Force-, power-, and elasticity-velocity relationships in walking,running, and jumping

Summary Ground reaction forces and mechanical power were investigated when the subjects walked normally, while they were racing or running at four speeds, and when they performed the running long jump take-off. In addition, the apparent spring constants of the support leg in eccentric and concentric phases were investigated at the four running speeds, during the running long jump take-off, and in the triple jump. Six club level track and field athletes, four national level long jumpers, and six national level triple jumpers took part in the study. Cinematographic technique and a mathematical model of hopping (Alexander and Vernon 1975) were employed in the analysis. Force and power values were found to vary in the following order (from highest to lowest): long jump take-off, maximal running speed, submaximal running (80, 60, and 40% of maximum speed), racing gait, and normal gait. The data disclosed that the measured parameters had the highest values in the long jump take-off performed by the long jump athletes. Their peak values were: resultant ground reaction force 3270±74 N and mechanical power 160.1±10.5 J×kg^–1×s^–1. For the track and field athletes the values were 2010±80 N and 126.0±12.6 J ×kg^–1×s^–1. The apparent spring constant values of the support leg in the national level jumper group were in eccentric phase 30.54±8.38 N×mm^–1 ×kg^–1 and in concentric phase 0.129±0.012 N×mm^–1×kg^–1. In the track and field athletes the values were 13.97±1.01 N×mm^–1×kg^–1 and 0.093±0.003 N×mm^–1×kg^–1, respectively. In general, the increase in force and mechanical power output was related to the value of the apparent spring constant of the support leg in the eccentric phase. The spring constant in the eccentric phase increased with the velocity of motion in running, the long jump take-off and the triple jump. This suggests that it may be possible to use this parameter as a measure of mechanical performance, as it may reflect the combined elasticity of muscles, tendons, and bones.     

Lifestyle, genetics, and disease in Sami

Aim

To present a summary of the lifestyle, genetic origin, diet, and disease in the population of Sami, indigenous people of northern Fennoscandia.

Method

A survey of the available scientific literature and preliminary results from our own study of the Swedish Sami population.

Results

The Sami probably have a heterogeneous genetic origin, with a major contribution of continental or Eastern European tribes and a smaller contribution from Asia. The traditional Sami diet, high in animal products, persists in Sami groups still involved with reindeer herding, but others have adopted a diet typical of Western cultures. Early reports indicated a lower prevalence of heart disease and most cancers, except stomach cancer. Recent studies have not found a lower risk of heart disease, but have consistently shown an overall reduced cancer risk. Sami have been reported to share some specific health-related genetic polymorphisms with other European populations, but none that would explain the observed differences in disease risk.

Conclusion

The genetic structure of the Sami population makes it suitable for studies of the genetic and environmental factors influencing the development of common diseases. The difference in incidence of heart disease between studies may reflect the ongoing transition from a traditional to a more Westernized lifestyle. The ability to compare population segments with different lifestyles, combined with the genetic structure of the population, creates unusual possibilities for studies of the genetic and environmental factors involved in the development of common disease.Sami are the indigenous people of the northernmost parts of Sweden, Finland, Norway, and the Kola Peninsula of Russia. The Sami speak a language belonging to the Finno-Ugric branch of the Uralic language family with Finns, Karelians, and Estonians as their closest linguistic neighbors. The Sami languages can be further divided into 10 distinct extant languages. Sami are believed to have been present in the area from soon after glacial ice-sheet retreated. The Sami where initially hunters (mainly of reindeer and moose), but over time they domesticated the reindeer and became reindeer herders. Today, the Sami population is estimated to be less than 100 000 individuals (1). Some of the Sami are still reindeer herders and maintain a traditional lifestyle linked to the annual migration of the reindeer between summer and winter grazing areas, while the rest have other occupations. The Sami population is not known to have experienced any dramatic population changes and until recent, marriages between Sami and non-Sami families have been infrequent.     

