This study aimed to systematically review the exercise intensities associated with various physical activities, synthesize the physiological effects induced by different intensity levels, and establish a dose-response reference guide for exercise modalities, thereby providing a foundation for precision-based fitness regimens. Methods: A comprehensive literature search was conducted across PubMed, Cochrane, Embase, Web of Science, EBSCO, CNKI, VIP, and Wanfang databases to identify studies examining the effects of exercise modalities on physiological indicators. The methodological quality of included randomized controlled trials (RCTs) was assessed using the Cochrane 5.1 handbook criteria. Effect sizes were pooled, and subgroup analyses were performed using Review Manager 5.4. Results: A total of 42 RCT studies were included. Lowintensity exercise modalities included ordinary walking, stair climbing, and Pilates. Moderate-intensity exercise modalities included brisk walking, Baduanjin, jogging, square dancing, Tai Chi, swimming, cycling, and dancing. High-intensity exercises included fast walking, fast running, soccer, and yoga. Low-intensity exercises improved HDL-C (d=0.06), resting heart rate (d=-2.98), and diastolic blood pressure (d=-2.93). Moderate- intensity exercises improved TG (d=-0.21), TC (d=-0.32), HDL-C (d=0.09), resting heart rate (d=-4.22), systolic blood pressure (d=-4.92), diastolic blood pressure (d=-3.51), weight (d=-2.46), and vital capacity (d=271.03). High-intensity exercises improved blood glucose (d=-0.18), systolic blood pressure (d=-3.21), and diastolic blood pressure (d=-2.58). Traditional Chinese exercises improved HDL-C (d=0.19), blood glucose (d=-1.49), vital capacity (d=285.09), systolic blood pressure (d=-9.96), and diastolic blood pressure (d=- 5.68). Common exercises improved TG (d=-0.18), TC (d=-0.18), HDL-C (d=0.08), vital capacity (d=223.62), resting heart rate (d=-3.51), systolic blood pressure (d=-4.90), diastolic blood pressure (d=-2.96), weight (d=- 2.04), and BMI (d=-0.74). Conclusion: Moderate-intensity exercises (e.g., brisk walking, jogging, swimming, Tai Chi) yielded more comprehensive physiological improvements compared to other intensities. Traditional Chinese exercises exhibited superior efficacy in optimizing HDL-C, glucose metabolism, respiratory function, and blood pressure regulation.

Background/Objectives: Global population aging is associated with a rising prevalence of malnutrition among adults aged ≥80 years. Gut dysbiosis is linked to immune decline and impaired nutrient absorption, and aerobic exercise may enhance microbial diversity. This study investigated gut microbiota changes after a 12-week aerobic exercise intervention in octogenarians stratified by nutritional status. Methods: A total of 129 nursing home residents (≥80 years) were classified via the Mini Nutritional Assessment Short-Form (MNA-SF) into a healthy group (HG, MNA-SF ≥ 11) and a malnourished group (MG, MNA-SF < 11). Both groups underwent a 12-week brisk walking intervention (three sessions/week, 1 h/session, 40–60% heart rate reserve). Fecal samples were collected at baseline and post-intervention and were analyzed via shotgun metagenomic sequencing. Results: A total of 36 participants completed the intervention (HG = 17, MG = 19). Within-group baseline-to-post-intervention analysis showed no significant changes in alpha or beta diversity in the MG. However, post-intervention between-group comparison revealed higher microbial richness and diversity in the MG vs. the HG, with enrichment of taxa including Faecalibacterium prausnitzii and Streptococcus salivarius. Functional analysis revealed significant enhancements in metabolic pathways related to amino acid biosynthesis, protein synthesis, and quorum sensing in the MG. In contrast, the HG showed limited shifts in microbial diversity but an increase in species involved in carbohydrate metabolism. Conclusions: After 12 weeks, the malnourished group showed higher post-intervention microbial richness and diversity than the healthy group, with differences in taxonomic and predicted functional profiles. Without a non-intervention control group, the microbiota differences observed during the 12-week aerobic exercise period can only be considered observational associations, not causal. Additionally, the high dropout rate (72.1%) limits the generalizability of the findings. Clinical trial registration: The Chinese Clinical Trial Registry on 19 October 2022 (ChiCTR2200064801).

Background: Multidimensional evidence on exercise participation and frailty in older adults is limited. Methods: This 12-week preference-based, non-randomized study included 145 participants (mean age 82.25 years): walking (n = 50), resistance training (n = 20), Traditional Chinese exercise (n = 23), and control (n = 52). Frailty was the primary outcome; physical-performance and molecular analyses were exploratory. Paired trajectories, baseline-stratified binary transitions, and adjusted associations were examined. Results: Among paired participants, pre-frailty/frailty prevalence changed from 70.0% to 60.0% with walking, 90.0% to 70.0% with resistance training, 50.0% to 63.6% with Traditional Chinese exercise (n = 22), and 50.0% to 69.2% in controls. Baseline status constrained opportunities for binary improvement or deterioration. All adjusted frailty risk-ratio confidence intervals included 1. Walking was associated with faster Timed Up and Go and Five-Yard Walk Test performance after correction across eight outcomes. Molecular changes also occurred in controls; intervention timing and potential laboratory-batch confounding limited between-group interpretation. No microbiome taxon survived multiplicity correction; small paired samples limited precision. Conclusions: Walking and resistance-training groups showed descriptively more favorable prevalence trajectories, but adjusted frailty comparisons remained inconclusive. These findings do not establish frailty prevention, modality superiority, or exercise-specific molecular mechanisms.

Background: Physical fitness is important for health and independence in older adults, but existing systems do not always provide a continuous multidomain score. Objective: To develop and preliminarily evaluate a Physical Fitness Index (PFI) for older adults in a Chinese retirement community. Methods: A total of 561 participants aged 65–89 years completed assessments of body composition, strength, endurance, balance, mobility, and flexibility. Scores were normalized within sex and 5-year age groups and combined using a fixed radar-axis order. Results: The PFI averaged 39.24 ± 13.43 points (range, 4.16–84.47). In a reduced surrogate regression model, R² was 0.825 and ten-fold cross-validation yielded an RMSE of 5.79 points and an MAE of 4.33 points. Conclusion: The PFI provides a continuous overall score with a domain profile, but its calibration and measurement properties require external and longitudinal validation.