Women in rural settings are at increased risk for adverse pregnancy outcomes. One potential way to improve pregnancy outcomes in rural settings is through physical activity promotion. However, given the disparities in prenatal care, women in rural areas may not receive information from their health care provider regarding physical activity during pregnancy. Therefore, the purpose of this study was to examine patient and provider communication in a rural setting (both patients' and providers' perspectives) regarding physical activity during pregnancy. A mixed methods study was performed among patients and providers in an obstetrical practice in a rural setting. During early pregnancy, patients were asked questions about their current physical activity levels and intentions for physical activity during their pregnancy. During late pregnancy, patients completed a survey regarding communication from their obstetric provider about exercise during pregnancy. Providers responsible for the patients' prenatal care were surveyed regarding communication with patients about physical activity. Seventy-one pregnant women and five providers participated. 58.2% of patients reported their provider did not discuss physical activity during pregnancy with them at all. Meanwhile, all providers (100%) reported discussing physical activity with all of their patients. Similarly, only 21.8% of patients reported their provider discussed the benefits of exercise during pregnancy, while 100% of providers reported telling their patients about the benefits of exercise during pregnancy. Our study suggests ineffective patient-provider communication regarding physical activity during pregnancy in a rural setting. Improved communication strategies could reduce disparities in health outcomes among pregnant women in rural settings.
PURPOSE: Physical activity (PA) has been shown to be effective for lowering insulin resistance and blood lipid profiles during pregnancy. Recent evidence indicates sedentary time is also associated with poor pregnancy outcomes. The purpose of this study was to determine the relationships between sedentary time and moderate PA, assessed during late pregnancy, and insulin resistance (HOMA-IR) and triglycerides in fasting and postprandial conditions. Postprandial conditions are important to study as humans spend the majority of their time in a fed-state. METHODS: Healthy pregnant women (N=61, 32-36 weeks gestation) were recruited for this study. Sedentary time and moderate intensity PA were objectively assessed using a wrist-worn Actigraph GT9X Link Accelerometer. The device was worn 24 hrs/day for 7 days. Fasting blood lipids, insulin, and glucose were assessed. A standardized high-fat breakfast was consumed and these measures were collected again 120-minutes post-meal (postprandial). All relationships were analyzed with Pearson Product Moment Correlation Coefficients while controlling for pre-pregnancy BMI. RESULTS: Sedentary time was positively correlated with fasting and postprandial insulin resistance (fasting HOMA-IR: r=0.471, p=0.001; postprandial HOMA-IR: r=0.433, p=0.002), while these measures were negatively correlated with light PA (fasting HOMA-IR:-0.395, p=0.005; postprandial HOMA-IR: r=-0.364, p=0.010) and moderate PA (fasting HOMA-IR: r=-0.520, p<0.001; postprandial HOMA-IR: r=-0.477, p=0.001). Sedentary time was positively correlated with fasting triglycerides (r=0.296, p=0.039). Moderate PA was negatively correlated with fasting triglycerides (r=-0.403, p=0.004) and postprandial triglycerides (r=-0.343, p=0.016). CONCLUSIONS: Decreasing sedentary time and adding any intensity PA may positively impact metabolic health during pregnancy by reducing fasting and postprandial insulin resistance, as well as reducing fasting and postprandial triglycerides. This is important as, during pregnancy, insulin resistance is associated with poor pregnancy and neonatal outcomes and increased triglycerides are associated with increased risk of preeclampsia, pre-term birth, and increased maternal cardiovascular risk later in life. NIH NIGMS IDeA Grant 5P20GM103436
PURPOSE: Assessing cardiorespiratory fitness is important for determining health status and prescribing exercise. Measurement of peak oxygen uptake (VO2max) is the gold standard for the evaluation of cardiorespiratory fitness. However, VO2max testing is not always feasible as it involves trained personnel, expensive equipment, and the ability of the test-subject to safely exercise until exhaustion. The ability to accurately predict VO2max using submaximal protocols is important, particularly in special populations such as pregnant women. A validated test to predict fitness levels in pregnant women will allow health care providers to evaluate their patients’ health status as well as tailor their patients’ exercise prescriptions; thus, maximizing the established benefits of exercise during pregnancy. The 6-minute walk test (6MWT) and the YMCA submaximal cycle test (YMCAT) are currently validated tests to predict VO2max in non-gravid populations; however, neither test has been validated during pregnancy. Therefore, the purpose of this study is to determine the validity of the 6MWT and the YMCAT as predictors of cardiorespiratory fitness in healthy weight women during mid-pregnancy. METHODS: Women (18-24 weeks gestation) with low-risk pregnancies participated. At Visit 1, participants completed the 6MWT and the YMCAT in randomized order. Both tests were used to predict VO2max according to validated protocols/equations for non-gravid populations. At Visit 2, participants completed a graded exercise treadmill test (VO2max) using the Bruce Protocol. The predicted VO2max from each submaximal test and the measured VO2max were compared using Pearson Product Moment Correlation Coefficients. RESULTS: 16 women participated in the study (pre-pregnancy BMI= 23.8±4.3 kg/m2, Age=30.1±3.2 yr, Gestation age=22.0±1.3 wk). Mean predicted VO2max values were 36.3±3.9 and 41.1±19.0 ml/kg/min for the 6MWT and the YMCAT, respectively. Mean VO2max obtained from the graded exercise test was 34.9±10.0 ml/kg/min. Actual and predicted VO2max values were not correlated for either submaximal test (6MWT: r=0.28, p=0.31; YMCAT: r=0.08, p=0.79). CONCLUSIONS: The 6MWT and YMCAT do not accurately predict VO2max values during mid-pregnancy. These tests should not be used to estimate peak fitness levels among pregnant women.
