Low Fitness Research Articles

P135 FITNESS INFLUENCES THE RELATIONSHIP BETWEEN EXERCISE BLOOD PRESSURE AND LEFT VENTRICULAR STRUCTURE: EVIDENCE FROM THE EXERCISE STRESS TEST COLLABORATION (EXERTION) STUDY

Background. A hypertensive response to exercise is associated with left ventricular (LV) remodelling, a principal sign of hypertensive heart disease. Fitness may modify this relationship, making clinical interpretation of peak exercise systolic blood pressure (SBP) challenging. This study examines the influence of fitness on the relationship between peak exercise SBP and LV structure. Methods. Cardiovascular structure and function (LV mass index (LVMI), LV relative wall thickness (RWT), cardiac output (CO) and total peripheral resistance (TPR)) were assessed at rest by echocardiography on 4,309 individuals (aged 58.6±12.7 years,52.0% male). SBP was measured at peak treadmill exercise, and fitness (exercise duration (minutes)) was grouped into thirds. Multiple regression analysis was conducted with fitness as an interaction term with peak exercise SBP, adjusted for age, sex, pre-exercise SBP, and cardiovascular disease (CVD) history. Results. Peak exercise SBP was similar across low (180±26.5mmHg), moderate (181±26.3mmHg) and high (182±24.5mmHg) fitness groups. Fitness modified the relationship between exercise SBP and LVMI; each 5mmHg increase in exercise SBP was associated with LVMI in moderate [0.27(0.10–0.43) and high [0.25(0.06–0.43)] fitness groups, which was not observed among those with low fitness [-0.05(-0.22–0.12)]. RWT increased with higher peak exercise SBP at all fitness levels (all p<0.001), with higher values among those with low fitness. Prevalence of LV concentric remodelling was highest in those with low fitness (29.9%) and lowest in those with high fitness (10.8%). A lower CO and higher TPR were observed in the low fitness group (7.5±2.5L/min and 14.3±5.1mmHg min/L) compared to those with high fitness (10.9±3.1L/min and 9.2±2.09mmHg min/L). Conclusion. Whilst a small effect, fitness modified the peak exercise SBP-LV structure relationship, such that for similar peak exercise SBP, those with low fitness exhibit a more adverse LV remodelling, with lower CO and higher TPR, compared to those with higher fitness. Considering fitness when interpreting SBP and cardiac imaging results from exercise stress testing may be relevant in identifying CVD risk and optimal patient management.

O95 HYPERTENSIVE RESPONSE TO EXERCISE RELATIVE-TO-FITNESS AND LEFT VENTRICULAR HYPERTROPHY ARE ASSOCIATED WITH INCREASED RISK OF CARDIOVASCULAR EVENTS: EVIDENCE FROM THE EXERCISE STRESS TEST COLLABORATION (EXERTION) STUDY

Background. A hypertensive response to exercise (HRE) is associated with a high prevalence of left ventricular hypertrophy (LVH), both being related to an increased risk of cardiovascular disease (CVD). However, these associations may be influenced by aerobic capacity (fitness). This study aimed to determine if an HRE considered relative-to-fitness and LVH are associated with increased risk for CVD events. Methods. Records for 4,307 individuals (aged 58.6±12.7 years, 52.0% male) who underwent exercise stress echocardiography were linked to administrative health datasets (hospital and emergency admissions) to ascertain CVD events (n=458, mean follow-up, 44.8±25.9 months). LVH presence/absence (LVH+/LVH-) was defined as LV mass index adjusted for body surface area around a cut point of ≥115 g/m2 for men and ≥95 g/m2 for women. HRE presence/absence (HRE+/HRE-) relative-to-fitness was defined as peak systolic blood pressure (SBP) divided by peak metabolic equivalents around a cut point of ≥90th percentile. Survival analysis using Cox-proportional hazard regression was used to compare CVD event rates across the four groups defined by the combinations of HRE+/HRE- with LVH+/LVH-, adjusted for age, sex, pre-exercise SBP, and CVD history. Results. Compared to the reference group (HRE-/LVH-), there was a stepwise increase in CVD event rate (Figure 1) across the following groups: HRE+/LVH- [Adjusted HR(95%CI), 1.34(1.02-1.76)], HRE-/LVH+ [Adjusted HR(95%CI), 2.1(1.6-3.76)], HRE+/LVH+ [Adjusted HR(95%CI), 2.55(1.64-3.97)]. Conclusion. Individuals with both HRE considered relative-to-fitness and LVH are at the highest risk of CVD events, greater than either clinical presentation alone. These results emphasise the need to address an HRE and low fitness in people with LVH to improve CVD risk management.

