Heat production during exercise in pregnancy: discerning the contribution of total body weight.

Studies have reported enhanced thermoregulatory function as pregnancy progresses; however, it is unclear if differences in thermoregulation are attributed to weight gain or other physiological changes. This study aimed to determine if total body weight will influence thermoregulation (heat production (Hprod)), heart rate, and perceptual measurements in response to weight-bearing exercise during early to late pregnancy. A cross-sectional design of healthy pregnant women at different pregnancy time points (early, T1; middle, T2; late, T3) performed a 7-stage weight-bearing incremental exercise protocol. Measurements of Hprod, HR, and RPE were examined. Two experimental groups were studied: (1) weight matched and (2) non-weight matched, in T1, T2, and T3. During exercise, equivalent Hprod at T1 (326 ± 88 kJ), T2 (330 ± 43 kJ), and T3 (352 ± 52 kJ) (p = 0.504); HR (p = 0.830); and RPE (p = 0.195) were observed in the WM group at each time point. In the NWM group, Hprod (from stages 1-6 of the exercise) increased across pregnancy time points, T1 (291 ± 76 kJ) to T2 (347 ± 41 kJ) and T3 (385 ± 47 kJ) (p < 0.001). HR increased from T1 to T3 in the warm-up to stage 6 (p = 0.009). RPE did not change as pregnancy time point progressed (p = 0.309). Total body weight, irrespective of pregnancy time point, modulates Hprod and HR during exercise. Therefore, accounting for total body weight is crucial when comparing thermoregulatory function during exercise across pregnancy.

Associations Between Rank, Sex, and Parity With Musculoskeletal Injuries Sustained During Annual Military Physical Fitness Test.

ABSTRACT: Edwards, CM, da Silva, DF, Puranda, JL, Souza, SCS, Semeniuk, K, and Adamo, KB. Associations between rank, sex, and parity with musculoskeletal injuries sustained during annual military physical fitness test. J Strength Cond Res 38(2): 367-373, 2024-Musculoskeletal injuries pose a significant threat to the well-being of military personnel. Attempts to use physical employment standard test results as predictors of injury are underway, but little is known about injuries sustained during the tests. This study sought to identify body regions most likely to be reported as injured during the annual Canadian Armed Forces (CAF) physical fitness evaluation. In addition, sex, rank, and parity status are explored as possible associated factors for injury. A total of 1,796 actively serving CAF members were categorized by sex (1,030 male participants; 766 female participants), rank (1,142 Non-Commissioned Members [NCM]; 638 Officers), and parity (314 parous female participants; 435 nulliparous female participants). Sex, rank, and parity were associated with body regions reportedly injured during an annual CAF fitness assessment (significance p ≤ 0.05). When compared with male participants, female participants were more likely to be injured {aOR: 1.797 (95% [confidence interval] CI: 1.45-2.23)} and more prone to injury of the wrist (adjusted odds ratio [aOR]: 1.933 [95% CI: 1.20-3.12]), hip (aOR: 3.445 [95% CI: 2.07-5.728]), or lower back (aOR: 1.55 [95% CI: 1.18-2.04]). Non-Commissioned Members were more likely to injure the neck (aOR: 2.14 [95% CI: 1.18-3.88]) or shoulder (aOR: 2.03 [95% CI: 1.31-3.15]), when compared with Officers. Parous female participants reported pelvis/abdomen injury at a higher rate than the nulliparous group (5 vs. 1.7%, p = 0.019). Injuries sustained during an annual CAF fitness assessment differ based on sex, rank, and parity. Canadian Armed Forces female participants, NCM, and parous female participants may require specific physical fitness support in preparation for the annual physical fitness test.

Heat loss responses at rest and during exercise in pregnancy: A scoping review.

BACKGROUND: The teratogenic risk associated with maternal hyperthermia (i.e., core temperature ≥39.0 °C) has been a crucial motive in understanding thermoregulatory responses in pregnancy. To date, a substantial number of studies have focused on core temperature responses in a wide range of exercise intensities, duration, and ambient temperatures. Fortunately, none have reported core temperatures exceeding 39.0 °C. Nonetheless, there are limited studies that have provided substantial insight into both dry and evaporative heat loss mechanisms involved in facilitating the maintenance of core temperature (≥39.0 °C) during heat stress in pregnant women. The purpose of this scoping review was to summarize the available literature that has assessed heat loss responses in studies of human pregnancy. METHODS: A search strategy was developed combining the terms pregnancy, thermoregulation, and adaptation. A systematic search was performed in the following databases: PubMed, Embase, Scopus, and ProQuest. Studies eligible for inclusion included pregnant women between the ages of 18-40 years old, and at least one measurement of the following: sweating, blood flow, skin temperature, and behavioural responses. Retrieved data were categorized as evaporative (sweating), dry or behavioural heat loss responses and summarized narratively. RESULTS: Thirty-three studies were included in this review (twenty-nine measured physiological responses and four measured behavioural responses). Studies suggest that during exercise, evaporative (sweating) and dry (skin blood flow and temperature) heat loss responses increase from early to late pregnancy in addition to greater cardiac output, blood volume and reduced vascular resistance. Behavioural practices related to heat loss responses are also influenced by cultural/religious expectations, personal preferences and sociodemographics. CONCLUSION: The findings from this review suggest that pregnancy modifies evaporative (sweating), dry and behavioural heat loss. However, future studies have an opportunity to compare heat loss measurements accounting for gestational weight gain and thermal sensation/comfort scale to associate physiological responses with perceptual responses across pregnancy.

