ObjectiveTo explore the effects and mechanism of the modified Danggui Yinzi on "itch-anxiety" model rats of chronic urticaria （CU）. MethodsThe 36 SPF-grade 6-8-week-old female SD rats were randomly divided into a blank control group，a model group，a positive control group，a low-dose modified Danggui Yinzi group，a medium-dose modified Danggui Yinzi group，and a high-dose modified Danggui Yinzi group. A "itch-anxiety" model was established by intraperitoneal injection of a suspension of sodium chloride and aluminum hydroxide and ovalbumin，combined with chronic unpredictable emotional stress stimulation. After successful modeling，rats in each group were administered drugs by gavage. The positive control group was given intragastric administration of the drug solutions of cetirizine and fluoxetine （2.08 mg·kg^-1·d^-1 fluoxetine， 2 mg·kg^-1·d^-1 cetirizine）， the low-，medium-，and high-dose modified Danggui Yinzi groups were administered traditional Chinese medicine at 1.44，2.88， 5.76 g·kg^-1， respectively，while the blank control group and model group were given an equal volume of normal saline. All interventions lasted for 15 days. Behavioral changes were evaluated by the elevated plus-maze test （detecting the percentage of entries into the open arms （OE%），the percentage of time spent in the open arms （OT%），and the total number of entries into the open and closed arms （TNE）），the open-field test （detecting total activity，average movement speed，and latency to enter the central area），and scratching behavior observation. Pathological changes of skin tissues were observed by hematoxylin-eosin （HE） staining and toluidine blue staining，while those of amygdala tissues were observed by HE staining，Nissl staining，and immunofluorescence detection of ionized calcium-binding adapter molecule-1 （Iba-1）. The content of immunoglobulin E （IgE），interleukin-33 （IL-33），histamine in serum and glutamate in the amygdala was detected by enzyme-linked immunosorbent assay （ELISA）. Western blot was used to detect the protein expression of striatal-enriched protein tyrosine phosphatase （STEP），N-methyl-D-aspartate receptor subunit 2B （NR2B）， calmodulin-dependent protein kinase Ⅱ （CaMKⅡ），phosphorylated CaMKⅡ （p-CaMKⅡ），mitogen-activated protein kinase （MAPK），phosphorylated MAPK （p-MAPK），nuclear factor kappa-light-chain-enhancer of activated B cells （NF-κB），phosphorylated NF-κB （p-NF-κB），and postsynaptic density protein-95 （PSD-95） in the amygdala. ResultsCompared with the blank control group，the model group rats showed obvious anxiety-like behaviors （decreased OE%，OT%，and TNE，reduced total activity，slower average movement speed，and prolonged latency to enter the central area），increased scratching times，obvious skin inflammation and mast cell degranulation，severe amygdala tissue damage，increased glutamate content in the amygdala，and elevated levels of IgE and IL-33 in serum. The expression of STEP，NF-κB，p-NF-κB，NR2B，MAPK，p-MAPK，CaMKⅡ，and p-CaMKⅡ proteins in the amygdala increased，while the expression of PSD-95 protein decreased （P<0.05）. Compared with the model group，the modified Danggui Yinzi group of each dose had increased OE%，OT%，TNE，total activity，and average movement speed，shortened latency to enter the central area， reduced scratching times，alleviated skin inflammation and mast cell degranulation，relieved amygdala tissue damage，decreased glutamate content in the amygdala，and reduced levels of IgE and IL-33 in serum. Moreover，compared with the model group，the low -，medium-，and high-dose modified Danggui Yinzi groups showed decreased expression levels of STEP，NF-κB，p-NF-κB，NR2B，MAPK，p-MAPK，CaMKⅡ，and p-CaMKⅡ proteins in the amygdala，and increased expression of PSD-95 protein. There was a significant dose-effect relationship，with the high-dose group showing the most significant regulatory effect （P<0.05）. ConclusionThe modified Danggui Yinzi has a therapeutic effect on "itch-anxiety" model rats of CU. Its mechanism may be related to regulating glutamate metabolism in the amygdala，modulating the STEP/NR2B/CaMKⅡ/MAPK/NF-κB pathway，and regulating the expression of PSD-95.