114 Prime Time of Life: A multimodal physical activity and health education programme for middle-aged and older adults

Abstract Prime Time of Life is inclusive of people living with clinical conditions and differing fitness and functional abilities. Health screening was conducted preprogramme, and specific clinical exercise advice and support was provided to participants by Dr Diane Cooper, Clinical Exercise Physiologist. Participants completed two 60-minute multimodal (cardiovascular fitness, strength, balance, flexibility) exercise classes per week and were also encouraged to complete additional classes in their purpose built on-demand exercise library. In all 60-minute exercise classes the exercise instructor demonstrated three different options for each exercise to cater for participants who were working at beginner, intermediate and advanced levels of fitness. Participants appreciated the adaptations and progressions that were available for all exercises as it enabled them to work to their ownability and progress and monitor progress throughout the programme. Each week a 20-minute health education workshop relevant to participants was delivered online via Zoom. The workshop was recorded, edited, and uploaded to YouTube to view on-demand. The link for each video was shared with participants weekly via email to support on-demand learning in addition to any other relevant supporting material such as a training diary. The Prime Time of Life programme increased participants upper and lower body strength, aerobic fitness and perceptions of physical and mental health (see chapter 3). This was in addition to increased confidence and feelings of positivity around the participants’ own management of healthy functional ageing (see chapter 3). Participants commented that they really enjoyed the Prime Time of Life programme. It increased their awareness on the importance of multimodal exercise for healthy ageing and that they felt empowered to continue training and improve their health in the long term. Following on from this successful programme a full train the trainer programme has been developed and piloted with 9 Local Sports Partnerships, 20 participants with further plans for upscaling.

Natural Flow Simulation in a Baisin considering Artificial Water Cycle

This study seeks to regionalize the parameters of the grid-based rainfall-runoff model (GRM) and simulate the natural flow considering an artificial water cycle. We established a water supply and demand network for the Han River basin, derived data related to the artificial water cycle through various organizations, and performed a water budget analysis by reflecting the simulated natural flow. When comparing the results of regionalization using only the Chungju Dam parameters and those using the Chungju Dam and Soyanggang Dam parameters, both results for the simulated flow showed good agreement with the observed flow, and the fitness evaluation results were also high (pentad: NSE 0.913–0.977, KGE 0.795–0.935, CC 0.974–0.995). The natural flow simulated by the GRM and TANK indicated that both models were able to reproduce the observed data well. Water budget analyses were performed for different time intervals, and daily analysis exhibited relatively lower fitness than pentad analysis (daily NSE 0.887-0.963, KGE 0.792-0.928, CC 0.960-0.990), but no significant difference was observed. The results indicated that the simulation of natural flow through the GRM was appropriate, and the model was sufficiently applicable to a disturbed watershed.

The influence of physical fitness on self-confidence and its impact on physical education academic achievement. A study on grade V school students

Background and Study Aim. Much of the crisis in the current education system is caused by students’ low physical fitness and self-confidence. This study aims to determine the effect of physical fitness on self-confidence and its impact on the academic achievement of Physical Education of Grade V Primary School students. Materials and Methods. This research is correlational. The subjects were Class V students in elementary schools, with a sample size of 115 students (66 males, 49 females, ages 10-12) selected through random sampling. Academic achievement was measured through Physical Education report card scores, physical fitness through the Indonesian Student Fitness Test (TKSI), and physical self-confidence through a self-confidence scale. Data analysis was performed using regression techniques via SPSS 21. Results. Physical fitness positively affected self-confidence (r = 0.259, p = 0.005 < 0.05) and Physical Education academic achievement (r = 0.513, p = 0.000 < 0.05). Self-confidence also significantly impacted Physical Education academic achievement (r = 0.519, p = 0.000 < 0.05). Conclusion. Better physical fitness enhances students’ self-confidence and positively influences their academic performance in Physical Education.

