Depression diagnostics using a nonlinear mathematical oscillatory model.

BACKGROUND AND OBJECTIVES: It is known that long-term stress leads to trauma and very often to depression. Usually, the diagnosis of depression is dealt with by psychiatrists who, based on conversations and questions, diagnose the patient's illness and condition. Unfortunately, this diagnosis is not always reliable. To prevent the development of disease, it is necessary to detect illness in a timely manner. One of the indications of the possibility of the onset of disease is a disturbance in the level of hormones in the body, especially cortisol. The purpose of this study was to develop a mathematical model for cortisol variation resulting from stress which would be useful in making conclusions about depressive states. METHODS: Rapid changes in cortisol concentration, according to ultradian rhythms, which are much faster than the daily circadian rhythm, is modelled as a truly nonlinear oscillator. The mathematical model contains two coupled first order differential equations. The stress is modeled as a pulsating action, described with a periodic trigonometric function, and cortisol production as a cubic nonlinear one. Three models for cortisol variation are considered: 1) the pure nonlinear model, 2) the periodically excited system, 3) and the chaotic system. The results from the study are supported with experimental measurements. RESULTS: Without stress, cortisol variation is of an oscillatory type with a constant steady-state amplitude. Intensive stress causes a resonant phenomenon in cortisol oscillatory variation. The occasion is short and is usually without consequences. For long stress periods deterministic chaos occurs which permanently changes the levels of cortisol. This phenomenon is an indicator of depression. Results from the suggested models are compared with experimentally obtained ones and good quantitative agreement is obtained. CONCLUSIONS: The nonlinear oscillator is a good model for indication of depression. The model provides not only general conclusions, but also individual ones, if personal characteristics are taken into consideration. Response of the model depends not only on the input data related to stress, but also on the system parameters that specify each individual. Findings obtained from this study have implications for the medical diagnosis and treatment of depression.

Physical Activity and Sedentary Behavior of Elderly Populations during Confinement: Results from the FRENCH COVID-19 ONAPS Survey.

Introduction: A national confinement was imposed in France in March 2020 during 55 days to prevent the spread of the virus and protect vulnerable people such as older individuals. This study aimed to describe the movement behaviors, and their determinants, of elderly people (≥ 65 years) during the confinement.Methods: An online survey was conducted from April 1st, 2020 to May 6th, 2020 by the National Observatory for Physical Activity and Sedentary behaviors. This study compared the level of physical activity (PA), sitting and screen time before and during the confinement and identified the impact of initial PA, sedentary profiles of the participants and housing conditions.Results: 1,178 people were included in this study. Reaching PA recommendations before lock-down was associated with the change in PA level during lock-down (p < .001). Besides, geographic location was associated with the change in PA, sitting time and screen time during lock-down (respectively p = .03, p = .02, p = .02).Conclusion: This study confirm the negative impact of confinement on senior movement behaviors, whether or not they met with public health recommendations prior to the pandemic. The housing conditions of older people must be also taken into future public health policies.

The economic costs of planting, preserving, and managing the world's forests to mitigate climate change.

Forests are critical for stabilizing our climate, but costs of mitigation over space, time, and stakeholder group remain uncertain. Using the Global Timber Model, we project mitigation potential and costs for four abatement activities across 16 regions for carbon price scenarios of $5-$100/tCO2. We project 0.6-6.0 GtCO2 yr-1 in global mitigation by 2055 at costs of 2-393 billion USD yr-1, with avoided tropical deforestation comprising 30-54% of total mitigation. Higher prices incentivize larger mitigation proportions via rotation and forest management activities in temperate and boreal biomes. Forest area increases 415-875 Mha relative to the baseline by 2055 at prices $35-$100/tCO2, with intensive plantations comprising <7% of this increase. Mitigation costs borne by private land managers comprise less than one-quarter of total costs. For forests to contribute ~10% of mitigation needed to limit global warming to 1.5 °C, carbon prices will need to reach $281/tCO2 in 2055.

The Effects of Concurrent Training Order on Satellite Cell-Related Markers, Body Composition, Muscular and Cardiorespiratory Fitness in Older Men with Sarcopenia.