Catecholamines,growth hormone,cortisol, insulin,and sex hormones in anaerobic and aerobic exercise

Summary Seventeen male physical education students performed three types of treadmill exercise: (1) progressive exercise to exhaustion, (2) prolonged exercise of 50 min duration at the anaerobic threshold of 4 mmol·1^–1 blood lactate (AE), (3) a single bout of short-term high-intensity exercise at 156% of maximal exercise capacity in the progressive test, leading to exhaustion within 1.5 min (ANE).Immediately before and after ANE and before, during, and after AE adrenalin, noradrenalin, growth hormone, cortisol, insulin, testosterone, and oestradiol were determined in venous blood, and glucose and lactate were determined in arterialized blood from the earlobe. Adrenalin and noradrenalin increased 15 fold during ANE and 3–4 fold and 6–9 fold respectively during AE. The adrenalin/noradrenalin ratio was 13 during ANE and 110 during AE. Cortisol increased by 35% in ANE (12% of which appeared in the postexercise period) and 54% in AE. Insulin increased during ANE but decreased during AE. Testosterone and oestradiol increased by 14% and 16% during ANE and by 22% and 28% during AE. The results point to a markedly higher emotional stress and higher sympatho-adrenal activity in anaerobic exercise. Growth hormone and cortisol appear to be the more affected by intense prolonged exercise. Taking plasma volume changes and changes of metabolic clearance rates into consideration, neither of the exercise tests appeared to affect secretion of testosterone and oestradiol.Supported by Bundesinstitut für Sportwissenschaft, Köln-Lövenich     

Prevalence and diversity of Babesia,Hepatozoon, Ehrlichia,and Bartonella in wild and domestic carnivores from Zambia,Africa

A molecular survey was conducted for several hemoparasites of domestic dogs and three species of wild carnivores from two sites in Zambia. Three Babesia spp. were detected including Babesia felis and Babesia leo in lions (Panthera leo) and a Babesia sp. (similar to Babesia lengau) in spotted hyenas (Crocuta crocuta) and a single lion. All wild dogs (Lycaon pictus) and domestic dogs were negative for Babesia. High prevalences for Hepatozoon were noted in all three wild carnivores (38–61 %) and in domestic dogs (13 %). Significantly higher prevalences were noted in hyenas and wild dogs compared with domestic dogs and lions. All carnivores were PCR negative for Ehrlichia canis, Ehrlichia ewingii, and Bartonella spp. Overall, high prevalences and diversity of Babesia and Hepatozoon were noted in wild carnivores from Zambia. This study is the first molecular characterization of Babesia from any hyena species and is the first report of a Babesia sp. closely related to B. lengau, a parasite previously only reported from cheetahs (Acinonyx jubatus), in lions and hyenas. Although usually benign in wild carnivores, these hemoparasites can be pathogenic under certain circumstances. Importantly, data on vectors for these parasites are lacking, so studies are needed to identify vectors as well as determine transmission routes, infection dynamics, and host specificity of these hemoparasites in wildlife in Africa and also the risk of transmission between domestic animals and wildlife.     

Animated Randomness,Avatars, Movement,and Personalization in Risk Graphics

Background

Risk communication involves conveying two inherently difficult concepts about the nature of risk: the underlying random distribution of outcomes and how a population-based proportion applies to an individual.

Objective

The objective of this study was to test whether 4 design factors in icon arrays—animated random dispersal of risk events, avatars to represent an individual, personalization (operationalized as choosing the avatar’s color), and a moving avatar—might help convey randomness and how a given risk applies to an individual, thereby better aligning risk perceptions with risk estimates.

Methods

A diverse sample of 3630 adults with no previous heart disease or stroke completed an online nested factorial experiment in which they entered personal health data into a risk calculator that estimated 10-year risk of cardiovascular disease based on a robust and validated model. We randomly assigned them to view their results in 1 of 10 risk graphics that used different combinations of the 4 design factors. We measured participants’ risk perceptions as our primary outcome, as well as behavioral intentions and recall of the risk estimate. We also assessed subjective numeracy, whether or not participants knew anyone who had died of cardiovascular causes, and whether or not they knew their blood pressure and cholesterol as potential moderators.

Results

Animated randomness was associated with better alignment between risk estimates and risk perceptions (F _1,3576=6.12, P=.01); however, it also led to lower scores on healthy lifestyle intentions (F _1,3572=11.1, P<.001). Using an avatar increased risk perceptions overall (F _1,3576=4.61, P=.03) and most significantly increased risk perceptions among those who did not know a particular person who had experienced the grave outcomes of cardiovascular disease (F _1,3576=5.88, P=.02). Using an avatar also better aligned actual risk estimates with intentions to see a doctor (F _1,3556=6.38, P=.01). No design factors had main effects on recall, but animated randomness was associated with better recall for those at lower risk and worse recall for those at higher risk (F _1,3544=7.06, P=.01).