Secondary Prevention Program through Hybrid Tele-Cardiac Rehabilitation using a Combination of Vigorous-intensity Interval Training and Low-Intensity Home-based Exercise in Patient with Refractory Angina Post-Percutaneous Coronary Intervention

Background: Refractory angina (RA) refers to symptoms lasting >3 months due to reversible ischemia occurring with coronary artery disease, which cannot be controlled by increased medical therapy or revascularization including percutaneous coronary intervention (PCI). It may result in a significant impact on patient outcomes such as exercise limitation, biopsychosocial disorders, and decreased quality of life. Participation of patients with RA in cardiac rehabilitation (CR) reduces angina frequency and increases exercise capacity. Exercise-based CR also improves endothelial function, reduces oxidative stress and arterial stiffness, and improves myocardial perfusion. CR is also known as a secondary prevention program with the main goal to help patients return to their normal activities by increasing their functional capacity and preventing long-term complications. Case illustration: A 64-year-old male has undergone PCI and experienced RA. This patient was given a CR program to increase his functional capacity as a secondary prevention of cardiovascular disease through a center-based combined with a home-based CR program. Aerobic exercise given was hospital-based vigorous-intensity interval training and low-intensity home-based exercise. Problems found were refractory angina that often appeared during activity, and low cardiorespiratory endurance or muscular fitness. Angina symptoms and hand grip strength improved after 2 weeks, even though muscular fitness classification was still poor. During the program, he could achieve the exercise heart rate target without any symptoms. After 4 weeks, hand grip strength and physical activity were improved, and an exercise test revealed no symptoms during the test, appropriate hemodynamic response, and good fitness classification. However, there were still frequent VES with couplet episodes, so the patient was still classified as high-risk stratification. Although risk stratification was still high, the patient was allowed to enter phase III CR, with the prescription of moderate-intensity aerobic, low-intensity resistance, flexibility, and breathing exercises. These exercises were given based on recommendations for the average adult to maintain his level of physical activity and promote lifelong healthy behavior. Conclusion: Hybrid tele-cardiac rehabilitation through a combination of vigorous-intensity interval training and low-intensity home-based exercise in a patient with refractory angina post-PCI improved functional capacity as a key component for the prevention of long-term cardiac or non-cardiac complications.

The Effects of Blood Flow Restriction Aerobic Exercise on Body Composition, Muscle Strength, Blood Biomarkers, and Cardiovascular Function: A Narrative Review.

Blood flow restriction exercise has emerged as a promising alternative, particularly for elderly individuals and those unable to participate in high-intensity exercise. However, existing research has predominantly focused on blood flow restriction resistance exercise. There remains a notable gap in understanding the comprehensive effects of blood flow restriction aerobic exercise (BFRAE) on body composition, lipid profiles, glycemic metabolism, and cardiovascular function. This review aims to explore the physiological effects induced by chronic BFRAE. Chronic BFRAE has been shown to decrease fat mass, increase muscle mass, and enhance muscular strength, potentially benefiting lipid profiles, glycemic metabolism, and overall function. Thus, the BFRAE offers additional benefits beyond traditional aerobic exercise effects. Notably, the BFRAE approach may be particularly suitable for individuals with low fitness levels, those prone to injury, the elderly, obese individuals, and those with metabolic disorders.

Individualized activity recommendation based on a physical fitness assessment increases short- and long-term regular physical activity in people with multiple sclerosis in a retrospective cohort study.

