(1) Background: Hydrogen (H₂) may be a potential therapeutic agent for managing Long COVID symptoms due to its antioxidant and anti-inflammatory properties. However, more scientific literature is needed to describe the effects of H₂ administration on treating symptoms. A study aimed to investigate the impact of hydrogen-rich water (HRW) administration on the fatigue and dyspnea of Long-COVID patients for 14 consecutive days. (2) Methods: In this randomized, single-blind, placebo-controlled study, 55 participants were recruited, and 23 of them were excluded. A total of 32 eligible participants were randomized into a hydrogen-rich water (HRW) group (n = 16) and a placebo water (PW) group (n = 16) in which they were instructed to consume hydrogen-rich water or placebo water for 14 days, respectively. The participants completed the Fatigue Severity Scale (FSS), Six-Minute Walk Test (6MWT), 30 s Chair Stand Test (30s-CST), Modified Medical Research Council Dyspnea Rating Scale (mMRC), Pittsburgh Sleep Quality Index (PSQI), and depression anxiety stress scale (DASS-21) before and after the intervention. A linear mixed-effects model was used to analyze the effects of HRW. Cohen’s d values were used to assess the effect size when significance was observed. The mean change with 95% confidence intervals (95% CI) was also reported. (3) Results: The effects of HRW on lowering FSS scores (p = 0.046, [95% CI = −20.607, −0.198, d = 0.696] and improving total distance in the 6WMT (p < 0.001, [95% CI = 41.972, 61.891], d = 1.010), total time for the 30s-CST (p = 0.002, [95% CI = 1.570, 6.314], d = 1.190), and PSQI scores (p = 0.012, [95% CI = −5.169, 0.742], d = 1.274) compared to PW were of a significantly moderate effect size, while there was no significant difference in mMRC score (p = 0.556) or DASS-21 score (p > 0.143). (4) Conclusions: This study demonstrates that HRW might be an effective strategy for alleviating fatigue and improving cardiorespiratory endurance, musculoskeletal function, and sleep quality. Still, it does not ameliorate dyspnea among Long-COVID patients.

Time-efficient strategies are needed to enhance physical fitness in sedentary university students. This pilot study examined the preliminary effects of maximal-effort stair-climbing exercise snacks performed alone (ESA) or combined with practical blood flow restriction (ES + BFR). Twenty-three sedentary male university students were included in the per-protocol analysis (ESA, n = 7; ES + BFR, n = 8; control, n = 8). Over 4 weeks, both intervention groups completed 48 supervised sessions, each consisting of three 20 s maximal stair climbs separated by 2 min rest. Assessed outcomes were forced vital capacity (FVC), 50 m sprint time, 1000 m run time, standing long jump (SLJ), sit-and-reach flexibility, and body mass index (BMI). Group × Time interactions were tested using mixed-model ANOVA. Significant interactions emerged for all metrics (p ≤ 0.01, partial η² = 0.35–0.70), except BMI. Both interventions significantly improved FVC, flexibility, 1000 m run and 50 m sprint performance (p < 0.05; absolute Cohen’s d range = 1.01–2.68). Although no significant between-group differences were observed, ES + BFR produced larger within-group effect sizes than ESA for 1000 m run time (d = −2.14 vs. −1.66) and 50 m sprint time (d = −2.21 vs. −1.89). Only ES + BFR significantly increased SLJ (p < 0.05), whereas the control group exhibited a significant decline (p < 0.05). BMI remained unchanged. The 4-week stair-climbing exercise snack protocol is feasible and may improve pulmonary function, endurance, speed, and flexibility in sedentary male students. Adding practical BFR shows promising numerical benefits for sprint, power, and endurance performance, but these exploratory findings require confirmation in larger trials.