OBJECTIVES: Concurrent Training (CT) is described as a combination of resistance training (RT) and endurance training (ET) in a periodized program to maximize all aspects of physical performance. To date, effects of CT order on muscular and cardiorespiratory fitness adaptations are controversial. Owing to the age-related decrement in satellite cells (SC) which are critical for fiber repair, conservation, muscle hypertrophy as well as cardiorespiratory fitness, the present study examined the response of SC related markers to CT order in older sarcopenic men. PARTICIPANTS: Thirty older men (age= 64.3 ± 3.5 years) were randomly assigned into one of 3 groups, ET followed by RT (E+R; n=10), RT followed by ET (R+E; n= 10) or a control (C; n=10). INTERVENTION: The training protocol consisted of 3 exercise sessions per week for 8 weeks. Blood samples were obtained at baseline and 48 hours after the final training session. RESULTS: Weight, skeletal muscle mass, lower and upper body power, maximal oxygen consumption (VO2max), Paired Box 7 (Pax7), and Myogenic factor 5 (Myf5) significantly increased, while were percent body fat significantly decreased following E+R and R+E compared to C. Importantly, the improvement in skeletal muscle mass, lower and upper body power, Myf5 and Pax7 in the E+R was significantly greater than the R+E group. Myogenin (Myog) and Paired Box 3 (Pax3) significantly increased (P < 0.01) in both training groups compared to no changes in C. CONCLUSION: An 8-week CT intervention improves SC related markers, body composition and enhances power and VO2max in older sarcopenic participants, regardless of the order of RT and ET. However, performing ET before RT may be more effective at enhancing skeletal muscle mass, Myf5 and Pax7, in addition to both lower and upper body power. While both CT programs produced notable physiological and performance benefits, performing ET before RT during CT may provide the greatest therapeutic benefits for aging individuals.

Effects of exercise training on multiple sclerosis biomarkers of central nervous system and disease status: a systematic review of intervention studies.

BACKGROUND AND PURPOSE: Multiple sclerosis (MS) is a demyelinating and neurodegenerative disease of the central nervous system (CNS) that can be tracked through biomarkers of disease status. We investigated the effects of exercise on MS biomarkers associated with CNS status including imaging, blood-brain barrier (BBB) function and neurotrophic factors. METHODS: We conducted open-dated searches of Scopus, Medline, EMBASE and the Cochrane Library. We included studies written in English describing interventions of exercise that measured one or more of the biomarkers associated with MS published up to October 2018. RESULTS: We located a total of 3012 citations through searches in electronic databases. Of these, 16 studies were eligible for review; six studies focused on magnetic resonance imaging (MRI) markers, nine studies focused on neurotrophic factors and three studies focused on BBB function markers. It is of note that two studies included both neurotrophic factor and BBB function markers and are therefore included across categories of biomarkers in this review. The existing evidence from MRI studies confirmed that exercise training can improve CNS integrity and function. There is evidence of a positive effect of exercise training on modulation of BBB permeability markers and brain-derived neurotrophic factor. CONCLUSIONS: Exercise successfully improves MRI outcomes and peripheral biomarkers (i.e. brain-derived neurotrophic factor) in people with MS. This suggests that exercise can be recommended as an adjuvant therapy for MS treatment. This conclusion is tempered by some methodological limitations including small sample sizes and high drop-out rates in the reviewed studies.

Potential complementarity between forest carbon sequestration incentives and biomass energy expansion.

There is a growing literature on the potential contributions the global forest sector could make toward long-term climate action goals through increased carbon sequestration and the provision of biomass for energy generation. However, little work to date has explored possible interactions between carbon sequestration incentives and bioenergy expansion policies in forestry. This study develops a simple conceptual model for evaluating whether carbon sequestration and biomass energy policies are carbon complements or substitutes. Then, we apply a dynamic structural model of the global forest sector to assess terrestrial carbon changes under different combinations of carbon sequestration price incentives and forest bioenergy expansion. Our results show that forest bioenergy expansion can complement carbon sequestration policies in the near- and medium-term, reducing marginal abatement costs and increasing mitigation potential. By the end of the century these policies become substitutes, with forest bioenergy expansion increasing the costs of carbon sequestration. This switch is driven by relatively high demand and price growth for pulpwood under scenarios with forest bioenergy expansion, which incentivizes management changes in the near- and medium-term that are carbon beneficial (e.g., afforestation and intensive margin shifts), but requires sustained increases in pulpwood harvest levels over the long-term.