Conclusions

Animated randomness may help people better understand the random nature of risk. However, in the context of cardiovascular risk, such understanding may result in lower healthy lifestyle intentions. Therefore, whether or not to display randomness may depend on whether one’s goal is to persuade or to inform. Avatars show promise for helping people grasp how population-based statistics map to an individual case.     

Distribution and characteristics of ABFs, cecropins, nemapores, and lysozymes in nematodes

Several groups of antimicrobial effector molecules have been identified in nematodes, but most studies have been limited to Caenorhabditis elegans and, to a lesser extent, Ascaris suum. Although these two species are not closely related, they are not representative of overall nematode diversity. This study utilized available sequence information to investigate whether four groups of antimicrobial effectors (defensin-like antibacterial factors [ABFs], cecropins, saposin domain-containing proteins, and lysozymes) are components of an archetypal nematode immune system or more narrowly restricted. Saposin domain-containing proteins (caenopores in C. elegans) and lysozymes were widely distributed and found in most taxa, but likely have digestive as well as defensive functions. ABFs were widely distributed in fewer taxa, suggesting selective loss in some lineages. In contrast, cecropins were identified in only three related species, suggesting acquisition of this effector molecule in their common ancestor.     

Aldosterone low-dose,short-term action in adrenalectomized glucocorticoid-substituted rats: Na,K, Cl,HCO3, osmolyte,and water transport in proximal and rectal colon

The short-term action of aldosterone in physiological concentration on net fluxes of Na, K, Cl, HCO₃, osmolytes, and water was examined in the proximal colon and rectal colon of adrenalectomized (ADX) rats in vivo. The measuring time was 12 h, divided in eight periods of 90 min. (a) Aldosterone alone (6 nmol h^–1kg^–1) did not stimulate transport in ADX rats. In these experiments plasma [K] increased to fatal values. A basal glucocorticoid substitution of 24 nmol h^–1kg^–1 corticosterone caused plasma K to stay constant throughout the experiment, so that epithelial transport was not handicapped by non-specific effects of ADX, but this also did not restore the decreased transport of ADX rats to control values. Under these conditions (absence of aldosterone) in the rectal colon Na and H₂O transport was zero, whereas in the proximal colon flux rates were depressed by between 30% and 50%. In contrast, basal glucocorticoid substitution of 18 nmol h^–1kg^–1 corticoster-one plus infusion of 6 nmol h^–1kg^–1 aldosterone caused transport stimulation to values not significantly different from those of non-ADX controls.We conclude that after ADX, aldosterone at physiological concentrations increases transport if, as a prerequisite, a basal glucocorticoid substitution is provided. Transport of Na, K, and H₂O is under the total control of aldosterone in the rectal colon but is only moderately altered in the proximal colon. (b) In the proximal colon aldosterone is effective on electroneutral Na transport consistent with the Na/H, Cl/HCO₃ double exchanger, while in the rectal colon aldosterone controls the amiloride-sensitive Na channel, which is the sole apical Na transporter in that segment. In this respect the rectal colon is functionally distinct from the distal colon of other studies in the rat, where under unstimulated conditions the double exchanger is present. Regarding Na transport mechanisms, the rat large intestine thus consists of three distinct segments, the proximal, distal, and rectal colon. (c) In the rectal, but not the proximal colon, active net K absorption against the electrochemical gradient took place in the absence of aldosterone, but was suppressed in its presence. (d) The flux ratio of osmolytes over H₂O was constantly hypertonic as compared to the plasma (387±1 mosmol l^–1), independent of absolute flux size, the colonic segment examined, or the steroid concentration used. This effect may be due to a hypertonic unstirred layer within the lamina propria.Jx, transepithelial net flux of x, negative sign denotes secretion; ^ms transepithelial voltage, negative sign indicates luminal negativity     

HLA-A,B, DRB1, DQA1, DQB1 alleles and haplotype frequencies in Dene and Cree cohorts in Manitoba,Canada

Background

First Nations in the Canadian province of Manitoba have disproportionately high rates of epidemic and endemic TB. Gene polymorphisms that modulate HLA Class I and II antigens are among the risk markers for TB, along with other biologic, and social determinants of health. HLA-A, B, DRB1, DQA1, DQB1 were typed in two Manitoba First Nation indigenous groups to identify and compare the frequency of gene polymorphisms that may influence susceptibility or resistance to TB.

