressure. Each additional hour/day of high light-intensity activity was associated with 1.67 (2.94–0.39) mmHG lower diastolic blood pressure and 0.04 (0.001–0.07) mmol/L higher HDL-cholesterol. Each additional hour/day of moderate- to vigorous-intensity activity was associated with 3.54 (5.73–1.35) mmHG lower systolic blood pressure, 5.49 (1.11–9.77)% lower waist circumference, 25.87 (6.08–49.34)% lower insulin, and 16.18 (4.92–28.53)% higher HOMA-%S.

Conclusions

Time spent in low light-intensity physical activity and high light-intensity physical activity had some favorable associations with biomarkers. Consistent with current physical activity recommendations for adolescents, moderate- to vigorous-intensity activity had favorable associations with many cardiometabolic biomarkers. While increasing MVPA should still be a public health priority, further studies are needed to identify dose-response relationships for light-intensity activity thresholds to inform future recommendations and interventions for adolescents.     

The 24-h energy intake of obese adolescents is spontaneously reduced after intensive exercise: a randomized controlled trial in calorimetric chambers

Background

Physical exercise can modify subsequent energy intake and appetite and may thus be of particular interest in terms of obesity treatment. However, it is still unclear whether an intensive bout of exercise can affect the energy consumption of obese children and adolescents.

Objective

To compare the impact of high vs. moderate intensity exercises on subsequent 24-h energy intake, macronutrient preferences, appetite sensations, energy expenditure and balance in obese adolescent.

Design

This randomized cross-over trial involves 15 obese adolescent boys who were asked to randomly complete three 24-h sessions in a metabolic chamber, each separated by at least 7 days: (1) sedentary (SED); (2) Low-Intensity Exercise (LIE) (40% maximal oxygen uptake, VO₂max); (3) High-Intensity Exercise (HIE) (75%VO₂max).

Results

Despite unchanged appetite sensations, 24-h total energy intake following HIE was 6–11% lower compared to LIE and SED (p<0.05), whereas no differences appeared between SED and LIE. Energy intake at lunch was 9.4% and 8.4% lower after HIE compared to SED and LIE, respectively (p<0.05). At dinner time, it was 20.5% and 19.7% lower after HIE compared to SED and LIE, respectively (p<0.01). 24-h energy expenditure was not significantly altered. Thus, the 24-h energy balance was significantly reduced during HIE compared to SED and LIE (p<0.01), whereas those of SED and LIE did not differ.

Conclusions

In obese adolescent boys, HIE has a beneficial impact on 24-h energy balance, mainly due to the spontaneous decrease in energy intake during lunch and dinner following the exercise bout. Prescribing high-intensity exercises to promote weight loss may therefore provide effective results without affecting appetite sensations and, as a result, food frustrations.

Trial Registration

ClinicalTrial.gov {"type":"clinical-trial","attrs":{"text":"NCT01036360","term_id":"NCT01036360"}}NCT01036360     

Cardiometabolic risk in US Army recruits and the effects of basic combat training

Background

Cardiometabolic disease risk in US military recruits and the effects of military training have not been determined. This study examined lifestyle factors and biomarkers associated with cardiometabolic risk in US Army recruits (209; 118 male, 91 female, 23±5 yr) before, during, and after basic combat training (BCT).

Methodology/Principal Findings

Anthropometrics; fasting total (TC), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol; triglycerides (TG); glucose; and insulin were measured at baseline and every 3 wks during the 10 wk BCT course. At baseline, 14% of recruits were obese (BMI>30 kg/m²), 27% were cigarette smokers, 37% were sedentary, and 34% reported a family history of cardiometabolic disease. TC was above recommended levels in 8%, LDL in 39%, TG in 5%, and glucose in 8% of recruits, and HDL was below recommended levels in 33% of recruits at baseline. By week 9, TC decreased 8%, LDL 10%, TG 13%, glucose 6% and homeostasis model assessment of insulin resistance (HOMA-IR) 40% in men (P<0.05). In women, TC, LDL, glucose and HOMA-IR were decreased from baseline at weeks 3 and 6 (P<0.05), but were not different from baseline levels at week 9. During BCT, body weight declined in men but not women, while body fat percentage declined in both men and women (P<0.05).

Conclusions/Significance

At the start of military service, the prevalence of cardiometabolic risk in US military recruits is comparable to that reported in similar, college-aged populations. Military training appears to be an effective strategy that may mitigate risk in young people through improvements in lipid profiles and glycemic control.     