How Many Valid Days Are Necessary to Assess Physical Activity Data From Accelerometry During Pregnancy?

BACKGROUND: The authors examined whether or not ≤3 days wearing Actical® accelerometers provided acceptable results in comparison with the recommendation of ≥4 days in women across gestation. METHODS: A total of 26, 76, and 57 participants at early, mid, and late pregnancy, respectively, were assessed. Participants were instructed to wear the device for 7 days and women who wore it for ≥4 days were included. For each participant, 3, 2, and 1 day(s) were randomly selected. Paired comparisons, intraclass correlations coefficients, and kappa statistics were performed for ≥4 days (criterion) versus 3, 2, and 1 day(s). Averages (in minutes per day) of sedentary time, light, moderate, vigorous, moderate to vigorous physical activity (PA) and steps per day were examined. RESULTS: When 3 valid days were compared with the criterion, no significant differences were found for any gestational period. The intraclass correlations coefficients were "high" for all PA-related variables. The k values varied from .819 to .838 across pregnancy ("strong"). Two and 1 valid day(s) versus the criterion showed significant differences in some PA intensities, reduced intraclass correlations coefficients, "moderate" k values for 2 valid days (.638-.788) and "minimal-to-moderate" k values for 1 valid day (.367-.755). CONCLUSION: In pregnant women during early, mid, and late pregnancy, PA data obtained from 3 valid days of wear was equivalent and agreed with ≥4 valid days.

Determination of minimal recording period to assess resting heart rate variability during pregnancy.

Traditionally, resting heart rate variability (rHRV) is measured for 10 min using the last 5 min for analyses (e.g., criterion period). It is unknown whether the measurement period can be shortened in pregnant women as there are currently no established standards. We aimed to compare shorter time segments (e.g., from the 1st to 10th minutes) of the parasympathetic index natural logarithm transformation of root mean square of successive R-R differences (Ln rMSSD) with the criterion period in pregnant and nonpregnant women. Twelve pregnant (age: 30.8 ± 3.4 years; gestational age: 20.1 ± 5.0 weeks) and 15 nonpregnant women (age: 29.8 ± 4.0 years) were included. rHRV was measured using a portable heart rate monitor for 10 min while sitting. Ln rMSSD difference/agreement between shorter time segments and criterion period was analyzed. The result observed between the 4th-5th minutes was the shortest time segment not different from/highly agreed with the criterion period in pregnant women (difference [95% confidence interval (CI)]: -0.10 [-0.22 to 0.02]/bias ± 1.96 × SD: -0.06 [-0.38 to 0.25]). In nonpregnant women, the 2nd-3rd-minute segment was the shortest with similar results (difference [95% CI]: -0.04 [-0.15 to 0.07]/bias ± 1.96 × SD: -0.03 [-0.39 to 0.32]). The Ln rMSSD was found to be stable from the 5th-10th minutes and the 3rd-10th minutes in pregnant and nonpregnant women, respectively. A shortened rHRV assessment can increase its applicability in clinical/exercise-training settings. Novelty Ln rMSSD can be measured for 5 min in pregnant women, with the last 1-min segment analyzed. The last 1-min segment from 3 min can be used for rHRV measurement in nonpregnant women. The shortened rHRV assessment can facilitate its applicability in clinical/exercise-training settings.