Sitting to standing postural changes: Energy expenditure and a possible mechanism to alleviate sedentary behavior.

Background and aims Sedentary lifestyles have recently been identified as potential mechanism for obesity and associated metabolic diseases linked to ill health. The aim of this study was to investigate the effects of standing and sitting-standing positional changes on energy cost and consequently interrupting sedentary sitting time while working. Methods A total of 26 healthy male volunteers performed normal typing and editing work for 100 min under three conditions. The conditions included sustained sitting, sustained standing, and sitting-standing alternation every 20 min using a sit-stand desk. Respiratory parameters measured included minute ventilation (VE), oxygen consumption (VO2), and energy expenditure (EE). Measurements were recorded using a calibrated Cosmed K4b2 portable gas analysis system. Results The mean value for VE was the highest in the standing position (VE = 13.33 ± 0.71), followed by sitting-standing alternation (VE = 12.04 ± 0.62). Both were significantly different from sitting (VE = 10.59 ± 0.69). The maximum VE and EE for standing (VE = 14.81 ± 0.43 and EE = 1.84 ± 0.10) and sitting-standing alternation (VE = 14.80 ± 0.40 and EE = 1.93 ± 0.08) were significantly higher than that of sitting (VE = 12.15 ± 0.42 and EE = 1.67 ± 0.07). No significant differences were observed in the mean VO2 among the three conditions. However, the maximum VO2 for both standing (VO2 = 5.40 ± 0.20) and sitting-standing alternation (VO2 = 5.14 ± 0.17) had shown to be significantly higher than sitting (VO2 = 4.50 ± 0.18). There were no significant differences observed in the mean EE levels between sitting (EE = 1.43 ± 0.07) and sitting-standing alternation (EE = 1.55 ± 0.08). However, the mean EE while standing (EE = 1.62 ± 0.09) significantly increased compared to sitting. Conclusions The findings of this study indicate that sitting-standing alternations may be implemented as an effective intervention to interrupt prolonged sitting while working.

Utility of the hypertriglyceridemic waist phenotype in the cardiometabolic risk assessment of youth stratified by body mass index.

BACKGROUND: It is unclear whether the hypertriglyceridemic waist phenotype (HTWP) can be used to identify those at most risk of cardiometabolic disorders. OBJECTIVES: The utility of the HTWP as a useful predictor of cardiometabolic risk in youth stratified by body mass index was assessed. METHODS: Three hundred and eighty-seven children (12-17.5 years) were used within this cross-sectional study. Participants were classified as normal weight or overweight/obese according to the International Obesity Task Force criteria. The HTWP phenotype was defined as having a waist circumference ≥90th percentile for age and gender with concomitant triglyceride concentrations ≥1.24 mmol L(-1) . Cardiometabolic risk profiles were compared using MANCOVA. RESULTS: Normal weight participants with the HTWP had significantly higher levels of C-reactive protein 2.6 ± 0.4 vs. 1.6 ± 0.3 mg L(-1) (P < 0.05) and cardiometabolic risk scores (1.3 ± 0.3 vs. -0.7 ± 0.2 and 2.1 ± 0.4 vs. -0.5 ± 0.2; both P < 0.05) compared with those of a normal weight without the HTWP. Overweight/obese participants with the HTWP had significantly higher C-reactive protein levels (3.5 ± 0.6 vs. 2.6 ± 0.5; P < 0.05) as well as both cardiometabolic risk scores (1.6 ± 0.6 vs. 0.9 ± 0.2 and 2.2 ± 0.6 vs. 0.8 ± 0.2; both P < 0.001) when compared with overweight/obese participants without the HTWP. CONCLUSIONS: The HTWP may serve as a simple and clinically useful approach to identify youth at increased cardiometabolic risk.

Sprint interval training (SIT) is an effective method to maintain cardiorespiratory fitness (CRF) and glucose homeostasis in Scottish adolescents.