Circulating matrix metalloproteinase-9 is associated with cardiovascular risk factors in a middle-aged normal population

Background

Elevated levels of circulating matrix metalloproteinase-9 (MMP-9) have been demonstrated in patients with established coronary artery disease (CAD). The aim of this study was to analyse levels of MMP-9 in a population free from symptomatic CAD and investigate their associations with cardiovascular (CV) risk factors, including C-reactive protein (CRP).

Methods

A cross-sectional study was performed in a population based random sample aged 45–69 (n = 345, 50% women). MMP-9 levels were measured in EDTA-plasma using an ELISA-method. CV risk factors were measured using questionnaires and standard laboratory methods.

Results

Plasma MMP-9 was detectable in all participants, mean 38.9 ng/mL (SD 22.1 ng/mL). Among individuals without reported symptomatic CAD a positive association (p<0.001) was seen, for both men and women, of MMP-9 levels regarding total risk load of eight CV risk factors i.e. blood pressure, dyslipidemia, diabetes, obesity, smoking, alcohol intake, physical activity and fruit and vegetable intake. The association was significant also after adjustment for CRP, and was not driven by a single risk factor alone. In regression models adjusted for age, sex, smoking, alcohol intake and CRP, elevated MMP-9 levels were independently positively associated with systolic blood pressure (p = 0.037), smoking (p<0.001), alcohol intake (p = 0.003) and CRP (p<0.001). The correlation coefficient between MMP-9 and CRP was r = 0.24 (p<0.001).

Conclusions

In a population without reported symptomatic CAD, MMP-9 levels were associated with total CV risk load as well as with single risk factors. This was found also after adjustment for CRP.     

Risk factors associated with increased mortality among HIV infected children initiating antiretroviral therapy (ART) in South Africa

Objective

To identify demographic and clinical risk factors associated with mortality after initiation of antiretroviral therapy (ART) in a cohort of human immunodeficiency (HIV) infected children in KwaZulu-Natal, South Africa.

Methods

We performed a retrospective cohort study of 537 children initiating antiretroviral therapy at McCord Hospital in KwaZulu-Natal, South Africa. Data were extracted from electronic medical records and risk factors associated with mortality were assessed using Cox regression analysis.

Results

Overall there were 47 deaths from the cohort of 537 children initiating ART with over 991 child-years of follow-up (median 22 months on ART), yielding a mortality rate of 4.7 deaths per 100 child years on ART. Univariate analysis indicated that mortality was significantly associated with lower weight-for-age Z-score (p<0.0001), chronic diarrhea (p = 0.0002), lower hemoglobin (p = 0.002), age <3 years (p = 0.003), and CD4% <10% (p = 0.005). The final multivariable Cox proportional hazards mortality model found age less than 3 years (p = 0.004), CD4 <10% (p = 0.01), chronic diarrhea (p = 0.03), weight-for-age Z-score (<0.0001) and female gender as a covariate varying with time (p = 0.03) all significantly associated with mortality.

Conclusion

In addition to recognized risk factors such as young age and advanced immunosuppression, we found female gender to be significantly associated with mortality in this pediatric ART cohort. Future studies are needed to determine whether intrinsic biologic differences or socio-cultural factors place female children with HIV at increased risk of death following initiation of ART.     

CTX (Crosslaps) Rather than Osteopontin Is Associated with Disturbed Glucose Metabolism in Gestational Diabetes

Objective

Reciprocal interaction between bone and glucose metabolism might play a pivotal role in the development of type 2 diabetes. We recently demonstrated that osteocalcin is increased in women with gestational diabetes (GDM) compared to healthy pregnant women and related to enhanced insulin secretion. Here, we aimed to investigate the role of the bone resorption marker CTX and osteopontin (OPN), a key molecule in subclinical inflammation underlying insulin resistance, in gestational diabetes.

Methods

Insulin sensitivity and secretion (derived from OGTT) as well as CTX and osteopontin were investigated in 26 GDM and 52 women with normal glucose tolerance during pregnancy [CON] between 24th and 28th gestational weeks; 24 women also underwent postpartum examination.

Results

CTX was significantly higher in GDM compared to CON (0.44±0.20 vs.0.28±0.12 ng/ml, p<.0001) and positively correlated with osteocalcin (R = 0.64, p<.0001) and parameters of insulin secretion. Osteopontin plasma concentrations were decreased in GDM compared to CON (28.81±22.12 vs.37.68±19.63 ng/ml, p = 0.04), and did not show any relation to insulin secretion or sensitivity, but were significantly correlated with CRP (R = 0.3, p<0.007) and liver enzymes. Twelve weeks after delivery CTX and OPN were increased compared to pregnancy (both p<.0001) and did not differ between GDM and CON.