Changes in mood state and recovery-stress perception after an HRV-guided running program in untrained women / Cambios en el estado de ánimo y la percepción del estrés de recuperación después de un programa de carrera guiado por HRV en mujeres sin entrenamiento / Alterações no estado de humor e na percepção do estresse na recuperação após um programa de corrida guiada pela VFC em mulheres não treinadas

To determine the effects of HRV-guided running training on mood state and recovery-stress factors in untrained women. Thirty untrained women were randomized into two groups. The CG performed a pre-defined training program while the HRVG completed their running training regarding the intensity distribution according to the parasympathetic activity. The questionnaires of perception of recovery-stress and mood state were answered pre and post-training. The CG reported reduced emotional stress (-0.8 ± 1.3), conflicts/pressure (-0.8 ± 0.8), and increased sleep quality (0.9 ± 1.1), personal acceptance (0.9 ± 1.6), self-regulation (0.8 ± 1.3), specific recovery mean (0.6 ± 0.9), and total recovery mean (0.4 ± 0.7). The HRVG reported decreased general stress (-0.5 ± 0.8), emotional stress (-0.7 ± 1.2), social stress (-0.8 ± 1.0), lack of energy (-0.8 ± 0.8), general stress mean (-0.5 ± 0.8), and increased self-regulation (0.7 ± 1.1). This group also decreased tension (-2.8 ± 3.7), depression (-2.7 ± 4.2), anger (-2.8 ± 4.4) and fatigue (-2.7 ± 3.7) and TMD (-10.7 ± 14.2). HRVG reduced negative scales of mood state and stress factors that were not observed in the controls

Determinar los efectos del entrenamiento de carrera guiado por la VFC sobre el estado de ánimo y los factores de recuperación-estrés en mujeres no entrenadas. Treinta mujeres sin entrenamiento fueron separadas en dos grupos al azar. El GC realizó un programa de entrenamiento predefinido, mientras que el GVFC completó su entrenamiento de carrera con respecto a la distribución de intensidad según la actividad parasimpática. Los cuestionarios de percepción de recuperación-estrés y estado de ánimo se respondieron antes y después del entrenamiento. El GC presentó una reducción del estrés emocional (-0,8 ± 1,3), conflictos / presión (-0,8 ± 0,8) y una mayor calidad del sueño (0,9 ± 1,1), aceptación personal (0,9 ± 1,6), autorregulación (0,8 ± 1,3), media de recuperación específica (0,6 ± 0,9) y media de recuperación total (0,4 ± 0,7). El GVFC presentó una disminución del estrés general (-0,5 ± 0,8), estrés emocional (-0,7 ± 1,2), estrés social (-0,8±1,0), falta de energía (-0,8 ± 0,8), media de estrés general (-0,5 ± 0,8), y aumento de la autorregulación (0,7 ± 1,1). Hubo disminución de la tensión (-2,8 ± 3,7), depresión (-2,7 ± 4,2), ira (-2,8 ± 4,4), fatiga (-2,7 ± 3,7) y TAT (-10,7 ± 14,2) en el GVFC. El GVFC mejoró el estado de ánimo y factores de estrés que no se observaron en los controles

Determinar os efeitos do treinamento de corrida guiado pela VFC sobre o estado de humor e fatores de recuperação-estresse em mulheres não-treinadas. Trinta mulheres não-treinadas foram randomizadas em dois grupos. O GC realizou um programa de treinamento pré-definido, enquanto que o GVFC completou seu treinamento de corrida no que diz respeito à distribuição das intensidade segundo a atividade parassimpática. Os questionários de percepção da recuperação-estresse e estado de humor foram respondidos antes e após o programa de treinamento. O GC apresentou redução do estresse emocional (-0,8 ± 1,3), conflitos/pressão (-0,8 ± 0,8) e uma maior qualidade do sono (0,9 ± 1,1), aceitação pessoal (0,9 ± 1,6), auto-regulação (0,8 ± 1,3), média da recuperação específica (0,6 ± 0,9) e média da recuperação total (0,4 ± 0,7). O GVFC apresentou diminuição do estresse geral (-0,5 ± 0,8), estresse emocional (-0,7 ± 1,2), estresse social (-0,8 ± 1,0), falta de energia (-0,8 ± 0,8), média do estresse geral (-0,5 ± 0,8), e aumento da auto-regulação (0,7 ± 1,1). Houve diminuição da tensão (-2,8 ± 3,7), depressão (-2,7 ± 4,2), raiva (-2,8 ± 4,4), fadiga (-2,7 ± 3,7) e THT (-10,7 ± 14,2) no GVFC. O GVFC reduziu as escalas negativas de humor e fatores de estresse que não foram observados nos controles

Effects of a Preschool Intervention on Physical Activity and Body Composition.