Background: Metabolic dysfunction after pregnancy may have serious consequences for a new mother. The purpose of the study was to characterize basic changes that occur in metabolic profiles from late pregnancy through 4– 6 months postpartum. A secondary purpose was to determine metabolic factors that may be contributing to postpartum weight retention. Methods: Participants (n=25) came in for 2 visits: late pregnancy (∼ 34 weeks gestation) and postpartum (4-6 months). Resting metabolic rate (RMR), respiratory quotient (RQ), and substrate oxidation values were assessed for 15 minutes during fasted conditions. Blood was drawn and skinfold anthropometry was performed to assess additional outcomes (inflammation, insulin resistance, lipid profiles, body composition). The participants completed a number of surveys that examined other lifestyle and demographic data of interest. At the postpartum visit, additional assessments regarding sleep and breastfeeding habits were administered. Results: RMR was lower during postpartum (1517.2± 225.1 kcal/day) compared to pregnancy (1867.9± 302.6 kcal/day) (p< 0.001), and remained lower when expressing RMR per kg body weight (postpartum: 22.3± 2.7 vs pregnant: 23.7± 3.4 kcal/kg, (p=0.034). Relative RMR (RMR per kg body weight) was negatively correlated to insulin resistance (HOMA-IR) during postpartum (r=− .463, p=0.034). Maternal HOMA-IR, inflammation (CRP), triglycerides (TAG), and carbohydrate oxidation were all positively correlated to postpartum weight retention (HOMA-IR: r=0.617, p=0.004; CRP: r=0.477, p=0.039, TAG: r=0.463, p=0.040; Carbohydrate Oxidation: (r=0.469, p=0.018). Conclusion: Metabolic rate is lower during postpartum compared to pregnancy, and may be connected to insulin resistance. Maternal insulin resistance, inflammation, blood lipids, and substrate metabolism are all related to postpartum weight retention. Keywords: postnatal, metabolic rate, insulin resistance, inflammation
Tinius, RA, Blankenship, M, Maples, JM, Pitts, BC, Furgal, K, Norris, ES, Hoover, DL, Olenick, A, Lambert, J, and Cade, WT. Validity of the 6-minute walk test and Young Men's Christian Association (YMCA) submaximal cycle test during midpregnancy. J Strength Cond Res 35(11): 3236-3242, 2021-Submaximal exercise testing can be a feasible alternative to maximal testing within special populations to safely predict fitness levels; however, submaximal exercise testing has not been well-validated for use during pregnancy. The purpose of this study was to determine the concurrent validity of the 6-minute walk test (6MWT) and the YMCA submaximal cycle test (YMCAT) to predict V̇o2max in physically active women during midpregnancy. Thirty-seven (n = 37) pregnant women (22.1 ± 1.4 weeks' gestation) and 10 (n = 10) nonpregnant women participated in the study. Subjects completed a graded maximal treadmill test at 1 visit to measure maximal oxygen consumption (V̇o2max), and then subjects completed the 6MWT and YMCAT in randomized order during a separate visit. The predicted V̇o2max from each submaximal test were compared with the measured V̇o2max from the treadmill test to assess the validity of these tests during pregnancy. Among pregnant women, predicted V̇o2max from the YMCAT was not correlated to the measured V̇o2max (r = 0.14, p = 0.42), and the predicted V̇o2max from the 6MWT was only moderately correlated (r = 0.40, p = 0.016) to the measured V̇o2max. Among nonpregnant women, the predicted V̇o2max values from both the YMCAT and the 6MWT had strong correlations with the measured V̇o2max values (YMCAT: r = 0.71, p = 0.02; 6MWT: r = 0.80, p = 0.006). Neither test demonstrated concurrent validity among the pregnant sample. The main finding is that the YMCAT is not a valid method to estimate V̇o2max during midpregnancy (likely due to physiological changes in heart rate [HR] during pregnancy). The 6MWT has potential to be used clinically for estimating fitness as actual and predicted values did positively correlate, and it is not dependent on HR responses to exercise. However, if a precise measure of fitness is needed, then neither test appears to have strong validity for use during midpregnancy.
