Validity of the Bottle Buoyancy Model for Body Fat Determination

International Journal of Exercise Science 10(1): 87-96, 2017. We investigated a modification of the bottle buoyancy (BB) method in comparison to single frequency, bioelectric impedance analysis (BIA) as a valid noninvasive method of percent body fat (%BF) determination. Twenty-eight participants (15 men, 13 women), in counterbalanced-order, completed the BB, BIA, and computerized hydrostatic densitometry (HD) methods. We elected to modify the BB method using a 12.15 L container with participants hugging the container in an upright position. Consistency measures of intraclass correlation coefficient (ICC), typical error (TE), coefficient of variation (CV) and total error of measurement (TEM) are reported. Our modification of the BB resulted in less “bobbing” than described in the previous method, and took ~5 to 15 min per participant to complete. Group values (%BF) did not differ (p \u3e 0.05) for BB (20.7 ± 6.6), BIA (21.0 ± 9.7), and HD (20.2 ± 7.2). Strong measurement agreement was observed between BB and HD (ICC: 0.95, TE: 1.80 %BF, CV: 10.7%, TEM: 1.77 %BF). Agreement between BIA and HD (ICC: 0.85, TE: 3.35 %BF, CV: 19.6%, TEM: 3.29 %BF) was lower than BB. Our modification of the BB method resulted in similar measurement consistency with the originating method. The BB method appears to represent a valid surrogate measure of %BF, superior to that observed with BIA

Influence of Exercise Type on Maternal Blood Pressure Adaptation throughout Pregnancy

BACKGROUND: It has been reported that 10% of all pregnancies are complicated by a hypertensive disorder of pregnancy. Previous research has shown that moderate-vigorous intensity exercise has a positive effect on maternal resting blood pressure. A research gap, however, exists related to how different types of exercise (resistance, aerobic, combined resistance and aerobic) affect maternal blood pressure. Most of the previous studies solely focused on aerobic exercise. OBJECTIVE: The aim of this study was to examine the effects of exercise types on maternal blood pressure throughout pregnancy. STUDY DESIGN: This study employed a secondary analysis using data from a randomized controlled prenatal exercise intervention trial. This study utilized 3 exercise intervention groups (aerobic, resistance, combination) and compared the results with those of a nonexercize control group. Participants completed 3 50-minute sessions weekly from 16 weeks of gestation until delivery. Maternal vital signs and physical measurements such as systolic blood pressure, diastolic blood pressure, and heart rate were measured every 4 weeks throughout the intervention period. Between-group mean differences in maternal measurements were assessed using Pearson's chi-square tests for continuous (age, prepregnancy body mass index, heart rate, systolic blood pressure, diastolic blood pressure, pulse pressure) variables. For gravida, exact Wilcox 2-sample tests were performed to determine between-group differences in mean values. Hierarchical linear growth curves were used to estimate maternal trajectories of systolic blood pressure and diastolic blood pressure from 16 weeks to 36 weeks’ gestation in each of the 4 groups (aerobic, combination, control, and resistance). RESULTS: There were no differences among the groups in maternal age or prepregnancy body mass index. Controlling for maternal body mass index, the lowest significant systolic blood pressure curve was noted throughout the pregnancy for women who participated in resistance exercise, followed by women in the aerobic exercise group all relative to the no exercise control group. At 36 weeks’ gestation, the systolic blood pressure was lower in the resistance group by 12.17 mm Hg (P<.001) and in the aerobic group by 7.90 mm Hg (P<.001) relative to controls. No significant change in systolic blood pressure was noted in the combination group in comparison with controls at 36 weeks’ gestation. Similarly, we demonstrated a significantly lower linear growth curve in diastolic blood pressure that was maintained throughout pregnancy in any exercise type relative to controls. After controlling for maternal body mass index, all 3 exercise types (combination, resistance, and aerobic) significantly predicted a similar decrease in diastolic blood pressure that was maintained throughout pregnancy. At 36 weeks’ gestation, the diastolic blood pressure was lower in the aerobic group by 7.30 mm Hg (P<.01), in the combination group by 6.43 mm Hg (P<.05), and in the resistance group relative to controls. CONCLUSION: Overall, all exercise types were beneficial in lowering maternal resting blood pressure throughout pregnancy. Resistance training was noted to be the most beneficial in improving systolic blood pressure, followed by aerobic exercise. All 3 exercise groups were noted to improve diastolic blood pressure equally. Further research needs to be done to determine if either resistance or aerobic exercise throughout pregnancy decreases the risk for hypertensive disorders of pregnancy and the associated morbidity and mortality