Despite the evidence of beneficial effects of physical activity (PA), people with multiple sclerosis (pwMS) are less physically active than the general population. To increase PA in pwMS, we developed a structured individually tailored PA promotion program which is conducted within clinical practice in a university-based outpatient clinic since 2016. This study serves as retrospective quality control of this program. In a retrospective cohort study, we assessed the physical fitness of pwMS and the impact of the program on short- and long-term PA changes and behavioral determinants. The program consisted of four appointments each 2-4 weeks apart. Spiroergometric test results of female pwMS were compared to female non-MS controls who underwent a voluntary physical fitness analysis. The short version of the Freiburger questionnaire, self-developed questions and the modified Physical activity screening questionnaire (PASQ) were sent to all participants assessing the PA levels before the program, 3 months after the program (short-term), and at the time of the survey (long-term). Additionally, established questionnaires assessed behavioral determinants before the program and long-term. A total of 166 participants [mean age 38.32 (± 10.61 SD), mean EDSS 2.30 (±1.29 SD)] and mostly females (63.3%, n = 105) were included in the study and started the program. A total of 136 participants completed the program. Out of these 63.9% (n = 87) answered the questionnaires in 12.38 (±11.34 SD) months after finishing the program. At baseline female pwMS (n = 100) showed a lower physical fitness in comparison to non-MS controls (n = 26) (maximal workload (Watts): 138.86 ± 37.85 vs. 191.73 ± 45.25, p < 0.001; peak oxygen consumption (ml min-1 kg-1): 26.40 ± 7.23 vs. 31.56 ± 10.10, p = 0.020). pwMS were more regularly active in short- (62.1%) and long-term (55.2%) compared to baseline (24.2%, p < 0.001). Among the activated participants, we observed improved internal motivation (p = 0.002) and decreased perception of barriers (p = 0.006) compared to baseline. PwMS showed a lower physical fitness in comparison to non-MS controls. An individually tailored PA promotion program might improve behavioral determinants and thereby increase short- and long-term PA levels of pwMS.

High-intensity interval training improves cardiovascular and physical health in patients with rheumatoid arthritis: a multicentre randomised controlled trial

ObjectivesPatients with rheumatoid arthritis (RA) have substantially elevated risk for cardiovascular diseases, and low cardiorespiratory fitness (VO2max) is a major mediator. The aim of this assessor-blinded, two-armed multicentre randomised controlled...

DiADEM-Dance against Dementia-Effect of a Six-Month Dance Intervention on Physical Fitness in Older Adults with Mild Cognitive Impairment: A Randomized, Controlled Trial.

Background: Preserving health and physical fitness is critical to ensure independent living across the lifespan. Lower levels of physical fitness are associated with age-related cognitive decline and a higher prevalence of mild cognitive impairment (MCI). Thus, this study investigates the influence of a six-month dance intervention on selected measures of physical fitness in older adults with MCI. Methods: In this randomized controlled trial, 55 patients with MCI were randomized into a sportive dance training (IG; n = 26; age: 70.7 ± 5.6 years; 62% female) or an inactive control group (CG; n = 24; age: 69.1 ± 6.8 years; 46% female). The dance group received two 90 min dance training sessions per week over a duration of six-months, which focused on learning dance movement patterns. During the training sessions, heart rate was measured to control exercise intensity. Physical fitness was assessed using cardiopulmonary exercise testing (CPET), lower limb functional fitness via sit-to-stand test, handgrip strength, and heart rate variability (HRV). Results: We observed that the dance intervention preserved the cardiorespiratory fitness as measured by maximal oxygen uptake (VO2max) during CPET, which decreased in the CG. Furthermore, participants in the IG demonstrated increases in leg and handgrip strength, although these were not statistically significant. HRV displayed a non-significant decrease following the intervention. Conclusions: The results of this randomized controlled trial suggest that sportive dance training can preserve elements of physical fitness (i.e., cardiorespiratory fitness) in older adults with MCI. Although improvements in the other parameters (i.e., leg and handgrip strength) were statistically non-significant, likely due to the small sample size, stabilizing muscular fitness and preventing age-related decline in older adults with MCI is important for maintaining functional independence. For future studies, we recommend a longer training duration paired with precise control of regular physical activity levels, an important confounding factor.

Metabolic Heat Production Modulates the Cardiovascular Drift-V̇O2max Relationship Independent of Aerobic Fitness in Women.

