UNASSIGNED: This study examines the causal effects of varying exercise intensities on type 2 diabetes mellitus (T2D) through Mendelian randomization (MR) analysis, using genetic variants as instrumental variables.
UNASSIGNED: A two-sample MR analysis was performed, employing Inverse Variance Weighted (IVW) as the primary method, supported by weighted median, MR-Egger regression, MR-PRESSO, and MR robustness-adjusted contour scores. Data were obtained from the International Exercise Genetics Database (IEGD) and the Global Diabetes Research Consortium (GRC), encompassing over 150,000 individuals for exercise intensity and around 200,000 T2D patients and controls. SNPs linked to exercise intensity were selected based on genome-wide significance (P < 5 × 10^-8) and linkage disequilibrium criteria (distance >10,000 kb, r^2 < 0.001).
UNASSIGNED: The IVW analysis suggested that high-intensity exercise might reduce T2D risk, but the association was not statistically significant (OR = 0.667, 95% CI = 0.104-4.255, P = 0.667). The wide confidence interval indicates uncertainty in the effect estimate. Low-intensity exercise showed no significant effect on T2D risk (OR ∼ 1.0). Sensitivity analyses, including weighted median and MR-Egger regression, confirmed no significant association between high-intensity exercise and T2D risk. The MR-PRESSO analysis found no significant outliers, and the global test for pleiotropy was non-significant (P = 0.455). Cochran\'s Q test for heterogeneity in the IVW analysis was non-significant (Q = 12.45, P = 0.234), indicating consistency among SNP-derived estimates.
UNASSIGNED: High-intensity exercise potentially reduces T2D risk, but the association is not statistically significant. Further research is needed to understand the complex relationship between exercise intensity and T2D.

The short-term scaling exponent of detrended fluctuation analysis (DFAα1) applied to interbeat intervals may provide a method to identify ventilatory thresholds and indicate systemic perturbation during prolonged exercise. The purposes of this study were to (i) identify the gas exchange threshold (GET) and respiratory compensation point (RCP) using DFAα1 values of 0.75 and 0.5 from incremental exercise, (ii) compare DFAα1 thresholds with DFAα1 measures during constant-speed running near the maximal lactate steady state (MLSS), and (iii) assess the repeatability of DFAα1 between MLSS trials. Twelve runners performed an incremental running test and constant-speed running 5% below, at, and 5% above the MLSS, plus a repeat trial at MLSS. During 30-min running trials near MLSS, DFAα1 responses were variable (i.e., 0.27-1.24) and affected by intensity (p = 0.031) and duration (p = 0.003). No difference in DFAα1 was detected between MLSS trials (p = 0.597). In the early phase (~ 8 min), DFAα1 measures at MLSS (0.71 [0.13]) remained higher than the DFAα1 identified at RCP from the incremental test (0.57 [0.13]; p = 0.024). In addition, following ~ 18 min of constant speed running at MLSS, DFAα1 measures (0.64 [0.14]) remained higher than 0.5 (p = 0.011)-the value thought to demarcate the boundaries between heavy and severe exercise intensities. Accordingly, using fixed DFAα1 values associated with the RCP from incremental exercise to guide constant-speed exercise training may produce a greater than expected exercise intensity, however; the dependency of DFAα1 on intensity and duration suggest its potential utility to quantify systemic perturbations imposed by continuous exercise.

