Healthy Young Female Participants Research Articles

Cooling collars incorporated with PCM packs and gels to improve indoor thermal comfort in healthy young females

The human neck is one of the most thermally sensitive body regions to nociceptive stimuli. Neck cooling has been extensively researched to improve athletic performance in the heat. However, there has been very little research into the use of conductive neck cooling for indoor thermal comfort. We thereby designed three ultralight cooling collars with cooling gels or phase change materials (GEL6, PCM15, and PCM18). Their cooling performance on thermal comfort enhancement of 14 healthy young female participants under two warm indoor temperatures (28 °C and 30 °C) was investigated. Thermophysiological and perceptual responses, including skin temperature, heart rate, sweating, thermal sensation vote (TSV), thermal comfort vote (TCV), and thermal preference vote (TPV), were extensively studied. Results showed that, in contrast to GEL6, PCM15 and PCM18 significantly decreased the neck skin temperature, with PCM15 exhibiting the greatest reduction of 4.37 °C at 28 °C. PCM15 and PCM18 significantly decreased overall and local TSVs while also increasing overall and local TCVs (all p < 0.05), thus they could maintain >80 % occupant satisfaction at 28 °C. At 30 °C indoor temperature, however, none of these three cooling collars were found to meet the 80 % occupant satisfaction criterion. When compared to GEL6, PCM15 and PCM18 were found to only significantly reduce local TSVs at the head and neck (all p < 0.05). In sum, PCM15 and PCM18 have the potential to increase acceptable HVAC summer cooling setpoint temperature by 2.5 °C, from 25.5 °C to 28.0 °C, leading to a 25 % reduction in building cooling energy consumption.

Prediction of Three-Directional Ground Reaction Forces during Walking Using a Shoe Sole Sensor System and Machine Learning.

We developed a shoe sole sensor system with four high-capacity, compact triaxial force sensors using a nitrogen added chromium strain-sensitive thin film mounted on the sole of a shoe. Walking experiments were performed, including straight walking and turning (side-step and cross-step turning), in six healthy young male participants and two healthy young female participants wearing the sole sensor system. A regression model to predict three-directional ground reaction forces (GRFs) from force sensor outputs was created using multiple linear regression and Gaussian process regression (GPR). The predicted GRF values were compared with the GRF values measured with a force plate. In the model trained on data from the straight walking and turning trials, the percent root-mean-square error (%RMSE) for predicting the GRFs in the anteroposterior and vertical directions was less than 15%, except for the GRF in the mediolateral direction. The model trained separately for straight walking, side-step turning, and cross-step turning showed a %RMSE of less than 15% in all directions in the GPR model, which is considered accurate for practical use.

Hypoxic Vasodilation is Augmented During the High versus Low Estrogen Phase of the Menstrual and Oral Hormonal Contraceptive Pill Cycle

BackgroundHypoxia elicits peripheral vasodilation to preserve oxygen delivery to metabolically active tissue. Hypoxic vasodilation, predominantly mediated by β‐adrenergic and nitric oxide mechanisms, is greater in adult female participants compared to adult male participants. Greater circulating estrogen in adult females has been purported to contribute to observed sex differences in hypoxic vasodilation. Nearly 80% of adult females in the United States will take oral hormonal contraceptive pills (OCPs) in their lifetime. Adult females taking OCPs exhibit greater β‐adrenergic receptor mediated vasodilation and nitric oxide production relative adult females with natural menstrual cycles (NC). Strategically utilizing the fluctuations of circulating estrogen that occur within a NC and OCP cycle, we aimed to examine the contribution of endogenous and exogenous estrogen on hypoxic vasodilation in female participants. We hypothesized female participants taking OCPs would exhibit greater hypoxic vasodilation relative to female participants with a NC. We further hypothesized hypoxic vasodilation would be greatest during the high estrogen (HE) phase of the menstrual or pill cycle compared to the low estrogen (LE) phase.MethodsTen female participants with a NC (25±1 yrs, 23±1 kg/m2) and ten female participants taking monophasic OCPs (24±1 yrs, 21±1 kg/m2) completed two study visits (IRB #2011312, NCT03606434). Participants were studied once during the LE phase of the menstrual or pill cycle (Cycle day: NC 3±1; OCP 5±1) and once during the HE phase of the menstrual or pill cycle (Cycle day: NC 15±1; OCP: 17±1). Forearm blood flow (venous occlusion plethysmography) and blood pressure (BP, finger plethysmography) were measured during normoxia and hypoxia (80% SpO2). Blood flow was normalized for BP and expressed as forearm vascular conductance (FVC).ResultsHypoxia elicited an increase in FVC (% change from baseline) that was greater during the HE phase (NC: 21±10%, OCP: 41±6%) of the menstrual/pill cycle compared to the LE phase (NC: 5±8%, OCP: 10±8%) in both NC and OCP participants (Main effect of phase, p&lt;0.01; Main effect of group, p=0.16; Interaction of phase and group, p=0.30).ConclusionHypoxic vasodilation is augmented in the HE phase of the menstrual and pill cycle in healthy young female participants, independent of whether the hormone is endogenous (NC) or exogenous (OCP). These data further our understanding of the role of estrogen in hypoxic vasodilation. These findings may have clinical implications for the vascular response to hypoxia in conditions of low estrogen (i.e., postmenopause) and/or estrogen excess, and warrant further investigation.