ObjectiveTo characterize the evidence distribution and methodological quality of randomized controlled trials （RCTs） on oral Chinese herbal medicine （CHM） for atopic dermatitis （AD） based on evidence mapping. MethodsSeven databases （CNKI， Wanfang Data， VIP， CBM， Cochrane Library， PubMed， and Embase） and the Chinese Clinical Trial Registry were searched for the RCTs in Chinese and English. Evidence distribution was presented graphically and textually， and methodological quality was assessed via the Cochrane Risk of Bias tool （ROB 1.0）. ResultsA total of 168 RCTs were included. The number of annual publications showing an increasing trend， and 72.6% RCTs had sample sizes of 51-100 participants. The studies evaluated 108 distinct CHM interventions categorized as decoctions， granules， Chinese patent medicines， and extracts. Compound Glycyrrhizin was the most frequently used， followed by Xiaofengsan and Chushi Weiling decoction. Among the RCTs， 57.1% had the treatment courses of 4-8 weeks. Outcome measures predominantly focused on clinical response rate， skin lesion severity scores， and adverse events， with less attention to TCM symptom scores， skin barrier function， and relapse rates. The overall risk of bias was generally high. ConclusionWhile CHM for AD is a research hotspot and demonstrates clinical advantages， the related studies have problems such as unclear clinical positioning， poor research standardization and methodological quality， and insufficient prominence of TCM clinical advantages. Large-sample， methodologically rigorous， and high-quality studies are needed to enhance the evidence base for CHM in treating AD.

ObjectiveTo characterize the evidence distribution and methodological quality of randomized controlled trials （RCTs） on oral Chinese herbal medicine （CHM） for atopic dermatitis （AD） based on evidence mapping. MethodsSeven databases （CNKI， Wanfang Data， VIP， CBM， Cochrane Library， PubMed， and Embase） and the Chinese Clinical Trial Registry were searched for the RCTs in Chinese and English. Evidence distribution was presented graphically and textually， and methodological quality was assessed via the Cochrane Risk of Bias tool （ROB 1.0）. ResultsA total of 168 RCTs were included. The number of annual publications showing an increasing trend， and 72.6% RCTs had sample sizes of 51-100 participants. The studies evaluated 108 distinct CHM interventions categorized as decoctions， granules， Chinese patent medicines， and extracts. Compound Glycyrrhizin was the most frequently used， followed by Xiaofengsan and Chushi Weiling decoction. Among the RCTs， 57.1% had the treatment courses of 4-8 weeks. Outcome measures predominantly focused on clinical response rate， skin lesion severity scores， and adverse events， with less attention to TCM symptom scores， skin barrier function， and relapse rates. The overall risk of bias was generally high. ConclusionWhile CHM for AD is a research hotspot and demonstrates clinical advantages， the related studies have problems such as unclear clinical positioning， poor research standardization and methodological quality， and insufficient prominence of TCM clinical advantages. Large-sample， methodologically rigorous， and high-quality studies are needed to enhance the evidence base for CHM in treating AD.

ObjectiveTo investigate the ameliorative effect of Xingpi capsules on functional dyspepsia（FD） and the potential mechanism. MethodsSixty SPF-grade male SD neonatal rats（7 days old） were randomly divided into the normal group（n=12） and the modeling group（n=48）， and the FD model was prepared by iodoacetamide gavage in the modeling group. After the model was successfully prepared， the rats in the modeling group were randomly divided into the model group， the low-dose and high-dose groups of Xingpi capsules（0.135， 0.54 g·kg^-1） and the domperidone group（3 mg·kg^-1）， with 12 rats in each group. Rats in the normal and model groups were gavaged with distilled water， and rats in the rest of the groups were gavaged with the corresponding medicinal solution， once a day for 7 d. The general survival condition of the rats was observed， and the water intake and food intake of the rats were measured， the gastric emptying rate and the small intestinal propulsion rate were measured at the end of the treatment， the pathological damage of the rat duodenum was examined by hematoxylin-eosin（HE） staining， and the expressions of colonic tight junction protein（Occludin） and zonula occludens protein-1（ZO-1） were detected by immunofluorescence. The differentially expressed genes in the duodenal tissues of the model group and the normal group， and the high-dose group of Xingpi capsules and the model group were detected by transcriptome sequencing after the final administration， and Gene Ontology（GO） and Kyoto Encyclopedia of Genes and Genomes（KEGG） enrichment analyses were carried out. The transcriptomic results were validated by Western blot， immunofluorescence， and real-time fluorescence quantitative polymerase chain reaction（Real-time PCR）， and the active ingredients