The present study examined the physiological impact of a school based sprint interval training (SIT) intervention in replacement of standard physical education (SPE) class on cardio-respiratory fitness (CRF) and glucose homeostasis during the semester following summer vacation. Participants (n=49) were randomly allocated to either intervention (SIT; n=26, aged 16.9 ± 0.3 yrs) or control group who underwent standard physical education (SPE; n=23, aged 16.8 ± 0.6 yrs). CRF (VO2max) and glucose homeostasis were obtained prior-to and following 7 weeks of SIT exercise. Significant group x time interaction was observed for CRF (P < 0.01) with non-significant trends for fasting insulin (P= 0.08), and HOMA-IR (P=0.06). CRF decreased (P < 0.01) in SPE such that POST intervention CRF was significantly lower (P< 0.05) in SPE. Fasting plasma glucose (P < 0.01), insulin (P< 0.01) and HOMA-IR (P< 0.01) increased significantly amongst SPE. The main finding of the present study is that 7-weeks of SIT exercise is an effective method of maintaining (but not improving) CRF and fasting insulin homeostasis amongst school-going adolescents. SIT exercise demonstrates potential as a time efficient physiological adjunct to standard PE class in order to maintain CRF during the school term.

The Kinematics and Kinetics Analysis of the Lower Extremity in the Landing Phase of a Stop-jump Task.

Large number of studies showed that landing with great impact forces may be a risk factor for knee injuries. The purpose of this study was to illustrate the different landing loads to lower extremity of both genders and examine the relationships among selected lower extremity kinematics and kinetics during the landing of a stop-jump task. A total of 35 male and 35 female healthy subjects were recruited in this study. Each subject executed five experiment actions. Lower extremity kinematics and kinetics were synchronously acquired. The comparison of lower extremity kinematics for different genders showed significant difference. The knee and hip maximum flexion angle, peak ground reaction force and peak knee extension moment have significantly decreased during the landing of the stop-jump task among the female subjects. The hip flexion angle at the initial foot contact phase showed significant correlation with peak ground reaction force during landing of the stop-jump task (r=-0.927, p<0.001). The knee flexion angle at the initial foot contact phase had significant correlation with peak ground reaction force and vertical ground reaction forces during landing of the stop-jump task (r=-0.908, p<0.001; r=0.812, P=0.002). A large hip and knee flexion angles at the initial foot contact with the ground did not necessarily reduce the impact force during landing, but active hip and knee flexion motions did. The hip and knee flexion motion of landing was an important technical factor that affects anterior cruciate ligament (ACL) loading during the landing of the stop-jump task.

Should an increase in cerebral neurochemicals following head kicks in full contact karate influence return to play?

BACKGROUND: Cerebral neurochemicals are markers of traumatic brain injury (TBI). OBJECTIVES: The aim of the study was to determine whether kicks to the head (KTH) in full contact karate significantly increased serum concentrations of protein S-100B, and neurone specific enolase (NSE). Kicks to the body (KTB) were also quantified to asses muscle tissue injury. Muscle damage was assessed by analysis of serum total creatine kinase (CK). METHODS: Twenty-four full contact karate practitioners were observed and filmed during actual competition and divided into two main groups post event: (1) Kicks to the head and body group (KTH): n = 12; mean ± SD; age, 30.4 ± 6.7 years; height, 1.74 ± 0.1 m; weight, 79.1 ± 2.1 kg; and (2): Kicks to the body group (KTB): n = 12; mean ± SD; age, 28.2 ± 6.5 years; height, 1.75 ± 0.1 m; weight, 79.2 ± 1.7 kg. The KTH group received direct kicks to the head, while group KTB received kicks and punches to the body. Blood samples were taken before and immediately post-combat for analysis of serum S-100B, NSE, CK and cardiac troponin. RESULTS: Significant increases in serum concentrations of S-100B (0.12 ± 0.17 vs. 0.37 ± 0.26, µg.L(-1)) and NSE (11.8 ± 4.1 vs. 20.2 ± 9.1 ng.mL(-1)) were encountered after combat in the KTH group and CK (123 ± 53 vs. 184 ± 103 U.L(-1)) in the KTB group (all P <0.05). CONCLUSIONS: Head kicks in full contact karate cause elevation of neurochemical markers associated with damaged brain tissue. The severity of injury is related to the early post-traumatic release of protein S-100B and NSE. The early kinetics and appearance post injury can reflect intracranial pathology, and suggest S-100B and NSE are extremely sensitive prognostic markers of TBI.

A consideration of the paradigm of exercise physiology.