Lymphocytic ppENKmRNA,MEK-IR,and Dyn-IR in electroacupuncture

We studied the effect of acupuncture analgesia on the expression of ppENKmRNA, MEK-IR, and Dyn-IR in circulating mouse lymphocytes. Electroacupuncture stimulated cell immunity. The release of irDyn during electrostimulation at 5 Hz frequency was less active than irMEK release.__________Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 139, No. 6, pp. 667–668, June, 2005     

AIM2 inflammasome in infection,cancer, and autoimmunity: Role in DNA sensing,inflammation, and innate immunity

Recognition of DNA by the cell is an important immunological signature that marks the initiation of an innate immune response. AIM2 is a cytoplasmic sensor that recognizes dsDNA of microbial or host origin. Upon binding to DNA, AIM2 assembles a multiprotein complex called the inflammasome, which drives pyroptosis and proteolytic cleavage of the proinflammatory cytokines pro‐IL‐1β and pro‐IL‐18. Release of microbial DNA into the cytoplasm during infection by Francisella, Listeria, Mycobacterium, mouse cytomegalovirus, vaccinia virus, Aspergillus, and Plasmodium species leads to activation of the AIM2 inflammasome. In contrast, inappropriate recognition of cytoplasmic self‐DNA by AIM2 contributes to the development of psoriasis, dermatitis, arthritis, and other autoimmune and inflammatory diseases. Inflammasome‐independent functions of AIM2 have also been described, including the regulation of the intestinal stem cell proliferation and the gut microbiota ecology in the control of colorectal cancer. In this review we provide an overview of the latest research on AIM2 inflammasome and its role in infection, cancer, and autoimmunity.     

Noninvasive determination of the anaerobic threshold in canoeing,cross-country skiing,cycling, roller,and iceskating,rowing, and walking

Summary The relationship between velocity (V) and heart rate (HR) was determined in four canoeists, 42 cross-country skiers, 73 cyclists, nine ice-skaters, 10 roller-skaters, 32 rowers, and 20 walkers. The athletes were asked to increase their work intensity progressively, from low to submaximal velocities; HRs were determined by ECG in roller-, ice-skating, and walking, or read on a cardiofrequency meter in canoeing, cross-country skiing, cycling, and rowing.In all the athletes examined the linearity of the V-HR relationship was maintained up to a submaximal speed (deflection velocity, V_d), beyond which the increase in work intensity exceeded the increase in HR.V_d and anaerobic threshold (AT), determined through blood lactate measurements, were coincident in 19 athletes (6 cross-country skiers, 3 cyclists, 2 roller-skaters, 3 rowers, and 5 walkers).V_d was correlated with the average speeds maintained in walking (20km, n=13, r=0.88), cross-country skiing (15 km, n=20, r=0.80; 30 km, n=8, r=0.82; 12 km, n=7, r=0.86; 11 km, n=7, r=0.86) and cycling (1,000 m flying-start, n=68, r=0.83), thus showing that AT is a limiting factor in these aerobic events.     

Thinness,overweight, and obesity in indigenous school children and youth in Mexico

Abstract

Background: The prevalence of overweight (OWT) and obesity (OB), defined by the body mass index (BMI, kg/m²) among children and youth has increased worldwide in the last 30–40 years.

Aim: To evaluate the weight status, defined by the BMI, of indigenous school children and youth resident in different regions of Mexico

Subjects and methods: Students 6–18 years (31,448 boys, 27,306 girls) were enrolled in bilingual schools for indigenous children and youth in Mexico in 2012. Height and weight were measured; the BMI was calculated. The BMI of each student was classified relative to International Obesity Task Force (IOTF) age- and sex-specific criteria as thin (three grades), normal, overweight (OWT) or obese (OB). The sample was divided into five geographic regions for analysis: North, Central, South-Gulf, South-Pacific, and South-Southeast. Age- and sex-specific prevalence, 95% confidence intervals, and Chi-square tests were calculated.