To investigate the release of lipolytic hormones during various high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT), and their effects on fat loss. 39 young women categorized as obese (with a body fat percentage (BFP) ≥30%) were randomly allocated to one of the following groups: all-out sprint interval training (SIT, n =10); supramaximal HIIT (HIIT120, 120%V̇O2peak, n = 10); HIIT (HIIT90, 90%V̇O2peak, n = 10), or MICT, (60%V̇O2peak, n = 9) for a twelve-week observation period consisting of 3 to 4 exercise sessions per week. Serum epinephrine (EPI) and growth hormone (GH) were measured during the 1st, 20th, and 44th training sessions. Body weight (BW), body mass index (BMI), whole-body fat mass (FM) and BFP were assessed pre- and post-intervention. Following the 1st and 20th sessions, significant increases in EPI (p < 0.05) were observed post-exercise in HIIT120 and HIIT90, but not in SIT and MICT. In the 44th session, the increased EPI was found in SIT, HIIT120, and HIIT90, but not in MICT (p < 0.05). For the GH, a significant increase was observed post-exercise in all groups in the three sessions. The increased EPI and GH returned to baselines 3 hours post-exercise. After the 12-week intervention, significant reductions in FM and BFP were found in all groups, while reductions in BW and BMI were only found in the SIT and HIIT groups. Greater reductions in FM and BFP, in comparison to MICT, were observed in the SIT and HIIT groups (p < 0.05). 12-week SIT, HIIT120, and HIIT90, in comparison to MICT, were more efficacious in fat reduction in obese women, partly benefiting from the greater release of lipolytic hormones during training sessions.

BACKGROUND: Exercise interventions are highly effective at preventing falls in older people living in the community. In residential aged care facilities (RACFs), however, the evidence for effectiveness is highly variable, warranting exploration of drivers of successful trials. This study aims to identify the conditions of randomised controlled trials (RCTs) that are associated with reducing falls in RACFs and test whether it can explain the variability.
METHODS: RCTs testing exercise interventions in RACFs compared to usual care, reporting rate or risk of falls from the 2018 Cochrane Collaboration review and a search update to December 2022 were included. Two authors independently extracted and coded trial conditions and outcomes according to a theory developed from prior Intervention Component Analysis. Trial outcomes were coded as successful or unsuccessful based on point estimates for the rate or risk ratio for falls, or p value. Qualitative Comparative Analysis (QCA), utilising Boolean minimisation theory, was conducted to determine the key conditions driving trial success. A subgroup meta-analysis and the GRADE approach was applied to the final theory.
RESULTS: Eighteen trials undertaken in 11 countries with 2,287 residents were included. Participants were predominately ambulant females aged 70 to 80 with cognitive impairment. Most interventions were fully supervised or supervised at the start of the intervention. QCA identified two configurations as drivers of successful exercise falls prevention programs: (i) group exercise that is moderate or low intensity, or (ii) for independent ambulatory residents, exercise for more than 1 h per week. The combination of configuration (i) and (ii) had consistency and total coverage scores of 1, indicating all trials were explained. This combination was associated with a reduction in falls (rate ratio 0.45, 95%CI 0.34 to 0.59; risk ratio 0.66, 95%CI 0.53 to 0.82; low certainty evidence).
CONCLUSIONS: To successfully reduce falls in RACFs, exercise programs should provide continuous supervised moderate-intensity group exercise. For programs that mostly include independent ambulatory residents, exercise for at least 80 min per week should be provided. As many current residents are frail, tailored exercise is likely necessary and an individualised dose may be required. Future trials should test exercise interventions for less mobile residents.

UNASSIGNED: The study aimed to determine the test-retest reliability and concurrent validity of the Ratings of Perceived Stability (RPS) scale as a measure of balance exercise intensity in persons with multiple sclerosis (MS).
UNASSIGNED: Twenty participants with MS (mean age: 58.1 ± 15.29; 60% female) performed 14 balance tasks on two separate occasions wearing body-worn inertial sensors and rated their perceived stability for each task. Sensor data included sway velocity and angle, gait speed, turn velocity, and lean angle. Intraclass correlation coefficients (ICC) and Spearman rank correlations (rs) were employed to assess reliability and validity, respectively.
UNASSIGNED: The RPS showed good to excellent test-retest reliability (ICC> 0.75) on 12 out of the 14 tasks. The stability ratings revealed moderate relationships with postural sway outcomes in static balance tasks (rs: 0.49 to 0.77) and weak to moderate associations with gait speed (rs: -0.69 to -0.14). Ratings of stability were also strongly related to turn velocity (rs= -0.77) and moderately related to lean angle (rs= 0.58).
UNASSIGNED: The RPS scale offers a promising clinical tool to measure balance exercise intensity for persons with MS. This standardized scale allows for tailored balance training with a novel means for exercise monitoring and progression in this population.
The Ratings of Perceived Stability (RPS) scale is a reliable and valid measure for determining balance exercise intensity in persons with multiple sclerosis.The RPS scale can contribute to clear evaluation, description, and replication of balance training intensity in future balance interventions.