The purpose of this study was to test the hypothesis that cardiovascular (CV) drift and associated decrements in maximal oxygen uptake (V̇O2max) are greater in high-fit compared to low-fit women during exercise at the same %V̇O2max, but comparable at the same rate of metabolic heat production. Six high-fit (HI) and 6 low-fit (LO) women cycled in 35 °C for 15 min or 45 min at the same relative intensity (60% V̇O2max; 15REL and 45REL) or fixed rate of heat production (500 W; 15FX and 45FX), immediately followed by a GXT to measure V̇O2max. The separate 15- and 45-min trials permitted measurements of V̇O2max over the same time interval as CV drift. During 45REL, higher heat production in HI (496 ± 51 W vs. 364 ± 44 W in LO) resulted in greater end-exercise core temperature (38.7 ± 0.4 °C vs. 38.2 ± 0.1 °C, P = 0.03); greater increases in HR [15 beats·min-1 (10%) vs. 10 beats·min-1 (6%), P = 0.03] and decreases in SV [11 mL·beat-1 (16%) vs. 5 mL·beat-1 (8%), P = 0.001]; and larger reductions in V̇O2max (16% vs. 5%, P = 0.04) compared to LO. During 45FX, temperature responses, CV drift and decreased V̇O2max were not different between groups (all P > 0.05), despite differences in %V̇O2max (60% vs. 75% for HI and LO, respectively). We conclude metabolic heat production modulates the CV drift-V̇O2max relationship, independent of fitness level. These results support previous findings showing the magnitude of CV drift is proportional to reductions in V̇O2max.

Less is more: CRISPR/Cas9-based mutations in DND1 gene enhance tomato resistance to powdery mildew with low fitness costs

Powdery mildew (PM), triggered by Oidium neolycopersici, represents a significant threat and a major concern for the productivity of tomato plants (Solanum lycopersicum L.). The presence of susceptibility (S) genes in plants facilitates pathogen proliferation and their dysfunction can lead to a recessively inherited broad-spectrum and durable type of resistance. Past studies have demonstrated that disrupting the function of DND1 (Defense No Death 1) increases plant resilience against various pathogens, such as powdery mildew (PM), but this comes at the cost of negatively affecting the overall health and vigor of the plant. To investigate the possibility of minimizing the adverse effects of the dnd1 mutation while boosting disease resistance, a CRISPR-Cas9 construct with four single guide RNAs targeting three exons of SlDND1 (Solyc02g088560.4.1) was designed and introduced into the tomato variety Moneymaker (MM) through Agrobacterium tumefaciens-mediated transformation. Three T1 lines (named E1, E3 and E4) were crossed with MM and then selfed to produce TF2 families. All the TF2 plants in homozygous state dnd1/dnd1, showed reduced PM symptoms compared to the heterozygous (DND1/dnd1) and wild type (DND1/DND1) ones. Two full knock-out (KO) mutant events (E1 and E4) encoding truncated DND1 proteins, exhibited clear dwarfness and auto-necrosis phenotypes, while mutant event E3 harbouring deletions of 3 amino acids, showed normal growth in height with less auto-necrotic spots. Analysis of the 3D structures of both the reference and the mutant proteins revealed significant conformational alterations in the protein derived from E3, potentially impacting its function. A dnd1/dnd1 TF2 line (TV181848-9, E3) underwent whole-genome sequencing using Illumina technology, which confirmed the absence of off-target mutations in selected genomic areas. Additionally, no traces of the Cas9 gene were detected, indicating its elimination through segregation. Our findings confirm the role of DND1 as an S-gene in tomato because impairment of this gene leads to a notable reduction in susceptibility to O. neolycopersici. Moreover, we provide, for the first time, a dnd1 mutant allele (E3) that exhibits fitness advantages in comparison with previously reported dnd1 mutant alleles, indicating a possible way to breed with dnd1 mutants.

Blood pressure response to graded bicycle exercise in males and females across the age and fitness spectrum.