Exercise physiology, in terms of the history of biological sciences, is quite young and has a rather tumultuous history - as it spans physical education, health & medicine, sport science, and biology. This has led to the development of differing definitions, research approaches, practices and goals. This is easily seen in the presence of competing and non-universally adopted definitions of fitness. Such internal inconsistencies portray to the outside world a discipline experiencing the problems associated with a changing paradigm. Every science requires the presence of a paradigm that both describes and guides the evolution of thinking, experimentation, and the application of such. It is argued here that exercise physiology has been operating without benefit of a satisfactory and relevant paradigm. A further proposition is that the required disciplinary definitions derived from an articulated paradigm are also absent. A paradigmatic scheme based on biological dogma is presented along with proposed definitions.

Strength and body composition changes in recreationally strength-trained individuals: comparison of one versus three sets resistance-training programmes.

PURPOSE: The purpose of this study was to determine the effects of increasing the volume of weight-training from one to three sets upon body composition and muscular strength. METHODS: Sixteen male weight-trainers volunteered to act as subjects and were randomly assigned to one of two training groups. Supervised weight-training targeting the upper body was conducted three times per week for eight weeks using one set (n = 8) or three sets (n = 8) of six repetitions to fatigue. Subjects were measured before and after the training intervention for (1) strength performance (N and kg) and (2) adiposity (sum of seven skinfold thicknesses in mm). RESULTS: Both training groups improved significantly (20.7%) in terms of muscular strength (P < 0.05) with no differences being observed between the one set (21.98% increase) and three set group (20.71% increase) after the training interventions (P > 0.05). Significant decreases were also observed for skinfold measures in the one set group (P < 0.05). CONCLUSIONS: One set of high intensity resistance training was as effective as three sets for increasing the strength of muscle groups in the upper body. The one set protocol also produced significantly greater decreases in adiposity.

Immunoendocrine responses over a three week international rugby union series.

AIM: This study evaluated changes in immunoendocrine makers over an international series in professional rugby union players (N.=8). METHODS: Venous bloods were taken on camp-entry, as well as before and after (0, 14 and 38 h) two games spaced over 21-days. Samples were analysed for changes in serum C-reactive protein (CRP), cortisol (C), testosterone (T), blood leukocytes, interleukin 6 (IL-6) and creatine kinase (CK). RESULTS: Significant reductions in CK activity and CRP concentrations were evident on day 5 (pre-game 1) when compared to camp-entry (day 1); P<0.05. A large acute-phase response was observed following both games. Differences in the magnitude of this response appeared dependant on the number of collisions players experienced during play. Compared to camp-entry, sharp increases in C (40%) and decreases (37%) in T were evident after both games; P<0.05. A gradual increase in T/C ratio was observed throughout the tournament; values 35% and 45% higher on days 19 and 21 than those observed at camp-entry (P<0.05). CONCLUSION: Current data suggests that improved physiological recovery can be achieved during an international rugby union series. Monitoring of previous club activity is essential to ensure optimal player readiness prior to participation in international rugby union games.

Direct hits to the head during amateur boxing is associated with a rise in serum biomarkers for brain injury.

Boxing exposes participants to the physiological response to high intensity exercise and also to direct body and brain trauma. Amateur boxing is increasing and females have also been included in the Olympics. The aim of this study is to assess the stress response and possible brain injury incurred during a match by measuring serum biomarkers associated with stress and cellular brain injury before and after combat. Sixteen male amateur boxers were studied retrospectively. The study population was divided into two groups: (a) a group that received predominantly punches to the head (PTH) and (b) a group that received predominantly punches to the body (PTB). Blood samples were taken before and five minutes after each contest. They were analysed for S-100B, neuron-specific enolase (NSE), creatine kinase (CK) and cortisol. The PTH group received direct contacts to the head (not blocked, parried or avoided) and to the body (n=8, age: 17.6 ± 5.3, years; height: 1.68 ± 0.13, meters; mass: 65.4 ± 20.3, kg). The PTB group received punches to the body including blocked and parried punches, but received no direct punches to the head, (n=8, mean ± SD, age: 19.1 ± 3.2 years; height: 1.70 ± 0.75, meters; mass: 68.5 ± 15 kg). Significant increases (P<0.05) were observed between pre- and post-combat serum concentrations in serum concentrations in PTH of S-100B (0.35 ± 0.61 vs. 0.54 ± 0.73, µg.L-1) NSE (19.7 ± 14 vs.31.1 ± 26.6, ng.ml-1) and cortisol (373 ± 202 vs. 756 ± 93, nmol.L-1). Significant increases (P<0.05) of creatine kinase were recorded in both groups. This study demonstrates significant elevations in neurochemical biomarkers in boxers who received direct blows to the head. However, further work is required to quantify this volumetric brain damage and long term clinical sequelae.