UNASSIGNED: Maintaining intrinsic articular cartilage homeostasis is essential for the health of cartilage. However, the impact of aerobic exercise of varying intensities on the articular cartilage homeostasis has never been studied. This study aims to elucidate the influence of different aerobic exercise intensities on the anabolic and catabolic processes within articular cartilage.
UNASSIGNED: Forty-eight male C57BL/6J mice, aged 7 weeks, were divided into 4 aerobic exercise groups and 1 control group. The aerobic exercise groups were subjected to both acute and chronic exercise protocols with varying intensities of 8, 12, 16, 20, and 24 m min-1. Total RNA from the knee joint cartilage was extracted in both phases to quantify mRNA of anabolic (Sox9, Col2a1, and Acan) and catabolic (MMP-13 and ADAMTS5) markers. In the chronic exercise, articular cartilage thickness and chondrocyte density were histologically assessed. Additionally, immunohistochemical staining quantified relevant molecules involved in cartilage metabolism.
UNASSIGNED: In the acute exercise, the 8 m min-1 group exhibited reduced ADAMTS5 expression compared to the control, 16 m min-1, and 24 m min-1 groups. Chronic exercise showed enhanced articular cartilage thickness in both the 8 and 12 m min-1 groups relative to the control group. Moreover, the 8 m min-1 group demonstrated elevated aggrecan levels in comparison to both the control and 24 m min-1 groups. Additionally, the 24 m min-1 group exhibited significantly higher ADAMTS5 levels than the control group.
UNASSIGNED: Our findings suggest that consistent low-intensity aerobic exercise suppresses catabolic molecule expression in articular cartilage, thereby fostering anabolic activity. Conversely, continuous high-intensity aerobic exercise can potentially disrupt cartilage homeostasis by enhancing catabolic processes. This dichotomy underscores the need for balanced exercise regimens to maintain cartilage health.

UNASSIGNED: The purpose of this study is to investigate changes in gut microbiota related to metabolic diseases after moderate and high-intensity exercise. A total of 24 participants were divided into three groups: Non-Exercise Group (NEG, n = 8, 28.6 ± 5.3 years, 176.0 ± 7.8 cm, 81.3 ± 14.6 kg), Moderate Intensity Exercise Group (MIEG, n = 8, 26.5 ± 3.3 years, 176.9 ± 5.0 cm, 75.4 ± 9.5 kg), and Vigorous Intensity Exercise Group (VIEG, n = 8, 30.6 ± 5.9 years, 174.2 ± 3.5 cm, 77.8 ± 12.2 kg).
UNASSIGNED: The participants were selected by assessing physical activity, gut health status, presence of diseases, recent disease diagnoses, and dietary disorders. Those who reported any presence disease or recent disease diagnosis were excluded from the current study. Stool samples were collected after a 10-h fast for gut microbiome analysis. MIEG participants trained at 40-59 % heart rate reserve (HRR) for at least 150 min per week, while VIEG participants trained at ≥ 60 % HRR for at least 90 min per week. After 4 weeks, all participants provided stool samples for gut microbiome analysis.Data analysis was conducted using the Wilcoxon test, with statistical significance set at ≤ 0.05.
UNASSIGNED: The results indicated an increase in Prevotella in MIEG, while Veillonella, Dorea_formicigenerans, and Dorea_longicatena exhibited a decrease (p < 0.05). In VIEG, there was an increase in Bacteroides, Butyricimonas, Odoribacter, and Alistipes (p < 0.05).
UNASSIGNED: These modified microbial groups were associated with factors related to metabolic diseases, including inflammatory bowel disease, obesity, colorectal cancer, diabetes, hypertension, metabolic liver diseases, and ischemic heart diseases. Additional research is essential to delve into the relationship between exercise and these alterations in the microbiome.

