Background: The coronavirus disease 2019 (COVID-19) pandemic has created challenges that have caused profound changes in health behaviors. This study aimed to explore how COVID-19 is affecting the health-related quality of life (QoL) among Chinese adults. Methods: The data of health-related behaviors and QoL were collected via online surveys from 2289 adults (mean age = 27.8 ± 12 years) who had been isolated at home for an average of 77 days. Results: More than 50% of the respondents reported that their time engaged in daily physical activity (PA) decreased, while sedentary behavior (SB) time increased compared with that before the lockdown. Only 20% of the respondents reported engaging in moderate-to-vigorous PA, 23% of adults reported changed their diets to be healthier, and 30% reported consuming more vegetables, fruits, and milk products than before home-isolation. During home-isolation, 75.2% of the adults rated their sleep quality as very good, and 65% reported that they were satisfied with their QoL. Sleep quality mediated the relationship between PA and QoL. Conclusion: The two-to-three-month home-isolation has had mixed effects on adult health behaviors in China. The participants were found to have focused more on their eating quality and patterns, which had a positive influence on their QoL. However, people should be encouraged to exercise at home with limited space to maintain a generally healthy lifestyle during a prolonged quarantine.

This study investigated the impact of Nordic walking on bone properties in postmenopausal women with pre-diabetes and non-alcohol fatty liver disease (NAFLD). A total of 63 eligible women randomly participated in the Nordic walking training (AEx, n = 33), or maintained their daily lifestyle (Con, n = 30) during intervention. Bone mineral content (BMC) and density (BMD) of whole body (WB), total femur (TF), femoral neck (FN), and lumbar spine (L2-4) were assessed by dual-energy X-ray absorptiometry. Serum osteocalcin, pentosidine, receptor activator of nuclear factor kappa-B ligand (RANKL) levels were analyzed by ELISA assay. After an 8.6-month intervention, the AEx group maintained their BMC_TF, BMD_TF, BMC_L2−4, and BMD_L2−4, and increased their BMC_FN (p = 0.016), while the Con group decreased their BMC_TF (p = 0.008), BMD_TF (p = 0.001), and BMD_L2−4 (p = 0.002). However, no significant group × time interaction was observed, except for BMD_L2−4 (p = 0.013). Decreased pentosidine was correlated with increased BMC_WB(r = −0.352, p = 0.019). The intervention has no significant effect on osteocalcin and RANKL. Changing of bone mass was associated with changing of pentosidine, but not with osteocalcin and RANKL. Our results suggest that Nordic walking is effective in preventing bone loss among postmenopausal women with pre-diabetes and NAFLD.

Background: Healthcare workers rank among the groups that are most vulnerable to the SARS-CoV-2 infection. Deterioration in physical fitness and mental health is a common manifestation in the post-COVID-19 person, which require specific and effective treatment. This study aimed to evaluate the effects of a 6-week, semi-supervised exercise intervention on physical fitness and mental health in post-COVID-19 healthcare workers (HCWs). Methods: Fifty-four HCWs infected with SARS-CoV-2 within 3–4 weeks were randomly assigned to an exercise group or a control group. The exercise group followed a 6-week semi-supervised program with three weekly 60–80-minute sessions. Assessments included handgrip strength, sit-to-stand, push-up, curl-up, cardiorespiratory fitness, flexibility, balance, and mental health. Analyses followed intention-to-treat principles. Results: Compared with those of the control group, the push-up scores (p = 0.003, η_p ² = 0.162), curl-up scores (p < 0.001, η_p ² = 0.248), and maximum load of the rowing ergometer (p = 0.012, η_p ² = 0.121) significantly increased in the exercise group. The depression (p = 0.003) and anxiety (p = 0.023) scores significantly decreased at the end of the intervention in the exercise group, although no significant differences were observed between the groups. No adverse events potentially linked to the intervention were observed. Conclusions: A six-week semi-supervised exercise training significantly improved functional muscle strength and endurance, and maximum rowing intensity in post-COVID-19 HCWs compared to controls, along with within-group reductions in depression and anxiety. No adverse events were reported. These findings suggest that exercise may be a safe and effective recovery strategy to prevent or alleviate post-COVID-19 conditions, although further research is needed to confirm long-term effectiveness and mechanisms of action. Trial registration: The study was registered in the Chinese Clinical Trial Registry (#ChiCTR2100051901) from 2021-10-09.