Results: Prevalence of OWT?+?OB was highest in the South-Gulf, South-Pacific and South-Southeast regions and lowest in the North and Central regions, while thinness was most prevalent in the North and Central regions.

Conclusion: Prevalence of severe and moderate thinness was relatively low, while the combined prevalence of OWT?+?OB was generally more prevalent in indigenous boys than girls. However, the prevalence of thinness, OWT?+?OB among indigenous children and youth was lower than in the general population of children and youth in Mexico.     

Urbanization,migration, and indigenous health in Peru

Introduction

We compare demographic, socioeconomic, and anthropometric characteristics and blood pressure (BP), between rural and urban Peruvian indigenous women. These are preliminary results from a project on urbanization, migration, and health.

Methods

Data were collected cross-sectionally (2019) and compared between a rural (n = 92) and an urban (n = 93) community.

Results

Height: μ = 148.3 ± 5.0 cm (range = 137–162), weight: μ = 62.0 ± 11.5 (range = 37.5–108.7), median waist circumference = 89.0 (IQR = 15.8, range = 64.0–126.0), BMI = 28.3 (IQR = 6.2, range = 16.7–40.0), with no significant rural–urban differences. Systolic but not diastolic BP was significantly higher in urban versus rural women (median = 110, IQR = 18, range = 80–170 vs. median = 120, IQR = 10, range = 90–170, p = .002 and median = 70, IQR = 17, range = 50–100 vs. median = 70, IQR = 10, range = 60–100, p = .354), respectively.

Conclusions

Despite major lifestyle differences, there were no anthropometric differences between rural and urban women. Higher systolic BP in urban women may reflect social/economic stressors rather than dietary factors.     

Integrin expression in normal,hyperplastic, dysplastic,and malignant oral epithelium

We have examined the distribution of a range of integrin subunits in normal and lesional oral mucosa. The α₂, α₃, α₆, β₁β, and β₄ subunits were highly expressed in normal epithelium, and there was weaker, more variable expression of α₅ and α_v. Expression of all subunits was highest in the basal layer of normal epithelium, but extensive staining above the basal layer was also observed, particularly in the floor of the mouth and the lateral margin of the tongue. In dysplastic lesions and hyperplastic epithelium adjacent to ulcers, suprabasal staining was even more pronounced. Staining patterns in squamous cell carcinomas showed considerable variation, both within and between individual tumours: in some areas there was staining reminiscent of normal epithelium, but uniform staining throughout tumour islands, and patchy and variable cytoplasmic and pericellular staining were also seen. Thirteen out of 17 carcinomas showed some loss of integrin expression: six out of ten moderately well differentiated tumours and all the poorly differentiated tumours. Focal loss of a₆ and β₄ was most commonly observed, but loss of α₂ and β₃ also occurred. Since integrins regulate not only keratinocyte adhesion, but also the initiation of terminal differentiation, the changes in integrin expression that we have observed may have significance for the behaviour of individual tumours.     

Craniofacial,occlusal, and masticatory anatomy in bats

Skull measurements from ten anatomically and behaviorally diverse genera of bats show marked variation in positioning of the face upon the cranium but a relative stability of the site of the mandibular fossa. Factors associated with maintaining occlusion in bats which exhibit dorsally-inclined maxillary toothrows include dorsally angulated mandibular bodies and elevated condyles. Detailed comparisons are made between the generalized morphology of Myotis lucifugus and anatomical extremes represented by Rhinolophus lepidus, Mormoops megalophylla, and Pteropus giganteus. In these four bats, masticatory movements of the teeth and temporomandibular joints, despite marked interspecific variation, appear to relate to a common pattern. The beginning of jaw opening is important for maximal occlusal shear, particularly in Pteropus. Observed differences in the histology of the temporomandibular joints reflect postulated differences of pressure patterns within them. Differences in skeletal and dental morphology, together with variations in size and orientation of masticatory muscles, could account for known and postulated differences in the four respective chewing patterns, with no major variation from the known muscle firing sequences of Myotis lucifugus. Basic patterns of interaction between central nervous system and masticatory musculature would therefore appear to have undergone minimal modification. This accords with the concept that neural control of mastication is a relatively conservative mechanism; as such, it would appear to have imposed significant limitation upon adaptive change in bats.     