Antimicrobial peptides, key players of innate mucosal immunity in the oral cavity, exert antibacterial and bacteriolytic effects. This study aimed to clarify the effects of acute exercise at different intensities and durations on salivary antimicrobial peptide levels. In a randomized crossover trial, 14 young healthy untrained men performed intensity trials (cycling at 35%, 55%, and 75% of maximal oxygen uptake [VO2max] for 30 min) and duration trials (cycling at 55% VO2max for 30, 60, and 90 min). Saliva samples were collected at baseline and 0 and 60 min after exercise. In intensity trials, the change in salivary Lactoferrin levels from baseline to 0 min after 30-min exercise was greater at 75% VO2max exercise intensity compared to that at 35% VO2max. Furthermore, the change in salivary human beta defensin-2 (HBD-2) levels was greater at 75% VO2max compared to that at 35% and 55% VO2max. Salivary Lysozyme levels increased after exercise, independent of exercise intensity. However, salivary LL-37 levels did not change after exercise at any intensity. Additionally, in duration trials, the change in salivary levels of LL-37 and HBD-2 from baseline to 0 min after exercise at 55% VO2max was greater after 60 min and 90 min of exercise compared to that after 30 min of exercise. However, salivary Lactoferrin and Lysozyme levels increased after exercise, independent of exercise duration. Our findings suggest that secretory responses to acute exercise with exercise intensity and duration differ among salivary antimicrobial peptides.

BACKGROUND: Physical activity (PA) is essential for healthy aging, yet PA levels are low in older adults. Group-based nature programming may be an ideal opportunity for engaging older adults in PA and improving health-related quality of life.
METHODS: Twenty-seven older adults, 55-75 years of age (n = 14 active and n = 13 previously inactive), enrolled in a biweekly 8-week hiking program. At baseline, participants completed online questionnaires on health-related quality of life, behavioral and psychological outcomes, and a one-mile walk test to assess cardiorespiratory fitness.
RESULTS: Average attendance was 81% in the previously inactive groups and 74% in the active group. There was a significant increase in the physical component of quality of life over time in the previously inactive group (p = .03, d = 0.71). Participants significantly improved their cardiorespiratory fitness (p = .003, d = 0.77) and competency (p = .005, d = 0.41) as assessed by the Basic Psychological Needs for Exercise Scale. The previously inactive group additionally increased their self-efficacy for exercise (p = .001, d = 1.43). Both active and previously inactive groups exercised at a similar relative intensity during the hikes based on heart rate; however, perceived exertion at the end of the hike on average was lower among active participants (p = .014).
CONCLUSIONS: Group-based hiking for previously inactive older adults significantly improved physical health-related quality of life over an 8-week biweekly intervention. Hiking at an individualized pace may allow for hiking to be an appropriate PA program in previously inactive older adults.

Aerobic exercise with the correct intensity can attenuate motor and non-motor symptoms of Parkinson\'s disease (PD) and improve the quality of life. However, a specific, validated, non-invasive, and outside the laboratory protocol that assesses physiological variables to prescribe optimal aerobic exercise intensity for people with PD is nonexistent. Therefore, this study aimed to propose a protocol, the Parkinson\'s critical heart rate test (Parkinson-CHR test), to determine the critical heart rate (CHR) in individuals with PD and verify its validity, reliability, and sensitivity. Fifteen people with idiopathic PD, who were able to practice exercises, were recruited to participate in the study (71.1 ± 6.6 years). The study consisted of two experiments: i) the first one aimed to assess the validity and reliability of the protocol, with participants performing the test twice at a one-week interval; ii) the second experiment aimed to investigate the protocol sensitivity, with individuals being evaluated before and after an 8-week training program according to Parkinson-CHR intensity. In experiment 1, no differences between test and retest were observed in the time to cover the distances (400, 800 and 1200 m), the total heart rate, the critical heart rate, and critical speed (p > 0.05). In experiment 2, there was a reduction in time to cover 400 and 800 m as well as in the total heart rate for all distances after the 8-week training program. The Parkinson-CHR test is a reliable, reproducible, inexpensive, and non-invasive protocol to assess, prescribe, and monitor aerobic exercise intensity in people with PD.