Background: How bone properties would change after exercise intervention in patients with comorbidities are largely unknown. This study investigated the impact of Nordic walking on bone properties in postmenopausal women with pre-diabetes and non-alcohol fatty liver disease (NAFLD).Methods: The study is a part of a large randomized controlled trial. Of the eligible participants, 63 postmenopausal women (aged 50-65 years) with prediabetes and NAFLD participated in either a progressive supervised Nordic walking training (60-75% VO2max intensity), 2-3 times/week, 30-60 min/sessions for 8.6-month (AEx, n=33), or maintained their daily lifestyle during intervention (Con, n=30). Bone mineral content (BMC) and density (BMD) of the whole body (WB), total femur (TF), femoral neck (FN) and lumbar spine (L2-4) were assessed by a dual-energy X-ray absorptiometry. Venous blood samples were analyzed for serum osteocalcin, pentosidine and receptor activator of nuclear factor kappa-B ligand (RANKL) levels by ELISA assay. Results: After 8.6-month intervention, the AEx group maintained their BMC_TF, BMD_TF, BMC_L2-4 and BMD_L2-4, and increased their BMC_FN (p<0.016), while the Con group decreased their BMC_TF (p<0.008), BMD_TF (p<0.001)) and BMD_L2-4 (p<0.002). However, no significant group × time interaction was observed, except for BMD_L2-4 (p=0.013). Decreased pentosidine was correlated with increased BMC_WB (=-0.352, p=0.019). The intervention has no significant effect on osteocalcin and RANKL. Conclusions: Our results suggest that Nordic walking is effective in preventing bone loss among postmenopausal women with pre-diabetes and NAFLD. Changing of bone mass is associated with changing of pentosidine. However, this effect is not associated with osteocalcin and RANKL.Trial registration: ISRCTN registry, ISRCTN 42622771, registered 23 April 2013, https://www.isrctn.com/

Background: Metabolic prediction equations provide a low-cost means of estimating submaximal cycling oxygen uptake (VO₂), yet equations derived from maximal exercise are often applied to steady-state fixed-load protocols without validation. Portable analysers including the COSMED K5 and CORTEX MetaMax 3B permit field-based VO₂ measurement, but neither is error-free. We assessed agreement between four prediction equations and both devices in untrained young women, partitioning total error into bias-related and residual components. Methods: Nineteen untrained young women completed four constant-power cycling stages (30, 40, 50, 60 W). VO₂ was estimated from four equations (one submaximal cycling formula, three maximal-test equations) and measured concurrently with two portable indirect calorimeters. Linear mixed-effects models accounted for repeated within-participant observations. Agreement was evaluated using Lin’s concordance correlation coefficient (CCC), mean absolute percentage error (MAPE) and Bland–Altman analysis with proportional bias testing; 95% confidence intervals came from participant-level cluster bootstrap, with false discovery rate correction. Results: Every equation–device combination showed significant negative bias (all P < 0.01), and underprediction worsened at higher intensities. The ACSM submaximal equation with CORTEX MetaMax 3B showed the closest agreement (CCC = 0.69, MAPE = 12.9%, bias = − 1.71 mL·kg⁻¹·min⁻¹), with residual error accounting for 68.5% of total disagreement. The three maximal-test equations paired with COSMED K5 yielded the largest errors, 83–91% of which was bias-related. Even the best combination showed growing underprediction as power increased. Conclusions: The ACSM submaximal cycling equation showed the closest relative agreement among the eight tested pairings. Maximal-test equations agreed poorly with device-measured values during low-to-moderate fixed-load cycling. Without a laboratory gold standard, these findings reflect relative cross-device agreement rather than absolute accuracy, and disagreement cannot be attributed solely to equation error. The intensity-dependent bias suggests that a universal correction factor would be inadequate under the tested conditions. Any correction approach would require population- and device-specific external validation before clinical use.