***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Chronic work-related stress is an independent risk factor for cardiometabolic diseases and associated mortality , particularly when compounded by a sedentary work environment . The purpose of this study was to determine if an office worksite-based hatha yoga program could improve physiological stress , evaluated via heart rate variability ( HRV ) , and associated health-related outcomes in a cohort of office workers . Methods Thirty-seven adults employed in university-based office positions were r and omized upon the completion of baseline testing to an experimental or control group . The experimental group completed a 10-week yoga program prescribed three sessions per week during lunch hour ( 50 min per session ) . An experienced instructor led the sessions , which emphasized asanas ( postures ) and vinyasa ( exercises ) . The primary outcome was the high frequency ( HF ) power component of HRV . Secondary outcomes included additional HRV parameters , musculoskeletal fitness ( i.e. push-up , side-bridge , and sit & reach tests ) and psychological indices ( i.e. state and trait anxiety , quality of life and job satisfaction ) . Results All measures of HRV failed to change in the experimental group versus the control group , except that the experimental group significantly increased LF : HF ( p = 0.04 ) and reduced pNN50 ( p = 0.04 ) versus control , contrary to our hypotheses . Flexibility , evaluated via sit & reach test increased in the experimental group versus the control group ( p < 0.001 ) . No other adaptations were noted . Post hoc analysis comparing participants who completed ≥70 % of yoga sessions ( n = 11 ) to control ( n = 19 ) yielded the same findings , except that the high adherers also reduced state anxiety ( p = 0.02 ) and RMSSD ( p = 0.05 ) , and tended to improve the push-up test ( p = 0.07 ) versus control . Conclusions A 10-week hatha yoga intervention delivered at the office worksite during lunch hour did not improve HF power or other HRV parameters . However , improvements in flexibility , state anxiety and musculoskeletal fitness were noted with high adherence . Future investigations should incorporate strategies to promote adherence , involve more frequent and longer duration s of yoga training , and enrol cohorts who suffer from higher levels of work-related stress . Trial registration CONTEXT Tai Chi exercise has been shown to improve cancer-related fatigue ( CRF ) and autonomic nervous system ( ANS ) balance in some cancer patients or survivors ; however , such effects are yet to be verified in nasopharyngeal carcinoma ( NPC ) patients undergoing chemoradiotherapy . OBJECTIVES To explore the effects of Tai Chi exercise on CRF in NPC patients undergoing chemoradiotherapy and then to evaluate ANS information indicated by heart rate variability parameters and their association with CRF . METHODS A r and omized controlled trial of Tai Chi exercise was conducted from January 2014 to August 2015 . Participants in the Tai Chi group practice d Tai Chi a one-hour session , five sessions/week during chemoradiotherapy . Participants in the control group received usual care . The primary end points were scores of the multidimensional fatigue symptom inventory-short form ( MFSI-SF ) . Secondary end points were heart rate variability parameters , including normalized low-frequency ( nLF ) power , normalized high-frequency ( nHF ) power , and the nLF/nHF ratio , and their association with CRF . RESULTS One hundred fourteen patients were recruited in this study , and 83 patients completed the trial . The Tai Chi group and the control group had comparable baseline characteristics . After chemoradiotherapy , the Tai Chi group exhibited lower MFSI-SF total score and three negative subscale ( general , physical , and emotional fatigue ) scores and higher vigor score compared with the control group ( P < 0.01 for all ) . The nLF/nHF ratio was significantly lower in the Tai Chi group compared to the control group after chemoradiotherapy . The MFSI-SF total score was markedly correlated with the nLF/nHF ratio . CONCLUSION Tai Chi exercise is conducive to alleviate  CRF  in NPC patients undergoing chemoradiotherapy . The improvement in ANS balance might fit into the process of Tai Chi for CRF management in this population The present study examined the effects of a 12-week Tai Chi ( TC ) training regimen on heart rate variability ( HRV ) , symptomatology , muscle fitness and body composition in women with fibromyalgia . Participants were r and omly assigned to either a  TC training group ( n = 18 ) or a  control group ( n = 19 ) .  