Physical activity interventions: effects of duration and intensity.

The purpose of this study was to examine the effects of exercising at different intensities over 7 weeks on components of physical fitness and CVD risk factors. Forty-seven boys and 10 girls, (16.4±0.7 years of age) were divided into a moderate, high intensity, or a control group. All participants had indices of obesity and blood pressure recorded in addition to four physical performance measures pre- and post-intervention. In addition, the intervention groups repeated the physical performance measures at the 4th week phase of the intervention. Following the intervention, significant improvements (P<0.05) in the high-intensity group were found in the 20 MSFT, agility, CMJ and 10 m sprint post-intervention. Participants in the moderate intensity group displayed significant improvements (P<0.05) in both the CMJ and 20 MSFT post-intervention. Body fat % significantly improved (P<0.01) in the moderate group only post-intervention. Interestingly, Systolic blood pressure significantly improved post-intervention (112±10 vs 106±11 mmHg) (P=0.017) in the high intensity group. In conclusion, high-intensity exercise over 7 weeks is a very time efficient means of improving important components of physical fitness in adolescents.

Secular trends in established and novel cardiovascular risk factors in Welsh 12-13 year olds: a comparison between 2002 and 2007.

BACKGROUND: This study examines CVD risk factors trends in Welsh adolescents between 2002 and 2007. PARTICIPANTS AND METHODS: CVD risk factor data was examined from two cross-sectional studies. The first study (73 participants; aged 12.9 ± 0.3 years) was completed in 2002. The second study (90 participants; aged 12.9 ± 0.4 years) was conducted in 2007. Measurements included body mass index (BMI), waist circumference (WC), total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, fibrinogen (Fg) and high-sensitivity C-reactive protein (hs-CRP). RESULTS: In boys, mean BMI and WC were lower in 2007, although not significantly (p ≥ 0.05). In 2007, there were improvements in mean lipid, Fg and hs-CRP concentrations in both sexes (p < 0.05). In 2002, 42.8% of boys and 34.2% of girls were overweight or obese; in 2007, this was 23.7% and 28.9% for boys and girls, respectively. More adolescents in 2002 exceeded the recommended levels for lipids, Fg and hs-CRP. CONCLUSION: This is the only study to examine CVD risk factor trends in Welsh adolescents. Although overweight continues to be widespread in 12-13 year olds, this study did not identify significant mean changes in overweight and obesity between 2002 and 2007. Overall, the data presented a positive trend in lipid profile and inflammatory factors.

Concentrations of salivary testosterone, cortisol, and immunoglobulin A after supra-maximal exercise in female adolescents.

The aim of this study was to examine the effect of supra-maximal exercise on circulating concentrations of salivary testosterone, salivary cortisol, and salivary immunoglobulin A in female adolescents. Nineteen apparently healthy females aged 15-16 years participated in this study. All participants completed 668 s sprints, interspersed with 30 s recovery intervals on a cycle ergometer. Salivary testosterone, cortisol, and immunoglobulin A samples were taken before and 5 min after exercise. Experimental procedures continued over two mornings, at least 3 h after a light breakfast. Participants refrained from performing any strenuous physical activity for at least 24 h prior to the exercise test. None of the participants were engaged in a structured training programme. The group mean (± s) for peak power output was 562 ± 113.0 W. Female adolescents recruited for this study showed no changes in salivary testosterone, cortisol or immunoglobulin A following repeated bouts of supra-maximal cycling (P > 0.05). To date, there has been a paucity of information concerning adolescents' hormonal and mucosal immune function responses to supra-maximal exercise. Our data provide further guidance with regard to physical activities and sports prescription for female adolescents. Further research, on a larger sample of females, is required to elucidate the physiological significance of these findings.