of Xingpi capsules were screened for molecular docking with the key targets. ResultsCompared with the normal group， the general survival condition of rats in the model group was poorer， and the water intake， food intake， gastric emptying rate and small intestinal propulsion rate were all significantly reduced（P<0.05）， inflammatory infiltration was seen in duodenal pathology， and the fluorescence intensities of Occludin and ZO-1 in the colon were significantly reduced（P<0.01）. Compared with the model group， the general survival condition of rats in the high-dose group of Xingpi capsules improved significantly， and the water intake， food intake， gastric emptying rate and small intestinal propulsion rate were all significantly increased（P<0.05）， the duodenal pathology showed a decrease in inflammatory infiltration， and the fluorescence intensities of colonic Occludin and ZO-1 were significantly increased（P<0.01）. Transcriptomic results showed that Xingpi capsules might exert therapeutic effects by regulating the phosphatidylinositol 3-kinase（PI3K）/protein kinase B（Akt） through the key genes such as Slc5a1， Abhd6. The validation results showed that compared with the normal group， the phosphorylation levels of PI3K and Akt proteins， the protein expression level of interleukin（IL）-1β， and the fluorescence intensities of IL-6 and IL-1β were significantly increased in the model group（P<0.05， P<0.01）， and the mRNA levels of Slc5a1， Abhd6， Mgam， Atp1a1， Slc7a8， Cdr2， Chrm3， Slc5a9 and other key genes were significantly increased（P<0.01）. Compared with the model group， the phosphorylation levels of PI3K and Akt， the protein expression level of IL-1β and the fluorescence intensities of IL-6 and IL-1β in the high-dose group of Xingpi capsules were significantly reduced（P<0.05， P<0.01）， and the mRNA levels of Slc5a1， Abhd6， Mgam， Atp1a1， Slc7a8， Cdr2， Chrm3 and Slc5a9 were significantly reduced（P<0.05）. Weighted gene co-expression network analysis and molecular docking results showed that E-nerolidol and Z-nerolidol in Xingpi capsules were well bound to ABDH6 protein， and linarionoside A， valerosidatum and senkirkine were well bound to Slc5a1 protein. ConclusionXingpi capsules can effectively improve the general survival and gastrointestinal motility of FD rats， its specific mechanism may be related to the inhibition of PI3K/Akt signaling pathway to alleviate the low-grade inflammation of duodenum， and E-nerolidol， Z-nerolidol， linarionoside A， valerosidatum and senkirkine may be its key active ingredients.

ObjectiveTo investigate the ameliorative effect of Xingpi capsules on functional dyspepsia（FD） and the potential mechanism. MethodsSixty SPF-grade male SD neonatal rats（7 days old） were randomly divided into the normal group（n=12） and the modeling group（n=48）， and the FD model was prepared by iodoacetamide gavage in the modeling group. After the model was successfully prepared， the rats in the modeling group were randomly divided into the model group， the low-dose and high-dose groups of Xingpi capsules（0.135， 0.54 g·kg^-1） and the domperidone group（3 mg·kg^-1）， with 12 rats in each group. Rats in the normal and model groups were gavaged with distilled water， and rats in the rest of the groups were gavaged with the corresponding medicinal solution， once a day for 7 d. The general survival condition of the rats was observed， and the water intake and food intake of the rats were measured， the gastric emptying rate and the small intestinal propulsion rate were measured at the end of the treatment， the pathological damage of the rat duodenum was examined by hematoxylin-eosin（HE） staining， and the expressions of colonic tight junction protein（Occludin） and zonula occludens protein-1（ZO-1） were detected by immunofluorescence. The differentially expressed genes in the duodenal tissues of the model group and the normal group， and the high-dose group of Xingpi capsules and the model group were detected by transcriptome sequencing after the final administration， and Gene Ontology（GO） and Kyoto Encyclopedia of Genes and Genomes（KEGG） enrichment analyses were carried out. The transcriptomic results were validated by Western blot， immunofluorescence， and real-time fluorescence quantitative polymerase chain reaction（Real-time PCR）， and the active ingredients of Xingpi capsules were screened for molecular docking with the key targets. ResultsCompared with the normal group， the general survival condition of rats in the model group was poorer， and the water intake， food intake， gastric emptying rate and small intestinal propulsion rate were all significantly reduced（P<0.05）， inflammatory infiltration was seen in duodenal pathology， and the fluorescence intensities of Occludin and ZO-1 in the colon were significantly reduced（P<0.01）. Compared with the model group， the general survival condition of rats in the high-dose group of Xingpi capsules improved significantly， and the water intake， food intake， gastric emptying rate and small intestinal propulsion rate were all significantly increased（P<0.05）， the