Conclusion

Our findings support the idea of a tight regulation between bone and glucose metabolism, and suggest, that less curbed CTX during pregnancy might be involved in osteocalcin-mediated amelioration of insulin secretion in GDM. On the other hand, osteopontin was unrelated to insulin resistance in GDM, but associated with inflammatory markers and liver enzymes in all women.     

The effect of exercise training modality on serum brain derived neurotrophic factor levels in individuals with type 2 diabetes

Introduction

Brain derived neurotrophic factor (BDNF) has been implicated in memory, learning, and neurodegenerative diseases. However, the relationship of BDNF with cardiometabolic risk factors is unclear, and the effect of exercise training on BDNF has not been previously explored in individuals with type 2 diabetes.

Methods

Men and women (N = 150) with type 2 diabetes were randomized to an aerobic exercise (aerobic), resistance exercise (resistance), or a combination of both (combination) for 9 months. Serum BDNF levels were evaluated at baseline and follow-up from archived blood samples.

Results

Baseline serum BDNF was not associated with fitness, body composition, anthropometry, glucose control, or strength measures (all, p>0.05). Similarly, no significant change in serum BDNF levels was observed following exercise training in the aerobic (−1649.4 pg/ml, CI: −4768.9 to 1470.2), resistance (−2351.2 pg/ml, CI:−5290.7 to 588.3), or combination groups (−827.4 pg/ml, CI: −3533.3 to1878.5) compared to the control group (−2320.0 pg/ml, CI: −5750.8 to 1110.8). However, reductions in waist circumference were directly associated with changes in serum BDNF following training (r = 0.25, p = 0.005).

Conclusions

Serum BDNF was not associated with fitness, body composition, anthropometry, glucose control, or strength measures at baseline. Likewise, serum BDNF measures were not altered by 9 months of aerobic, resistance, or combination training. However, reductions in waist circumference were associated with decreased serum BDNF levels. Future studies should investigate the relevance of BDNF with measures of cognitive function specifically in individuals with type-2 diabetes.     

The effect of prolonged physical activity performed during extreme caloric deprivation on cardiac function

Background

Endurance exercise may induce transient cardiac dysfunction. Data regarding the effect of caloric restriction on cardiac function is limited. We studied the effect of physical activity performed during extreme caloric deprivation on cardiac function.

Methods

Thirty-nine healthy male soldiers (mean age 20±0.3 years) were studied during a field training exercise lasted 85–103 hours, with negligible food intake and unlimited water supply. Anthropometric measurements, echocardiographic examinations and blood and urine tests were performed before and after the training exercise.

Results

Baseline VO₂ max was 59±5.5 ml/kg/min. Participants'' mean weight reduction was 5.7±0.9 kg. There was an increase in plasma urea (11.6±2.6 to 15.8±3.8 mmol/L, p<0.001) and urine osmolarity (692±212 to 1094±140 mmol/kg, p<0.001) and a decrease in sodium levels (140.5±1.0 to 136.6±2.1 mmol/L, p<0.001) at the end of the study. Significant alterations in diastolic parameters included a decrease in mitral E wave (93.6 to 83.5 cm/s; p = 0.003), without change in E/A and E/E′ ratios, and an increase in iso-volumic relaxation time (73.9 to 82.9 ms, p = 0.006). There was no change in left or right ventricular systolic function, or pulmonary arterial pressure. Brain natriuretic peptide (BNP) levels were significantly reduced post-training (median 9 to 0 pg/ml, p<0.001). There was no elevation in Troponin T or CRP levels. On multivariate analysis, BNP reduction correlated with sodium levels and weight reduction (R = 0.8, p<0.001).

Conclusions

Exposure to prolonged physical activity performed under caloric deprivation resulted in minor alterations of left ventricular diastolic function. BNP levels were significantly reduced due to negative water and sodium balance.     

Maternal perception of reduced fetal movements is associated with altered placental structure and function

Background

Maternal perception of reduced fetal movement (RFM) is associated with increased risk of stillbirth and fetal growth restriction (FGR). DFM is thought to represent fetal compensation to conserve energy due to insufficient oxygen and nutrient transfer resulting from placental insufficiency. To date there have been no studies of placental structure in cases of DFM.

Objective

To determine whether maternal perception of reduced fetal movements (RFM) is associated with abnormalities in placental structure and function.