Only 30% of women achieve gestational weight gain (GWG) within recommended ranges set forth by National Academy of Medicine (NAM). Because extreme deviations from these recommendations for GWG have been associated with unfavorable maternal outcomes, a greater understanding of maternal metabolic factors that influence GWG is warranted. PURPOSE: The purpose of this study was to explore the potential link between maternal lipid metabolism and GWG. METHODS: Thirty-two women with a lean pre-pregnancy BMI were recruited during late pregnancy and fasting metabolic measurements using indirect calorimetry were assessed after an overnight fast. Fasting lipid oxidation rates were calculated using standardized equations. Pre-pregnancy weight and final delivery weight were self-reported and used to calculate total GWG, which was then categorized as follows: inadequate (below the NAM guidelines), adequate (adhered to the NAM guidelines), or excess (exceeded the NAM guidelines). One-way ANOVA with post-hoc Tukey tests were used to compare lipid oxidation rates across GWG categories and correlation coefficients were used to assess the relationship between GWG and maternal lipid oxidation. RESULTS: Fasting lipid oxidation was significantly higher (p < 0.05) among women with excess GWG compared to women with adequate GWG. Absolute GWG was positively correlated to lipid oxidation (r = 0.507, p = 0.003). CONCLUSIONS: The results from this study indicate that fasting lipid oxidation may play an important role in GWG. A better understanding of the metabolic profile of women during pregnancy may be critical in truly understanding a woman's risk of GWG outside the recommendations. Mounting evidence suggests that GWG counseling during prenatal care may need to be tailored to women based not just on their weight status, but other metabolic characteristic, in order to achieve GWG for optimal maternal health. Funding was provided by NIH NIGMS IDeA Grant 5P20GM103436 and WKU RCAP Grant 17-8011.
A plateau in volume of oxygen consumption (VO2) is the primary indicator for determining if an individual has reached their maximal aerobic capacity. However, secondary criteria can also be used to identify maximal effort (i.e. lactate level, rating of perceived exertion [RPE], percent of age-predicted maximal heart rate [HR] and respiratory exchange ratio [RER]). Age and gender-specific secondary criteria have been developed for the general population, but no secondary criteria have been established for pregnant women. The primary purpose of this study was to analyze secondary endpoint criteria during VO2max testing among pregnant women. A secondary purpose was to identify emotional and physical barriers pregnant women have that may prevent them from reaching maximal effort.Twenty-five pregnant women (age= 30.0±3.6 years; gestation age= 22.1±1.4 weeks, pre-pregnancy BMI= 23.68±4.04 kg/m2) participated. Each participant completed a Bruce protocol treadmill test and maximal HR, RER, lactate, and RPE were assessed and compared to standards. Barriers were assessed immediately postexercise via open-ended questions.The mean VO2max was 32.9±8.8 mL/kg/min. Mean RPEmax was 17.6±1.8 versus the standard of RPE≥17 (P=0.12). Percent of age-predicted HRmax was 88.0±6.8% versus the standard of ≥95% (P<0.001). Immediate postexercise lactate was 6.8±2.4mM versus the standard of ≥8 mM (P=0.03). Maximal RER was 1.2±0.2 versus the standard of RERmax ≥1.1 (P=0.08).Our data provide preliminary evidence that secondary criteria may need to be adjusted for pregnant women. Additionally, physical and emotional barriers may be enhanced by pregnancy (e.g. pain, discomfort, anxiety, health concerns), and may limit the performance of pregnant women during maximal exercise.
The relationship between metabolic flexibility (MF) and components of metabolic disease has not been well-studied among African American (AA) females and may play a role in the higher incidence of chronic disease among them compared with Caucasian American (CA) females. This pilot study aimed to compare the metabolic response of AA and CA females after a high-fat meal. Eleven AA (25.6 (5.6) y, 27.2 (6.0) kg/m2, 27.5 (9.7) % body fat) and twelve CA (26.5 (1.5) y, 25.7 (5.3) kg/m2, 25.0 (7.4) % body fat) women free of cardiovascular and metabolic disease and underwent a high-fat meal challenge (55.9% fat). Lipid oxidation, insulin, glucose, and interleukin (IL)-8 were measured fasted, 2 and 4 h postprandial. AA females had a significantly lower increase in lipid oxidation from baseline to 2 h postprandial (p = 0.022), and trended lower at 4 h postprandial (p = 0.081) compared with CA females, indicating worse MF. No group differences in insulin, glucose or HOMA-IR were detected. IL-8 was significantly higher in AA females compared with CA females at 2 and 4 h postprandial (p = 0.016 and p = 0.015, respectively). These findings provide evidence of metabolic and inflammatory disparities among AA females compared with CA females that could serve as a predictor of chronic disease in individuals with a disproportionately higher risk of development.