Clinical,serological, and molecular evidence of ehrlichiosis and anaplasmosis in dogs in Tunisia

A seroepidemiological survey was conducted in five bioclimatic areas of Tunisia to determine the prevalence of antibodies to Ehrlichia canis and Anaplasma phagocytophilum antigens, surrogate markers of the agents of canine monocytic ehrlichiosis (CME) and canine granulocytic ehrlichiosis, respectively. Among 286 collected sera, 54.2% and 25.2% were seropositive for E. canis and A. phagocytophilum, respectively, by the indirect immunofluorescence antibody (IFA) test. Clinical and hematological tests were done only for 58 sick dogs from Tunis area. A reverse line blot (RLB) hybridization was then used to identify isolated Ehrlichia and Anaplasma species infecting dogs (n = 228). Among them, only two dogs were infected by A. phagocytophilum; ten sample dogs were demonstrated infected by E. canis and ten infected by Ehrlichia sp., from which one dog showed a mixed infection with A. phagocytophilum and E. canis and one with A. phagocytophilum and Ehrlichia sp. RLB findings were confirmed by sequencing; BLAST search against GenBank revealed high similarity of the sequence of Ehrlichia sp. PCR/RLB amplicons with Anaplasma platys 16S rRNA partial sequence.     

Schizotypy,depression, and anxiety in physical and social anhedonia

Social anhedonia is a more promising indicator of vulnerability to schizophrenia than physical anhedonia, both as assessed by Chapman scales. More broadly, the populations identified by these scales would have a propensity to different psychiatric disorders. This cross‐sectional study examined the respective profiles of schizotypy, anxiety, and depression in French students with physical and social anhedonia, using psychometric and interview‐based measures. Compared to controls (n=46), subjects with social anhedonia (n=19) reported higher schizotypal scores for interpersonal, paranoid, disorganization, and cognitive/perceptual dimensions, whereas subjects with physical anhedonia (n=35) had more extensive interpersonal deficits and paranoia. Both groups had more depressive and anxiety symptoms than controls, in particular subjects with social anhedonia. © 2009 Wiley Periodicals, Inc. J Clin Psychol 65:1 –14, 2009.     

Maternal Levels of Prostacyclin,Thromboxane, ICAM,and VCAM in Normal and Preeclamptic Pregnancies

Citation Lewis DF., Canzoneri BJ., Gu Y, Zhao S, Wang Y. Maternal Levels of Prostacyclin, Thromboxane, ICAM, and VCAM in normal and preeclamptic pregnancies. Am J Reprod Immunol 2010; 64: 376–383 Problem To evaluate whether impaired endothelial function and endothelial inflammatory response occur in parallel in the women with preeclampsia. Method of Study Venous blood was drawn from normal (n = 40) and severe preeclamptic (sPE) (n = 40) pregnant women when they were admitted to the L&D Unit and 24 hrs after delivery. Plasma and serum samples were extracted and measured for 6‐keto PGF1α and TXB₂ (stable metabolites of PGI2 and TXA2), and intercellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM) by ELISA. Data are analyzed by Mann–Whitney test and paired t‐test. The statistical significance is set as P < 0.05. Results Plasma 6‐keto PGF1α levels were significantly reduced at admission and 24 hr after delivery in sPE compared to normal pregnant controls, P < 0.01. The ratio of 6‐keto PGF1α and TXB₂ was significant less in sPE than that in normal pregnant controls before delivery. There was no significant difference for ICAM and VCAM levels between normal and patients with sPE before and after delivery. Conclusion Maternal 6‐keto PGF1α levels and the ratio of 6‐keto PGF1α and TXB₂ were decreased in patients with sPE compared to normal pregnant controls. In contrast, maternal ICAM and VCAM levels were not different between the two groups. These data suggest that serum ICAM and VCAM levels may not be sensitive inflammatory biomarkers for preeclampsia.     