Design

Placentas were collected from women with RFM after 28 weeks gestation if delivery occurred within 1 week. Women with normal movements served as a control group. Placentas were weighed and photographs taken. Microscopic structure was evaluated by immunohistochemical staining and image analysis. System A amino acid transporter activity was measured as a marker of placental function.Placentas from all pregnancies with RFM (irrespective of outcome) had greater area with signs of infarction (3.5% vs. 0.6%; p<0.01), a higher density of syncytial knots (p<0.001) and greater proliferation index (p<0.01). Villous vascularity (p<0.001), trophoblast area (p<0.01) and system A activity (p<0.01) were decreased in placentas from RFM compared to controls irrespective of outcome of pregnancy.

Conclusions

This study provides evidence of abnormal placental morphology and function in women with RFM and supports the proposition of a causal association between placental insufficiency and RFM. This suggests that women presenting with RFM require further investigation to identify those with placental insufficiency.     

Satiating capacity and post-prandial relationships between appetite parameters and gut-peptide concentrations with solid and liquefied carbohydrate

Background

Differences in satiating capacity of liquid and solid meals are unclear.

Objective

Investigating appetite parameters, physiological measurements and within-subject relationships after consumption of a single macronutrient, subject-specific carbohydrate meal in liquefied versus solid form, controlled for energy density, weight and volume.

Design

In a cross-over design, ten male subjects (age = 21.1±3.9 y, BMI = 22.4±1.2 kg/m²) consumed a solid (CS, whole peaches +750 ml water) and liquefied carbohydrate (CL, peach blended in 500 ml water +250 ml water) lunch. Appetite profiles, insulin-, glucose- and ghrelin concentrations were measured over three hours. Post-prandial relationships between appetite and blood parameters were calculated using subject-specific regression analyses.

Results

Fullness ratings were higher in the CL (85±5 mm) compared to the CS condition (73±8 mm) at 20 min (p<0.03). Glucose concentrations peaked 20 to 30 min after the start of the lunch in the CL condition, and 30 to 40 min after start of the CS condition. Correspondingly, insulin concentrations were peaked at 20–30 min in the CL condition, and at 30–40 min in the CS condition. AUC or condition x time interactions were not different comparing the CL and the CS condition. Insulin was significantly higher in the CS compared to the CL condition 40 min after the start of the lunch (p<0.05). Fullness scores were significantly related to insulin concentrations but not to glucose concentrations; desire to eat scores were significantly associated with ghrelin concentrations in both, the CL and the CS condition. The relationship between fullness scores and glucose concentrations was not statistically significant.

Conclusion

Liquefied and solid carbohydrate meals do not differ in satiating capacity, supported by appetite profile and relevant blood parameters. Postprandially, fullness and desire to eat were associated with respectively insulin and ghrelin concentrations.     

Skeletal muscle phosphodiester content relates to body mass and glycemic control

Background

Aging and insulin resistance have been related to reduced mitochondrial function and oxidative stress. Muscular phosphodiesters (PDE) are comprised of metabolites of phospholipid breakdown and may reflect membrane damage. We aimed to test the hypothesis that myocellular PDE are increased in patients with type 2 diabetes (T2D) and correlate inversely with mitochondrial ATP turnover.

Methods

A Cross-sectional study in the Clinical Research Facility of an University hospital was performed. 10 nonobese middle-aged patients with T2D, 10 healthy humans matched for sex, age and physical activity index (CONm) and 18 young healthy humans (CONy) were included. Myocellular PDE and unidirectional flux through ATP synthase (fATP) were measured with ³¹P magnetic resonance spectroscopy (MRS). Intramyocellular (IMCL) and hepatocellular lipid deposition (HCL) were quantified with ¹H MRS. Insulin sensitivity (Rd) was assessed from hyperinsulinemic-euglycemic clamp tests in 10 T2D, 10 CONm and 11 CONy.

Results

During fasting, T2D and CONm had 1.5 fold greater PDE than CONy (2.8±0.2, 2.5±0.2, 1.7±0.1 mmol/l, P = 0.004). Stimulation by insulin did not affect PDE in any group. PDE correlated negatively with Rd (r = −0.552, p<0.005) and fATP (r = −0.396, p<0.05) and positively with age (r = 0.656, p<0.001) and body mass (r = 0.597, p<0.001). PDE also related positively to HbA1c (r = 0.674, p<0.001) and fasting plasma glucose (r = 0.629, p<0.001) within T2D and across all participants.

Conclusions

Muscular PDE concentrations associate with age, lower resting mitochondrial activity and insulin resistance, which is determined mainly by body mass and glycemia.