Blood pressure (BP) responses to exercise are frequently measured, with the concern that greater increases are a marker of disease. We sought to characterize the normal exercise BP response in healthy adults and its relationships with age, sex, and fitness. 589 participants (median age 46 [IQR 24-56] years, 81% male) underwent cardiopulmonary exercise testing with repeated, automated BP measures. An exaggerated maximal systolic BP (SBPmax) was defined from current guidelines as ≥210 mmHg in males and ≥190 mmHg in females. Individual linear regression analyses defined the relationship between BP and workload (SBP/W-slope and DBP/W-slope). Participants with or without an exaggerated SBPmax and above or below median SBP/W-slope were compared. An exaggerated SBPmax was found in 51% of males and 64% of females and was more prevalent in endurance-trained athletes (males 58%, females 72%, p<0.001). The mean SBP/W-slope was lower in males (0.24±0.10 mmHg/W) than females (0.27±0.12 mmHg/W), p=0.031. In both sexes, peak oxygen uptake (VO2peak) was inversely correlated with SBP/W-slope (p<0.01). Those with an exaggerated SBPmax and below-median SBP/W-slope were 10 years younger and had a 20% higher VO2peak, on average (p<0.001). A non-exaggerated SBPmax and above-median SBP/W-slope was observed in older individuals with the lowest VO2peak. In a large cohort of healthy individuals, an exaggerated SBPmax was common and associated with higher fitness. In contrast, higher SBP indexed to workload was associated with older age, lower fitness, and female sex. Thus, sex, age and fitness should be considered when evaluating BP response to exercise.

Physical Deconditioning in Lung Cancer Patients Who Underwent Lung Resection Surgery in Spain: A Prospective Observational Study.

Lung resection represents the main curative treatment modality for lung cancer. These patients present with physical deterioration that has been studied previously using objective variables; however, no previous studies have evaluated the self-perceived physical fitness of these patients. For these reasons, to increase the current knowledge on lung cancer patients' impairment, the aim of this study was to characterize the self-perceived physical deconditioning of lung cancer patients undergoing lung resection in the short and medium term after surgery. A longitudinal, observational, prospective cohort study was performed in the Thoracic Surgery Service of the Hospital Virgen de las Nieves (Granada). Symptoms (pain, fatigue, cough and dyspnea) and physical fitness (upper and lower limbs) were assessed before surgery, at discharge and at one month after discharge. Among the total of 88 patients that we included in our study, significant differences were found at discharge in symptoms (p < 0.05) and physical fitness (p < 0.05). One month after surgery, higher levels of pain (p = 0,002) and dyspnea (p = 0.007) were observed, as well as poorer results in the upper (p = 0.023) and lower limbs' physical fitness, with regard to the initial values. Patients undergoing lung resection present an increase in symptoms and physical fitness deterioration at discharge, which is maintained one month after surgery.

Rapid phenotypic and genotypic change in a laboratory schistosome population.

Genomic analysis has revealed extensive contamination among laboratory-maintained microbes including malaria parasites, Mycobacterium tuberculosis and Salmonella spp. Here, we provide direct evidence for recent contamination of a laboratory schistosome parasite population, and we investigate its genomic consequences. The Brazilian Schistosoma mansoni population SmBRE has several distinctive phenotypes, showing poor infectivity, reduced sporocysts number, low levels of cercarial shedding and low virulence in the intermediate snail host, and low worm burden and low fecundity in the vertebrate rodent host. In 2021 we observed a rapid change in SmBRE parasite phenotypes, with a ~10x increase in cercarial production and ~4x increase in worm burden. To determine the underlying genomic cause of these changes, we sequenced pools of SmBRE adults collected during parasite maintenance between 2015 and 2023. We also sequenced another parasite population (SmLE) maintained alongside SmBRE without phenotypic changes. While SmLE allele frequencies remained stable over the eight-year period, we observed sudden changes in allele frequency across the genome in SmBRE between July 2021 and February 2023, consistent with expectations of laboratory contamination. (i) SmLE-specific alleles rose in the SmBRE population from 0 to 41-46% across the genome between September and October 2021, documenting the timing and magnitude of the contamination event. (ii) After contamination, strong selection (s = ~0.23) drove replacement of low fitness SmBRE with high fitness SmLE alleles. (iii) Allele frequency changed rapidly across the whole genome, except for a region on chromosome 4 where SmBRE alleles remained at high frequency. We were able to detect contamination in this case because SmBRE shows distinctive phenotypes. However, this would likely have been missed with phenotypically similar parasites. These results provide a cautionary tale about the importance of tracking the identity of parasite populations, but also showcase a simple approach to monitor changes within populations using molecular profiling of pooled population samples to characterize fixed single nucleotide polymorphisms. We also show that genetic drift results in continuous change even in the absence of contamination, causing parasites maintained in different labs (or sampled from the same lab at different times) to diverge.