HRV , symptomatology , muscle fitness and body composition were measured before and after 12 weeks . There were significant decreases ( p < 0.05 ) in sympathovagal balance ( LnLF/LnHF ) , sympathetic tone ( LnLF , nLF ) , pain , and fatigue , and significant increases ( p < 0.05 ) in parasympathetic tone ( LnHF , nHF ) , strength and flexibility following TC compared with no changes after control . The changes in LnLF and LnLF/LnHF were correlated with changes in pain . There were no significant changes in HR , sleep quality and body composition after TC or control . TC may be an effective therapeutic intervention for improving sympathovagal balance , pain , fatigue , strength and flexibility in women with fibromyalgia Objective : Behavioral therapies are first-line for preschoolers with attention-deficit hyperactivity disorder ( ADHD ) . Studies support yoga for school-aged children with ADHD ; this study evaluated yoga in preschoolers on parent- and teacher-rated attention/challenging behaviors , attentional control ( Kinder Test of Attentional Performance [ KiTAP ] ) , and heart rate variability ( HRV ) . Methods : This r and omized waitlist-controlled trial tested a 6-week yoga intervention in preschoolers with ≥4 ADHD symptoms on the ADHD Rating Scale-IV Preschool Version . Group 1 ( n = 12 )  practice d yoga first ;  Group 2 ( n = 11 )  practice d yoga second . We collected data at 4 time points : baseline , T1 ( 6 weeks ) , T2 ( 12 weeks ) , and follow-up ( 3 months after T2 ) . Results : At baseline , there were no significant differences between groups . At T1 , Group 1 had faster reaction times on the KiTAP go/no-go task ( p = 0.01 , 95 % confidence interval [ CI ] , −371.1 to −59.1 , d = −1.7 ) , fewer distractibility errors of omission ( p = 0.009 , 95 % CI , −14.2 to −2.3 , d = −1.5 ) , and more commission errors ( p = 0.02 , 95 % CI , 1.4–14.8 , d = 1.3 ) than Group 2 . Children in Group 1 with more severe symptoms at baseline showed improvement at T1 versus control on parent-rated Strengths and Difficulties Question naire hyperactivity-inattention ( & bgr ; = −2.1 , p = 0.04 , 95 % CI , −4.0 to −0.1 ) and inattention on the ADHD Rating Scale ( & bgr ; = −4.4 , p = 0.02 , 95 % CI , −7.9 to −0.9 ) . HRV measures did not differ between groups . Conclusion : Yoga was associated with modest improvements on an objective measure of attention ( KiTAP ) and selective improvements on parent ratings Highly stressed employees are subject to greater health risks , increased cost , and productivity losses than those with normal stress levels . To address this issue in an evidence -based manner , worksite stress management programs must be able to engage individuals as well as capture data on stress , health indices , work productivity , and health care costs . In this r and omized controlled pilot , our primary objective was to evaluate the viability and proof of concept for two mind-body workplace stress reduction programs ( one therapeutic yoga-based and the other mindfulness-based ) , in order to set the stage for larger cost-effectiveness trials . A second objective was to evaluate 2 delivery venues of the mindfulness-based intervention ( online vs. in-person ) . Intention-to-treat principles and 2 ( pre and post ) × 3 ( group ) repeated- measures analysis of covariance procedures examined group differences over time on perceived stress and secondary measures to clarify which variables to include in future studies : sleep quality , mood , pain levels , work productivity , mindfulness , blood pressure , breathing rate , and heart rate variability ( a measure of autonomic balance ) . Two hundred and thirty-nine employee volunteers were r and omized into a therapeutic yoga worksite stress reduction program , 1 of 2 mindfulness-based programs , or a control group that participated only in assessment . Compared with the control group , the mind-body interventions showed significantly greater improvements on perceived stress , sleep quality , and the heart rhythm coherence ratio of heart rate variability . The two delivery venues for the mindfulness program produced basically equivalent results . Both the mindfulness-based and therapeutic yoga programs may provide viable and effective interventions to target high stress levels , sleep quality , and autonomic balance in employees Objectives Since ageing is associated with a decline in pulmonary function , heart rate variability and spontaneous baroreflex , and recent studies suggest that