duodenal pathology showed a decrease in inflammatory infiltration， and the fluorescence intensities of colonic Occludin and ZO-1 were significantly increased（P<0.01）. Transcriptomic results showed that Xingpi capsules might exert therapeutic effects by regulating the phosphatidylinositol 3-kinase（PI3K）/protein kinase B（Akt） through the key genes such as Slc5a1， Abhd6. The validation results showed that compared with the normal group， the phosphorylation levels of PI3K and Akt proteins， the protein expression level of interleukin（IL）-1β， and the fluorescence intensities of IL-6 and IL-1β were significantly increased in the model group（P<0.05， P<0.01）， and the mRNA levels of Slc5a1， Abhd6， Mgam， Atp1a1， Slc7a8， Cdr2， Chrm3， Slc5a9 and other key genes were significantly increased（P<0.01）. Compared with the model group， the phosphorylation levels of PI3K and Akt， the protein expression level of IL-1β and the fluorescence intensities of IL-6 and IL-1β in the high-dose group of Xingpi capsules were significantly reduced（P<0.05， P<0.01）， and the mRNA levels of Slc5a1， Abhd6， Mgam， Atp1a1， Slc7a8， Cdr2， Chrm3 and Slc5a9 were significantly reduced（P<0.05）. Weighted gene co-expression network analysis and molecular docking results showed that E-nerolidol and Z-nerolidol in Xingpi capsules were well bound to ABDH6 protein， and linarionoside A， valerosidatum and senkirkine were well bound to Slc5a1 protein. ConclusionXingpi capsules can effectively improve the general survival and gastrointestinal motility of FD rats， its specific mechanism may be related to the inhibition of PI3K/Akt signaling pathway to alleviate the low-grade inflammation of duodenum， and E-nerolidol， Z-nerolidol， linarionoside A， valerosidatum and senkirkine may be its key active ingredients.

OBJECTIVE:High-intensity interval training(HIIT)and moderate-intensity continuous training(MICT)can improve the quality of life of patients with clinical chronic diseases,but their application effects and regulatory factors in adults with insufficient physical activity are still unclear.This study aimed to explore the application effects and regulatory factors of HIIT and MICT on the quality of life of adults with insufficient physical activity. METHODS:A systematic literature search was conducted in databases including Web of Science Core Collection,Medline(EBSCO Host),PubMed,and Cochrane Library.The search time limit was from the establishment of each database to September 2023.The types of included literature were randomized controlled trials,and the research subjects were physically inactive adults.RevMan 5.4 software and the GRADE evidence evaluation framework were used to assess the quality of the included literature.Main effects pooling of random effects models was performed using R Studio(version 4.2.0).Subgroup analyses,regression analyses,and sensitivity analyzes were used to explore the sources of study heterogeneity and moderators. RESULTS:(1)Thirty-two randomized controlled trials of moderate to high quality were included,involving 2 083 physically inactive adults(HIIT group n=474;MICT group n=708;control group n=901).(2)Compared with the non-training control group,HIIT[Hedges'g=0.61;95%confidence interval(CI):0.40-0.83;I2=45%]and MICT(Hedges'g=0.66;95%CI:0.25-1.08;I2=89%)significantly improved the quality of life.Direct comparison studies of HIIT and MICT found no significant differences in the quality of life(Hedges'g=-0.01;95%CI:-0.23-0.21;I2=0%).(3)Subgroup analysis showed that HIIT and MICT were more effective in improving the physical components of the quality of life(HIIT:Hedges'g=0.82 vs.0.75;MICT:Hedges'g=0.74 vs.0.55),while cycling had a better trend in improving overall quality of life(HIIT:Hedges'g=0.74 vs.0.36;MICT:Hedges'g=1.08 vs.0.52).(4)Additionally,regression analysis did not identify any significant moderators(P>0.05 for all factors).(5)None of the above meta-analyses found publication bias(Egger test P>0.05). CONCLUSION:(1)Moderate to high level evidence shows that both HIIT and MICT can improve the quality of life of adults with insufficient physical activity,and the intervention effects between the two are similar.Therefore,when choosing between these two options,it is necessary to comprehensively consider factors such as time economy,scheduling flexibility,and application feasibility to formulate a personalized exercise plan.(2)This study recommends that when applying HIIT,a low-volume protocol(for example,5 groups each time,1 minute each),3 times/week,and ride at 80%-95%of the maximum heart rate is used to achieve the theoretical best improvement effect.(3)Although MICT improves the quality of life,there is insufficient evidence that increasing exercise duration brings additional benefits.Therefore,this study recommends that when MICT is conducted,it should be carried out more than three times a week,with each training duration controlled between 25 and 60 minutes,and cycling at 50%-75%of the maximum heart rate,in order to achieve the theoretically expected best improvement effect.