Association between Physical Activity,Sedentary Behaviors,Sleep, Diet,and Adiposity among Children and Adolescents in China

IntroductionPhysical activity (PA), sedentary behaviors (SB), sleep, and diet are related to adiposity among children and adolescents. However, there may be interactions between PA, SB, sleep, and diet, and these lifestyle behaviors may work together to affect body weight. The purpose of this study was to explore the impact of multiple lifestyle behaviors of PA, SB, sleep, and diet on childhood adiposity (body mass index z-score and overweight/obesity), and to investigate the effect of meeting multiple guidelines on adiposity among children and adolescents in China.MethodsCross-sectional results were based on 28,048 children aged 6–17 years from the China National Nutrition and Health Surveillance in 2010–2012. Information about PA, SB, and sleep was measured through interview-administered questionnaire. Dietary intake was assessed with food frequency questionnaire. The associations between multiple lifestyle behaviors and BMI z-score and overweight/obese were examined.ResultsThe prevalence of overweight/obesity in the participants was 19.2%. The average time of moderate-to-vigorous PA (MVPA), leisure SB, and sleep was 76.7 ± 45.5 min, 2.9 ± 1.4 h, and 8.5 ± 1.1 h per day, respectively. The China Dietary Guidelines Index for Youth (CDGI-Y) score was 62.6 ± 11.0. Sleep duration and diet score were negative associated with BMI z-score (both p < 0.001). MVPA and SB time were positive associated with BMI z-score (p = 0.041, 0.004). Meeting the SB, sleep, and diet guidelines had a lower BMI z-score (all p < 0.01) and lower odds of overweight/obesity (all p < 0.05). There were significant interactions between PA and diet. Compared with meeting no guidelines, those who met multiple guidelines had a lower risk of overweight/obesity (all p < 0.01). The more guidelines the participants met, the lower odds of overweight/obesity (p for trend <0.001).ConclusionsPA, SB, sleep, and diet are important behaviors associated with adiposity among children and adolescents. Attaining adequate amounts of appropriate multiple behaviors provided an additional benefit. It is important for children to meet recommended behavioral guidelines or recommendations. Interventions that aim to improve awareness of and compliance with these guidelines are needed in future.     

Heat stress and cardiovascular, hormonal, and heat shock proteins in humans

Context:

Conditions such as osteoarthritis, obesity, and spinal cord injury limit the ability of patients to exercise, preventing them from experiencing many well-documented physiologic stressors. Recent evidence indicates that some of these stressors might derive from exercise-induced body temperature increases.

Objective:

To determine whether whole-body heat stress without exercise triggers cardiovascular, hormonal, and extra-cellular protein responses of exercise.

Design:

Randomized controlled trial.

Setting:

University research laboratory.

Patients or Other Participants:

Twenty-five young, healthy adults (13 men, 12 women; age = 22.1 ± 2.4 years, height = 175.2 ± 11.6 cm, mass = 69.4 ± 14.8 kg, body mass index = 22.6 ± 4.0) volunteered.

Intervention(s):

Participants sat in a heat stress chamber with heat (73°C) and without heat (26°C) stress for 30 minutes on separate days. We obtained blood samples from a subset of 13 participants (7 men, 6 women) before and after exposure to heat stress.

Main Outcome Measure(s):

Extracellular heat shock protein (HSP72) and catecholamine plasma concentration, heart rate, blood pressure, and heat perception.

Results:

After 30 minutes of heat stress, body temperature measured via rectal sensor increased by 0.8°C. Heart rate increased linearly to 131.4 ± 22.4 beats per minute (F_6,24 = 186, P < .001) and systolic and diastolic blood pressure decreased by 16 mm Hg (F_6,24 = 10.1, P < .001) and 5 mm Hg (F_6,24 = 5.4, P < .001), respectively. Norepinephrine (F_1,12 = 12.1, P = .004) and prolactin (F_1,12 = 30.2, P < .001) increased in the plasma (58% and 285%, respectively) (P < .05). The HSP72 (F_1,12 = 44.7, P < .001) level increased with heat stress by 48.7% ± 53.9%. No cardiovascular or blood variables showed changes during the control trials (quiet sitting in the heat chamber with no heat stress), resulting in differences between heat and control trials.

Conclusions:

We found that whole-body heat stress triggers some of the physiologic responses observed with exercise. Future studies are necessary to investigate whether carefully prescribed heat stress constitutes a method to augment or supplement exercise.