yoga respiratory exercises may improve respiratory and cardiovascular function , we hypothesised that yoga respiratory training may improve respiratory function and cardiac autonomic modulation in healthy elderly subjects . Design 76 healthy elderly subjects were enrolled in a r and omised control trial in Brazil and 29 completed the study ( age 68±6 years , 34 % males , body mass index 25±3 kg/m2 ) . Subjects were r and omised into a 4-month training program ( 2 classes/week plus home exercises ) of either stretching ( control , n=14 ) or respiratory exercises ( yoga , n=15 ) . Yoga respiratory exercises ( Bhastrika ) consisted of rapid forced expirations followed by inspiration through the right nostril , inspiratory apnoea with generation of intrathoracic negative pressure , and expiration through the left nostril . Pulmonary function , maximum expiratory and inspiratory pressures ( PEmax and PImax , respectively ) , heart rate variability and blood pressure variability for spontaneous baroreflex determination were determined at baseline and after 4 months . Results Subjects in both groups had similar demographic parameters . Physiological variables did not change after 4 months in the control group . However , in the yoga group , there were significant increases in PEmax ( 34 % , p<0.0001 ) and PImax ( 26 % , p<0.0001 ) and a significant decrease in the low frequency component ( a marker of cardiac sympathetic modulation ) and low frequency/high frequency ratio ( marker of sympathovagal balance ) of heart rate variability ( 40 % , p<0.001 ) . Spontaneous baroreflex did not change , and quality of life only marginally increased in the yoga group . Conclusion Respiratory yoga training may be beneficial for the elderly healthy population by improving respiratory function and sympathovagal balance . Trial Registration CinicalTrials.gov identifier : NCT00969345 ; trial registry name : Effects of respiratory yoga training ( Bhastrika ) on heart rate variability and baroreflex , and quality of life of healthy elderly subjects PURPOSE to compare the effects of a short style of Tai Chi versus brisk walking training programme on aerobic capacity , heart rate variability ( HRV ) , strength , flexibility , balance , psychological status and quality of life in elderly women . METHODS nineteen community-dwelling , sedentary women ( aged 71.4 + /- 4.5 years ) were r and omly assigned to Tai Chi Chuan ( TCC ; n = 11 ) or brisk walking group ( BWG ; n = 8) . A separate group of elderly women was recruited from the same population to act as a sedentary comparison group ( SCG ; n = 8) . The exercise groups met for 1 h , three days per week for 12 weeks . Outcomes measured before and after training included estimated VO2max , spectral analysis of HRV ( high-frequency , low-frequency power as well as high- and low-frequency power in normalised units ) as a measure of autonomic control of the heart , isometric knee extension and h and grip muscle strength , single-leg stance time , the State Trait Anxiety Inventory ( STAI ) , Profile of Mood States ( POMS ) and Short Form-36 ( SF-36 ) question naires . RESULTS significant improvement was seen in estimated VO(2)max in the TCC group ( TCC versus SCG P = 0.003 , TCC versus BWG P = 0.08 ) . The mean within-person change of high-frequency power in normalised units ( HFnu ) increased [ 8.2 ( 0.14 - 16.3 ) ] , representing increased parasympathetic activity , and low-frequency power in normalised units ( LFnu ) decreased [ -8.7 ( -16.8 - 0.5 ) ] , representing decreased sympathetic activity , in the TCC group only . Significant gains were also seen in the non-dominant knee extensor strength and single-leg stance time ( TCC versus BWG P < 0.05 ) . CONCLUSIONS a short style of TCC was found to be an effective way to improve many fitness measures in elderly women over a 3-month period . TCC was also found to be significantly better than brisk walking in enhancing certain measures of fitness including lower extremity strength , balance and flexibility BACKGROUND The stimulation-seeking theory posits that individuals with low habitual autonomic arousal levels will seek stimulation to increase their arousal to more optimal levels . Because of their assumed high optimal stimulation levels , persons characterized by 
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CONCLUSIONS Stress reduction may be attributed to sympathetic-vagal balance modulated by mind⁻body exercises .
Tai Chi/Yoga could be an alternative method for stress reduction for people who live under high stress or negative emotions