ObjectiveTo investigate the efficacy of Xingpi capsules （XPC） in treating diarrhea-predominant irritable bowel syndrome （IBS-D） with spleen deficiency and elucidate its potential molecular mechanisms. MethodsA rat model of IBS-D with spleen deficiency was established by administering senna leaf in combination with restrained stress and swimming fatigue for 14 d. Ten specific pathogen free （SPF）-grade healthy rats were used as the normal control group. After successful modeling， SPF-grade rats were randomly divided into a model group， a pinaverium bromide group （1.5 mg·kg^-1）， and low- and high-dose XPC groups （0.135 and 0.54 g·kg^-1）， with 10 rats in each group. Rats in the normal control group and the model group were given distilled water by gavage， while the remaining groups were administered corresponding drug solutions by gavage once a day for 14 consecutive days. The rat body weights and fecal condition were observed every day， and the Bristol score was recorded. Enzyme-linked immunosorbent assay （ELISA） was used to determine the levels of 5-hydroxytryptamine （5-HT） in serum and colon tissue. Transmission electron microscopy was used to observe the microvilli and tight junctions in the colon. The integrity of the colonic barrier， intestinal motility， and expression of related pathway proteins were evaluated by hematoxylin-eosin （HE） staining， immunohistochemistry， and Western blot. ResultsCompared with those in the normal control group， rats in the model group showed a significantly decreased body weight and increased diarrhea rate， diarrhea grade， and Bristol score （P<0.01）. HE staining revealed incomplete colonic mucosa in the model group， with evident congestion and edema observed. Electron microscopy results indicated decreased density and integrity of the colonic barrier， shedding and disappearance of microvilli， and significant widening of tight junctions. The expression levels of colonic tight junction proteins Occludin and Claudin-5 were downregulated （P<0.01）， and the levels of 5-HT in serum and colon tissue were elevated （P<0.01）. The small intestine propulsion rate significantly increased （P<0.01）， and the expression of contractile proteins Ras homolog family member A （RhoA） and Rho-associated coiled-coil containing protein kinase 2 （ROCK2） in colon and phosphorylation of myosin light chain （MLC₂₀） were upregulated （P<0.01）. Compared with the model group， the treatment groups showed alleviated diarrhea， diarrhea-associated symptoms， and pathological manifestations of colon tissue to varying degrees. Specifically， high-dose XPC exhibited effectively relieved diarrhea， promoted recovery of colonic mucosal structure， significantly reduced congestion and edema， upregulated expression of Occludin and Claudin-5 （P<0.01）， decreased levels of 5-HT in serum and colon tissue （P<0.05，P<0.01）， significantly slowed small intestine propulsion rate （P<0.01）， and significantly downregulated expression of contractile proteins RhoA and ROCK2 in colon and phosphorylation of MLC₂₀ （P<0.05，P<0.01）. ConclusionXPC effectively alleviates symptoms of spleen deficiency and diarrhea and regulates the secretion of brain-gut peptide. The characteristics of XPC are mainly manifested in alleviating IBS-D with spleen deficiency from the aspects of protecting intestinal mucosa and inhibiting smooth muscle contraction， and the mechanism is closely related to the regulation of the 5-HT-RhoA/ROCK2 pathway expression.