Leisure-Time Physical Activity before and during Pregnancy Is Associated with Improved Insulin Resistance in Late Pregnancy

A total of 83 third trimester pregnant women were recruited to examine the role of pre-pregnancy versus late-pregnancy physical activity on maternal insulin resistance. Principal component analysis plots demonstrated a distinction between the high and low Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) groups. The variation was driven primarily by exercise prior to and during pregnancy. Specifically, higher levels of physical activity prior to pregnancy was associated with a lower HOMA-IR and is not modified by other variables. Women who were active prior to pregnancy were more active during pregnancy. These results suggest that being active before pregnancy may be a good strategy for mitigating the risk of insulin resistance during late pregnancy

RRP 3MT - Developing a New Regression Model to Determine Body Composition to Replace Body Mass Index

Body mass index (BMI) has been used as a measure of body composition of individuals for health risk assessments despite several factors that inhibit the equation’s ability to form a reliable output [1]. Gender, age, ethnicity, activity level, and body morphometrics all uniquely contribute to an individual’s overall body composition and are not accounted for using the standard (kg/m^2) BMI equation. Through the analysis of body anthropometric measures, gender, and activity level, a more valid and reliable representation of body composition can be established using a regression model equation. Expanding on previously established metric measures of the body roundness index (BRI), additional variables may be added to further ensure the validity and reliability of these tests and consequent medical preventions and diagnoses [2]. [1] Blackburn, H., & Jacobs Jr., D. (2014). Commentary: Origins and evolution of body mass index (BMI): continuing saga. International Journal of Epidemiology, 43(3), 665-669. https://doi.org/10.1093/ije/dyu061 [2] Thomas, D. M., Bredlau, C., Bosy-Westphal, A., Mueller, M., Shen, W., Gallagher, D., Maeda, Y., McDougall, A., Peterson, C. M., Ravussin, E., & Heymsfield, S. B. (2013). Relationships between body roundness with body fat and visceral adipose tissue emerging from a new geometrical model. Obesity (Silver Spring, Md.), 21(11), 2264–2271. https://doi.org/10.1002/oby.2040

Self-Reported Intake and Circulating EPA and DHA Concentrations in US Pregnant Women

In the United States, pregnant women have low concentrations of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which are essential for fetal development. Although maternal blood provides accurate polyunsaturated fatty acid (PUFA) concentrations, venipuncture is expensive and not always accessible. PUFA-containing foods consumption, both omega-3 ad omega-6 is supposed to reflect in the status (plasma, RBC, adipose tissue) of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). De novo synthesis of DHA and EPA during pregnancy is supposed to be higher compared to pre and/or post-pregnancy periods. Thus, this study aimed to determine the association between maternal self-reported dietary intake of foods high in DHA and EPA, along with vegetable oils as a source of omega-6 fatty acids, with maternal blood DHA and EPA concentrations. Pregnant women (13–16 weeks gestation) were recruited and asked to complete a food-frequency questionnaire (FFQ) and blood draw at enrollment and 36 weeks. Circulating concentrations of DHA and EPA were quantified and change scores were calculated. Correlations were done to determine associations between FFQ results and EPA/DHA maternal blood concentrations. Regression analyses were run to examine significant predictors of the main outcomes. Overall, PUFA-food consumption and RBC’s DHA levels decreased from early to late pregnancy; self-reported PUFA-rich food consumption positively correlated with DHA and EPA levels. DHA concentration was predicted by self-reported PUFA-rich oils (sunflower/soy/corn/olive) consumption, but EPA concentration was predicted by maternal BMI. These findings suggest that EPA and DHA consumption decreased across pregnancy and the FFQ can be utilized as an effective method for estimating PUFA blood concentration during pregnancy