Metabolomics of Lean/Overweight Insulin-Resistant Females Reveals Alterations in Steroids and Fatty Acids.

The global diabetes epidemic is largely attributed to obesity-triggered metabolic syndrome. However, the impact of insulin resistance (IR) prior to obesity on the high prevalence of diabetes and the molecular mediators remain largely unknown. This study aims to compare the metabolic profiling of apparently healthy lean/overweight participants with IR and insulin sensitivity (IS), and identify the metabolic pathways underlying IR. In this cross-sectional study, clinical and metabolic data for 200 seemingly healthy young female participants (100 IR and 100 IS) was collected from Qatar Biobank. Orthogonal partial least square analysis was performed to assess the extent of separation between individuals from the 2 groups based on measured metabolites. Classical linear models were used to identify the metabolic signature of IR, followed by elastic-net-regularized generalized linear model (GLMNET) and receiver operating characteristic (ROC) analysis to determine top metabolites associated with IR. Compared to lean/overweight participants with IS, those with IR showed increased androgenic steroids, including androsterone glucuronide, in addition to various microbiota byproducts, such as the phenylalanine derivative carboxyethylphenylalanine. On the other hand, participants with IS had elevated levels of long-chain fatty acids. A ROC analysis suggested better discriminatory performance using 20 metabolites selected by GLMNET in comparison to the classical clinical traits (area under curve: 0.93 vs 0.73, respectively). Our data confirm the multifactorial mechanism of IR with a diverse spectrum of emerging potential biomarkers, including steroids, long-chain fatty acids, and microbiota metabolites. Further studies are warranted to validate these markers for diagnostic and therapeutic applications.

Morphological changes in the long axis of the lower leg muscles during isometric contraction in the sitting position.

[Purpose] To compare the changes in the muscle cross-sectional area (MCSA) along the long axis of the lower leg muscles at rest and during ankle plantar flexors isometric contraction and to obtain basic information regarding the movement of lower leg muscles during ankle plantar flexors contraction. [Participants and Methods] Sixteen healthy young female participants (20.9 ± 1.2 years) were asked to sit with their ankles in a neutral ankle position. Images were obtained at rest and during isometric contraction of the ankle plantar flexors using gravity magnetic resonance imaging. The MCSAs of the triceps surae and tibialis anterior were measured. [Results] The middle region of the soleus muscle had a lower MCSA on contraction than at rest. In addition, the medial head of the gastrocnemius had a lower MCSA on contraction than at rest in the distal quarter. Moreover, the tibialis anterior had a lower MCSA at rest than on contraction in the middle region. [Conclusion] The area to be used as an indicator and the movement to be induced differ depending on the muscle during isometric contraction of the triceps surae.

Effect of acute total sleep deprivation on plasma melatonin, cortisol and metabolite rhythms in females.

Disruption to sleep and circadian rhythms can impact on metabolism. The study aimed to investigate the effect of acute sleep deprivation on plasma melatonin, cortisol and metabolites, to increase understanding of the metabolic pathways involved in sleep/wake regulation processes. Twelve healthy young female participants remained in controlled laboratory conditions for ~92 hr with respect to posture, meals and environmental light (18:00–23:00 hr and 07:00‐09:00 hr <8 lux; 23:00–07:00 hr 0 lux (sleep opportunity) or <8 lux (continuous wakefulness); 09:00–18:00 hr ~90 lux). Regular blood samples were collected for 70 hr for plasma melatonin and cortisol, and targeted liquid chromatography–mass spectrometry metabolomics. Timepoints between 00:00 and 06:00 hr for day 1 (baseline sleep), day 2 (sleep deprivation) and day 3 (recovery sleep) were analysed. Cosinor analysis and MetaCycle analysis were performed for detection of rhythmicity. Night‐time melatonin levels were significantly increased during sleep deprivation and returned to baseline levels during recovery sleep. No significant differences were observed in cortisol levels. Of 130 plasma metabolites quantified, 41 metabolites were significantly altered across the study nights, with the majority decreasing during sleep deprivation, most notably phosphatidylcholines. In cosinor analysis, 58 metabolites maintained their rhythmicity across the study days, with the majority showing a phase advance during acute sleep deprivation. This observation differs to that previously reported for males. Our study is the first of metabolic profiling in females during sleep deprivation and recovery sleep, and offers a novel view of human sleep/wake regulation and sex differences.