Alzheimer's disease(AD)is the most prevalent cognitive disorder among the elderly.Malnutrition is a frequent nutritional issue within this population and is linked to negative clinical outcomes across various diseases.Recent studies indicate a significant association between malnutrition and both the development and progression of AD, highlighting the critical role of nutritional support in preventing and delaying the advancement of the disease.We discussed the diagnosis of malnutrition in patients with AD, the interrelationship between AD and malnutrition, the mechanisms connecting malnutrition to AD, and the impact of nutritional support on the management of AD.

OBJECTIVE:Prolonged sedentary behavior can acutely reduce peripheral and central vascular function,thereby increasing the risk of cardiovascular disease.Interrupting sedentary behavior may be a potential practical strategy to prevent vascular dysfunction caused by prolonged sitting.However,current research findings on its acute effects are inconsistent,and specific application recommendations have not yet been established.This study aims to perform a Meta-analysis on the acute effects of interrupting sedentary behavior on peripheral and central vascular function in adults and to explore its regulatory factors.METHODS:Following PRISMA reporting guidelines,literature search was conducted in March 2024 using the keywords of"interrupting,""sedentary,"and"vascular function"in the Web of Science Core Collection,PubMed,and China National Knowledge Infrastructure(CNKI)databases.Acute randomized crossover trials addressing the acute effects of interrupting sedentary behavior on peripheral and central vascular function in adults were included.Risk of Bias 2 developed by Cochrane was used to assess bias risk,and the Grading of Recommendations Assessment,Development,and Evaluation(GRADE)system was used to evaluate the evidence level.The"meta"and"metaphor"packages in R(version 4.2.0)were used for main effect aggregation(Hedge's g acted as the effect size indicator),publication bias testing,subgroup analysis,and regression analysis.RESULTS:Twenty-two randomized crossover trials involving 364 subjects(aged 21 to 70 years)were included.Meta-analysis results showed that compared with prolonged sitting,interrupting sedentary behavior acutely improved peripheral vascular blood flow volume(Hedge's g=0.48,95%confidence interval:0.14-0.82,P<0.01,I2=63%,low evidence level),shear stress(Hedge's g=0.65,95%confidence interval:0.37-0.93],P<0.01,I2=54%,moderate evidence level),and flow-mediated dilation(Hedge's g=0.43,95%confidence interval:0.15-0.72,P<0.01,I2=61%,moderate evidence level).Disease had a significant moderating effect on the main effect aggregation for blood flow volume(P=0.01 between subgroups),while the mode(P=0.01 between subgroups)and frequency(P=0.02 between subgroups)of interruptions had significant moderating effects on shear stress.Improvements in peripheral vascular shear stress from interrupting sedentary behavior were affected by age(β=-0.02,95%confidence interval:-0.03-0.01,P=0.09)and body mass index(β=-0.10,95%confidence interval:-0.18 to-0.02,P<0.01).Improvements in flow-mediated dilation were influenced by the total number of interruptions(β=-0.09,95%confidence interval:-0.17 to-0.01,P=0.03)and the duration of sitting during the control period(β=-0.21,95%confidence interval:-0.34 to-0.09,P<0.01).Each additional hour of sitting was associated with a 0.67%reduction in the acute improvement effect of flow-mediated dilation from interrupting sedentary behavior(P<0.01),and acute benefits disappeared when sitting control time exceeded 6 hours.A qualitative systematic review found that interrupting sedentary behavior did not significantly affect pulse wave velocity in various populations but could effectively prevent central vascular function decline in older adults due to prolonged sitting.CONCLUSION:Interrupting sedentary behavior acutely improves peripheral vascular blood flow volume(low evidence level),shear stress(moderate evidence level),and flow-mediated dilation(moderate evidence level)in adults and may prevent or protect against central vascular function decline in older adults due to prolonged sitting(very low evidence level).Characteristics of subjects(disease factors,sex,age,and body mass index),interruption intervention schemes(mode,frequency,total number of interruptions),and duration of sitting control all influence the acute improvement effects of interrupting sedentary behavior on vascular function.It is recommended that adults interrupt sedentary behavior with exercises involving large muscle groups,such as stair climbing,at high frequencies(e.g.,once every 40 minutes)with at least 5 minutes of moderate-to low-intensity activity each time,and limit the cumulative duration of prolonged sitting to no more than 6 hours per day.