We aimed to evaluate the effects of the COVID-19 lock down on lifestyle in China during the initial stage of the pandemic. A questionnaire was distributed to Chinese adults living in 31 provinces of China via the internet using a snowball sampling strategy. Information on 7-day physical activity recall, screen time, and emotional state were collected between January 24 and February 2, 2020. ANOVA, χ² test, and Spearman’s correlation coefficients were used for statistical analysis. 12,107 participants aged 18–80 years were included. During the initial phase of the COVID-19 outbreak, nearly 60% of Chinese adults had inadequate physical activity (95% CI 56.6%–58.3%), which was more than twice the global prevalence (27.5%, 25.0%–32.2%). Their mean screen time was more than 4 hours per day while staying at home (261.3 ± 189.8 min per day), and the longest screen time was found in young adults (305.6 ± 217.5 min per day). We found a positive and significant correlation between provincial proportions of confirmed COVID-19 cases and negative affect scores (r = 0.501, p = 0.004). Individuals with vigorous physical activity appeared to have a better emotional state and less screen time than those with light physical activity. During this nationwide lockdown, more than half of Chinese adults temporarily adopted a sedentary lifestyle with insufficient physical activity, more screen time, and poor emotional state, which may carry considerable health risks. Promotion of home-based self-exercise can potentially help improve health and wellness.

Background: To assess the effects of resistance training on circulating irisin concentration in older adults, and to determine the association between resistance training induced alteration of irisin and body fat. Methods: Seventeen older adults (mean age is 62.1 years old) were randomized into old control group (male, n=7), and old training group (male, n=10). The control group has no any exercise intervention. The resistance training group underwent leg muscle strength and core strength training program 2 times/wk, 55 min/class for 12 weeks. Before and after the intervention, we evaluated serum irisin level and body composition. Results: Serum irisin level was significantly increased in the resistance training group after the intervention period (P < 0.01), but not in the control group. In the resistance training group, the reduction in whole-body fat percent was negatively correlated with the change in serum irisin level (r = −0.705, P < 0.05). Conclusion: After the 12 weeks intervention, circulating irisin levels were significantly elevated in the older adults. These results suggest a possible role for secreted irisin in the resistance exercise-induced alteration of body fat in older adults.

This study aimed to explore a valid test protocol for measuring VO_2max in healthy untrained male Wistar rats of different ages and quantifying the exercise intensity (%VO_2max) of running under different treadmill grades and speeds. The test protocols and %VO_2max will provide a reference for the design of exercise intensity. We tested male Wistar rats aged 4 weeks, 10 weeks, 10 months and 16 months old with three test protocols (Procedure 1 [P1], 2 [P2] and 3 [P3]) for each age group to quantify VO_2max. We analysed VO_2max, respiratory exchange ratio and test duration to determine an optimal test protocol of VO_2max for different age groups. We used the optimal test protocol to explore the changes in age-related VO_2max. Finally, %VO_2max of running under different treadmill speeds and grades was quantified. VO_2max of Wistar rats decreased significantly after the age of 4 weeks (p < 0.05). The optimum VO_2max can be induced by personalised protocols for different ages. In 4-week-old Wistar rats, the highest VO_2max values were attained by P1 (104.4 ± 6.9 mL · kg⁻¹ · min⁻¹, p = 0.032). The highest VO_2max value (84.7 ± 3.7 mL · kg⁻¹ · min⁻¹, p = 0.037) of 8-week-old Wistar rats was attained in P2. In 10-month-old Wistar rats, the highest VO_2max value was obtained in P3 (63.3 ± 1.7 mL · kg⁻¹ · min⁻¹). This work could be used as a reference for assessing aerobic capacity in studies on exercise intervention with untrained male Wistar rats. However, the %VO_2max measurements at various treadmill speeds and grades only apply to untrained male Wistar rats.

Background: Endurance exercise is known to promote a substantial effect on the energy balance in rats and humans. However, little is known about the exact mechanisms for the appetite-suppressive effects of endurance exercise. We hypothesized that endurance training might activate signaling cascades in the hypothalamus known to be involved in leptin signaling. Methods: 16 male Wistar rats were randomly assigned to two groups: sedentary (n = 8) and exercise groups (n = 8). Animals in the exercise group started treadmill running at 30 m/min, 0% grade, for 1 min/bout. Running time was gradually increased by 2 min/bout every day. The training plan was one bout per day during initial two weeks, and two bouts per day during 3rd-9th week. At the end of nine-week experiment, blood was analyzed for low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), total cholesterol (TC), free fatty acid (FFA), interleukin (IL)-6, and leptin in both groups. Activations of janus kinase 2-signaling transducer and activator of transcription 3 (JAK2-STAT3), protein kinase B (Akt), extracellular regulated kninase (ERKs), and suppressor of cytokine signaling 3 (SOCS3) in hypothalamus were measured in the end of nine weeks of exercise protocol. Results: Nine-week endurance exercise induced lower concentrations of LDL-C, TG, TC, FFA, and leptin in rats (P < 0.05 or P < 0.01). Nine-week endurance exercise significantly increased the circulating IL-6 concentration compared with sedentary group (239.6 ± 37.2 pg/ml vs. 151.8 ± 31.5 pg/ml, P < 0.01). Exercise rats showed significant increases in JAK2, STAT3, Akt, ERKs, and SOCS3 phosphorylations compared with sedentary rats (P < 0.01). Conclusion: The data suggest that endurance exercise is a leptin signaling mimetic in hypothalamus of Wistar rats.

Background: The pandemic of 2019 novel coronavirus (COVID-19) poses a challenge to health promotion in the days of lockdown. We aimed to evaluate the characteristics of lifestyle in China during the initial stage of COVID-19 lock down. Methods: The questionnaire was distributed to Chinese adults living in 31 provinces of China via internet using a snowball sampling strategy. Information on 7-day physical activity recall, sedentary screen time, and emotional state were collected between January 24 and February 2, 2020. ANOVA, χ² test, and spearman’s correlation coefficient were used for statistical analysis. Findings: 12107 participants aged 18-80 years old were included. During the initial phase of COVID-19 outbreak, nearly 60% of Chinese adults had inadequate physical activity (95% CI 56.6%-58.3%), which was more than twice the global prevalence (27·5%, 25·0–32·2%). Their mean screen time was more than 4 hours per day during home stay (261·3 ± 189·8 minutes per day). Of all participants, the positive affect score was 24·78 and the negative affect score was 19·34. In addition, we found that the proportions of confirmed COVID-9 cases were positively and significantly correlated with provincial negative affect scores (r=0·501, p =0·004) but not correlated with the prevalence of insufficient physical activity, screen time, and positive scores ( p >0·05). Individuals with vigorous physical activity appeared to have better emotional state and less sedentary screen time than those with light physical activity. Interpretation: During this nationwide lockdown, more than half of Chinese adults were temporarily living in a sedentary lifestyle with insufficient physical activity, more screen time, and poor emotion states, which may carry considerable health risks. Promotion of home-based self-exercise can potentially help improve health and wellness. Funding Statement: This study was funded by the National Key Technology R&D Program (2019YFF0301600), and the National Natural Science Foundation of China (31371195 and 11775059). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: Full ethical approval was obtained from the China Institute of Sport Science, Beijing, China (CISS-2020-01-28). All participants gave their informed consent.