INTERRELATIONSHIP OF STRESS, BODY IMAGE, NEGATIVE MOOD STATE AND SUSCEPTIBILITY TO ABNORMAL EATING BEHAVIOUR AMONG GAME SPECIFIC FEMALE ATHLETES: AN EXPLORATORY APPROACH

Purpose: To achieve and maintain a perfect body shape athlete often follows restrictive dieting which ultimately leads them to eating disorders. The purpose of the study was to identify whether there is an interrelationship of abnormal eating behaviours, perceived stress, negative mood state and self-perception of body image among athletic population and another was to observe the consequences of negative psychological well-being and game specificity on food choices and frequency. A secondary purpose of this study was to identify the “at risk-eating disorder” participants who were involved in different sports category. Methods: One thirty eight healthy young female participants matched for BMI were selected by purposive sampling. Subjects were divided into 4 categories i.e. aesthetic games group, endurance groups, strength group and healthy controls. Structured questionnaires were used for data collection during their non-competitive session. ANOVA followed by Scheffe’s test was applied to compare different parameters among the groups. Regression model examined the associations among disordered eating behaviours, stress, body shape concern, emotional eating, total mood disturbance and food choice. Findings: Result revealed disordered eating behaviour was significantly prominent in control and aesthetic game group than other two groups. Control group obtained the highest score in stress and emotional eating while aesthetic game group secured the highest score in body shape concern. Mood disturbance was more prevalent in strength group. Body mass index, body shape concern, emotional eating and total mood disturbance were identified as strongest predictor of EAT-26 scores. The result revealed that controls and aesthetic game group exhibit more abnormal eating behaviours than others. Value: This result will help to indicate abnormal eating behaviour and its relation with psychological well-being among female athletic population. Interventions programmes should be designed to cope up with competitive pressure to avoid abnormal eating behaviour. Article visualizations:

Gender Differences in Energy Expenditure During Walking With Backpack and Double-Pack Loads.

To investigate gender differences in energy expenditure during walking with backpack and double-pack loads. Studies have reported that energy expenditure during walking with double-pack loads is lower compared with backpack carriage. However, the effect of gender on energy expenditure while walking with these two load distribution systems has not been investigated. Thirty healthy young adults (15 female and 15 male participants) walked on a treadmill with backpack and double-pack loads weighing 30% of their body weight at a speed of 0.89 m/s for 10 min. The energy expenditure in terms of oxygen consumption (VO2) and respiratory exchange ratio (RER) were continuously monitored using a portable gas analyzer throughout each walking exercise. A mixed-design analysis of variance model was adopted to test the effects of gender, pack, and time on VO2 and RER. No time effect was observed on VO2. However, significant gender, pack, and interaction effects were observed. The lowest VO2 was found in female participants under double-pack carriage. No significant gender or pack differences existed in RER. However, RER significantly and incrementally increased in time from the 4th through 6th, 8th, and 10th min. This study revealed that heavy double-pack load carriage for healthy young female participants had significantly lower energy expenditure (normalized by the entire system weight, i.e., the participant's weight plus the weight of the pack) than that of the male participants in a 10-min walking exercise. The findings of this study indicated that healthy young female participants carried a heavy double-pack with less energy cost (normalized by the entire system weight, i.e., the participant's weight plus the weight of the pack) compared with their male counterparts during a 10-min walking exercise.

Movement Accuracy Changes Muscle-Activation Strategies in Female Subjects During a Novel Single-Leg Weight-Bearing Task

Understanding of how female subjects learn to move accurately during a resisted weight-bearing task is limited. The purpose of this study was to examine the muscle activation patterns used by female subjects in learning a novel single-leg squat (SLS) task under visual and nonvisual conditions. Prospective training study. University research setting. Ten healthy young female participants. Subjects tracked a sinusoidal target (knee displacement) during a resisted SLS exercise during the course of 4 days, under eyes open (EO) and eyes closed (EC) conditions with the use of a custom-designed weight-bearing exercise device. The accuracy of performance in tracking the target and electromyographic activity (EMG) of 5 muscles around the knee were monitored. Subjects improved their accuracy of performance by day 2 (40% decrease in error) and retained the accuracy on day 4. Error during the EC condition was 3 times greater than EO condition. Quadriceps-to-hamstrings coactivation ratio increased with the improved accuracy from the learning. Absence of visual feedback was accompanied by a decrease in the quadriceps-to-hamstrings coactivation ratio for this task. The muscle synergistic activity around the knee changes as the accuracy of the task improves during a resisted weight-bearing task. This activation pattern represents a feed forward control plan that the central nervous system adopted to optimize accurate weight-bearing knee displacement. Rehabilitation specialists should consider manipulating the visual feedback and accuracy of performance when developing weight-bearing rehabilitation training protocols to improve neuromuscular control in female patients.

The Hippocampus and Delayed Recall: Bigger is not Necessarily Better?

Healthy young female participants were tested on a measure of delayed verbal recall and then received volumetric Magnetic Resonance Imaging (MRI) scans. The analysis of the MRI scans focused on the volume of the hippocampus. Left hippocampal volume was negatively associated with the level of delayed verbal recall performance. This relationship was confirmed in further testing. This finding is consistent with a previous report of a similar relationship in healthy elderly individuals, but not in patients with Alzheimer's disease, in whom the opposite relationship was observed. An explanation of these findings in terms of impaired neural pruning of the hippocampus is advanced, whereby insufficient pruning of the hippocampus during childhood and adolescence (following adequate growth) may lead to reduced mnemonic efficiency.