Identification of heart rate dynamics during treadmill and cycle ergometer exercise: the role of model zeros and dead time

Background The response of heart rate to changes in exercise intensity is comprised of several dynamic modes with differing magnitudes and temporal characteristics. Investigations of empirical identification of dynamic models of heart rate showed that second-order models gave substantially and significantly better model fidelity compared to the first order case. In the present work, we aimed to reanalyse data from previous studies to more closely consider the effect of including a zero and a pure delay in the model. Methods This is a retrospective analysis of 22 treadmill (TM) and 54 cycle ergometer (CE) data sets from a total of 38 healthy participants. A linear, time-invariant plant model structure with up to two poles, a zero and a dead time is considered. Empirical estimation of the free parameters was performed using least-squares optimisation. The primary outcome measure is model fit, which is a normalised root-mean-square model error. Results A model comprising parallel connection of two first-order transfer functions, one with a dead time and one without, was found to give the highest fit (56.7 % for TM, 54.3 % for CE), whereby the non-delayed component appeared to merely capture initial transients in the data and the part with dead time likely represented the true dynamic response of heart rate to the excitation. In comparison, a simple first-order model without dead time gave substantially lower fit than the parallel model (50.2 % for TM, 47.9 % for CE). Conclusions This preliminary analysis points to a linear first-order system with dead time as being an appropriate model for heart rate response to exercise using treadmill and cycle ergometer modalities. In order to avoid biased estimates, it is vitally important that, prior to parameter estimation and validation, careful attention is paid to data preprocessing in order to eliminate transients and trends.

Effects of Aging, Fitness, and Cerebrovascular Status on White Matter Microstructural Health.

White matter (WM) microstructural health declines with increasing age, with evidence suggesting that improved cardiorespiratory fitness (CRF) may mitigate this decline. Specifically, higher fit older adults tend to show preserved WM microstructural integrity compared to their lower fit counterparts. However, the extent to which fitness and aging independently impact WM integrity across the adult lifespan is still an open question, as is the extent to which cerebrovascular health mediates these relationships. In a large sample (N = 125, aged 25-72), we assessed the impact of age and fitness on fractional anisotropy (FA, derived using diffusion weighted imaging, DWI) and probed the mediating role of cerebrovascular health (derived using diffuse optical tomography of the cerebral arterial pulse, pulse-DOT) in these relationships. After orthogonalizing age and fitness and computing a PCA on whole brain WM regions, we found several WM regions impacted by age that were independent from the regions impacted by fitness (hindbrain areas, including brainstem and cerebellar tracts), whereas other areas showed interactive effects of age and fitness (midline areas, including fornix and corpus callosum). Critically, cerebrovascular health mediated both relationships suggesting that vascular health plays a linking role between age, fitness, and brain health. Secondarily, we assessed potential sex differences in these relationships and found that, although females and males generally showed the same age-related FA declines, males exhibited somewhat steeper declines than females. Together, these results suggest that age and fitness impact specific WM regions and highlight the mediating role of cerebrovascular health in maintaining WM health across adulthood.

An improved Genghis Khan optimizer based on enhanced solution quality strategy for global optimization and feature selection problems