OBJECTIVE: To investigate the effect of a preschool physical activity intervention program delivered in licensed childcare settings, with or without a parent-facilitated home component, on children's daily physical activity, sedentary time, and body composition. STUDY DESIGN: For this cluster randomized controlled trial, 18 childcare centers were randomly allocated in equal numbers to the typical curriculum comparison group, childcare intervention alone (CC), or childcare intervention with parental involvement. Accelerometers were used to asses physical activity and sedentary time, and body composition was measured by bioelectrical impedance. RESULTS: Linear mixed model regression analyses showed no differences between the CC, the childcare intervention with parental involvement, and the comparison groups in changes from baseline to 6 months in total physical activity (P for time × group interaction = .665) or moderate-to-vigorous physical activity (P for time × group interaction = .164) when adjusted for baseline physical activity levels. Furthermore, no group differences were found for changes in light physical activity, sedentary time, or anthropometric variables. CONCLUSIONS: An affordable and easily scalable preschool intervention program delivered in licensed childcare settings, with or without the addition of a parent-driven home physical activity promotion, seems to have no significant effect on physical activity, sedentary time, or body composition. TRIAL REGISTRATION: ISRCTN: ISRCTN94022291.

Placenta nutrient transport-related gene expression: the impact of maternal obesity and excessive gestational weight gain.

OBJECTIVE: Maternal obesity and excess gestational weight gain (GWG) increase the risk of delivering large infants. This study examined the associations between maternal obesity and GWG on the expression of genes involved in fatty acid, amino acid and glucose transport, and the mechanistic target of rapamycin (mTOR) and insulin signaling axes in the placenta. METHODS: Placenta samples were obtained from lean (n = 11) and obese (n = 10) women. Gene expression in the placenta was measured using polymerase chain reaction. RESULTS: There were no differences in placenta gene expression between the lean and obese women, with the exception of lower expression of mTOR in the women with obesity who delivered male offspring (obese n = 6; lean n = 7). GWG in excess of the upper limit of the body mass index (BMI) specific guidelines was correlated with increased expression of SNAT1 and decreased expression of FABP3, mTOR, IRS1 and IGF1R. CONCLUSIONS: Variations in GWG may alter the expression of genes involved in regulating placental nutrient transport. Future research on placental nutrient transport should account for the sex of the offspring and the percentage of GWG that is gained above the upper limit for the pre-pregnancy BMI.

Maternal-fetal nutrient transport in pregnancy pathologies: the role of the placenta.

Appropriate in utero growth is essential for offspring development and is a critical contributor to long-term health. Fetal growth is largely dictated by the availability of nutrients in maternal circulation and the ability of these nutrients to be transported into fetal circulation via the placenta. Substrate flux across placental gradients is dependent on the accessibility and activity of nutrient-specific transporters. Changes in the expression and activity of these transporters is implicated in cases of restricted and excessive fetal growth, and may represent a control mechanism by which fetal growth rate attempts to match availability of nutrients in maternal circulation. This review provides an overview of placenta nutrient transport with an emphasis on macro-nutrient transporters. It highlights the changes in expression and activity of these transporters associated with common pregnancy pathologies, including intrauterine growth restriction, macrosomia, diabetes and obesity, as well as the potential impact of maternal diet. Molecular signaling pathways linking maternal nutrient availability and placenta nutrient transport are discussed. How sexual dimorphism affects fetal growth strategies and the placenta's response to an altered intrauterine environment is considered. Further knowledge in this area may be the first step in the development of targeted interventions to help optimize fetal growth.

Child obesity and fitness levels among Kenyan and Canadian children from urban and rural environments: a KIDS-CAN Research Alliance Study.

OBJECTIVE: This study was designed to gather anthropometric and fitness-related data on Kenyan children living in urban (UKEN) and rural (RKEN) environments and to compare them with previous data collected on Canadian children in order to examine the potential nutrition-physical activity transition. METHODS: Height, weight, waist circumference, triceps skinfolds were directly measured on rural (RKEN) and urban Kenyan (UKEN) children (n = 179, 9-13 years) and compared with existing data from Canadian children living in urban and rural environments (n = 274, 9-13 years). Aerobic fitness was measured using the 20 m shuttle run, flexibility using the sit-and-reach test and isometric handgrip strength was assessed. RESULTS: None of the RKEN children were overweight or obese (OWO). However, 6.8% of UKEN boys and 16.7% of girls were OWO. The RKEN children had lower BMI, waist circumference, and triceps skinfolds than all other groups (UKEN, and Canadian: p < 0.05). UKEN children were leaner than Canadian children (p < 0.05). Male and female RKEN children had higher running speeds, and aerobic fitness than UKEN children (p < 0.001). Isometric strength was not different between Kenyan groups and was not different from urban living Canadian children. UKEN children were the least flexible group, and girls were more flexible than boys in all groups. CONCLUSIONS: Urban Kenyan children appear to be showing signs of the nutrition-physical activity transition, as judged by the anthropometric similarities to contemporary living Canadian children. Further support is provided by examining the difference in prevalence of overweight/obesity among UKEN compared with their RKEN counterparts and their lower aerobic fitness level.