Feature selection (FS) is the activity of defining the most contributing feature subset among all used features to improve the superiority of datasets with a large number of dimensions by selecting significant features and eliminating redundant and irrelevant ones. Therefore, this process can be seen as an optimization process. The primary goals of feature selection are to decrease the number of dimensions and enhance classification accuracy in many domains, such as text classification, large-scale data analysis, and pattern recognition. Several metaheuristics, such as the Genghis Khan Shark Optimizer Algorithm (GKSO), can assist in optimizing the FS issue. However, these methods tend to converge towards local solutions with a low convergence rate. In order to address this issue in GKSO, a more refined version called I-GKSO is implemented. The I-GKSO suggested introducing a new approach to modify solutions that have low fitness values. In addition, it employs the Enhanced Solution Quality (ESQ) strategy to enhance the exploration phase. It utilizes Quasi-opposite-based learning (QOBL) to enhance the best solution obtained and, consequently, the entire population. The algorithm presented aims to solve the FS problem and has been assessed using benchmark optimization problems from the CEC’2017 and CEC’2022. To assess the efficacy of the I-GKSO, it has been subjected to comparisons with multiple different algorithms. The trials conducted using FS datasets yield a quantitative consideration of the I-GKSO's capacity to attain the most optimal subset of features. Furthermore, Wilcoxon and Friedman's non-parametric tests were accomplished to support the performance of the proposed method.

Identifying Risk Factors for Presarcopenia in Early Middle Age

ObjectiveThis study aimed to determine whether risk factors for presarcopenia can be identified in a sample of early middle-aged men and women. DesignProspective study. SettingLongitudinal data from the Dunedin Multidisciplinary Health and Development Study were used to investigate the relationship between presarcopenia at age 45 years and selected early markers at ages 26, 32, and 38 years. ParticipantsLongitudinal data from N=899 participants from the Dunedin Multidisciplinary Health and Development Study. InterventionsNot applicable. Main Outcome MeasuresPresarcopenia was defined as low relative appendicular lean mass index assessed by dual energy x-ray absorptiometry and low strength assessed by grip strength. Logistic regressions were used to describe the association between selected markers and presarcopenia at age 45 years. ResultsMultivariate logistic regression revealed that a higher body mass index (BMI) at ages 26, 32, and 38 years was associated with lower likelihood of presarcopenia at age 45 years in both men and women (odds ratio [OR] range, 0.46-0.64). Higher age-normative grip strength at age 38 years in both men and women (OR range, 0.88-0.92) was also associated with lower likelihood for presarcopenia. Lastly, lower self-perceived physical fitness level in men at age 38 years was associated with an increased likelihood of presarcopenia at age 45 years (OR, 9.35; 95% confidence interval, 3.28-26.70). ConclusionsBMI and strength were associated with lower likelihood of presarcopenia during middle age. A higher likelihood of presarcopenia was associated with sex-specific lower self-perceived physical fitness. These modifiable biomarkers may serve as targets for clinical screening and early intervention aimed at slowing or preventing progression to sarcopenia in old age.

Diet and exercise in relation to lower extremity artery disease.

Adherence to the Mediterranean diet (MeD) has been associated with a reduced incidence of peripheral arterial disease (PAD)/lower extremity arterial disease (LEAD) in observational trials and in a randomized trial. In secondary prevention, a lower hazard ratio for composite major adverse cardiovascular events has been associated with better adherence to MeD in a relatively small, randomized trial. This has not been confirmed in a sub-analysis of a large interventional trial of dual antithrombotic treatment. The effects of vegetarian, vegan or low carbohydrate/ketogenic diets on the incidence and outcomes of PAD/LEAD are not known. While abdominal obesity is associated with diabetes mellitus and PAD/LEAD, the lowest incidence of PAD/LEAD has been found in subjects with a body mass index 25-29.9 kg/m2. Malnutrition is a negative prognostic factor for survival of patients with chronic limb threatening ischemia. Physical activity (PA) is an acute stressor, but habitual recreational PA results in beneficial adaptations and improved health. In observational studies, lower levels of exercise and lower physical fitness have been associated with more prevalent PAD/LEAD. In contrast to coronary artery disease, that shows a reverse J-shaped relationship between long-term endurance exercise and coronary atherosclerosis, such a relationship is not known for PAD/LEAD. A general recommendation for maintaining cardiovascular health is performing regular moderate-intensity exercise with some vigorous-intensity aerobic PA, and resistance exercise at least twice a week. Combinations of healthy behaviors are more effective in preventing PAD/LEAD than a single behavioral component. In treatment of PAD/LEAD causing intermittent claudication, supervised walking training is recommended among measures of first-line treatment, while unsupervised walking training should be considered as an alternative.