Neural Respiratory Drive And Pulmonary Ventilation During Tai Chi Exercise

Background:Chronic Pulmonary Disease (COPD) is one of the major causes ofmortality and morbidity throughout the world， pulmonaryrehabilitation which is an effective treatment for patients with COPDwas recommended by Global Initiative for Chronic Obstructive LungDisease （GOLD） except conventional treatment include inhaledcorticosteroid and bronchodilators. American ThoracicSociety/European Respiratory Society statement on pulmonaryrehabilitation noted that exercise training was wildly regarded asthe main modality of pulmonary rehabilitation, and pulmonaryrehabilitation exercise often used a treadmill or stationary cycleergo meter which were the traditional pulmonary rehabilitationmodality, but traditional pulmonary rehabilitation entailed theprovision of a treadmill or stationary cycle ergo meter whichapplication were limited for economic burden especially indeveloping countries where there were lots of COPD patients;Secondarily, location、travel and transport were barriers to uptakeand boring exercise modality was the barrier to complete pulmonaryrehabilitation thus the compliance was reduced, so as above mentionedbarriers to uptake and complete a treadmill or stationary cycle ergometer training which application were limited as pulmonaryrehabilitation treatment for COPD patients.Tai chi was derived from the17thcentury in China, it wascharacterized by a series of slow and quick continuous movements, integrated upper and lower limbs training, focused on breathingtechniques and meditation, flowing circular movements, slow and lightmindedness, it was not boring and was not easy to cause overworked,additionally, it was not limited by location so the compliance wouldbe higher than traditional pulmonary rehabilitation. But as aneffective pulmonary rehabilitation treatment, it is not known thatis the function of tai chi in COPD patients just because psychologicalcomfort, exercise on improving of heart function or it does play therole in respiratory physiology. So change of respiratory physiologywas investigated during tai chi exercise in COPD patients.Diaphragm was a major inspiratory pump muscle, and diaphragmelectromyogram (EMG) was the direct sign of diaphragm contraction，compared with traditional respiratory dynamic indicators, EMG was notinfluenced by the change of lung volume and gas constitution，andEMG recorded from a multipair esophageal electrode was an alternativeand reliable technique to asses neural respiratory drive, Tidalvolume （VT）、 minute ventilation (VE), respiratory frequency(RF),Oxygen uptake (VO2) and carbon dioxide production (VCO2) wereindicators to assess pulmonary ventilation function, Inspiratorycapacity (IC) before and after exercise was used to assess dynamichyperinflation, Twitch tension (TwQ) was used to assess quadricepsmuscle strength before and after exercise, indicators as abovementioned were mainly investigated content in this study.Observe neural respiratory drive, pulmonary ventilationindicators and the change of IC and TwQ before and after exercise inCOPD patients during tai chi exercise which is freedom exercisemodality, to investigate whether the neural respiratory drive can betested during tai chi exercise and the function of tai chi exercisein respiratory physiology of pulmonary rehabilitation. Subjects:Data from11stable patients with GOLD Ⅰto Ⅳ COPD (mean±SD FEV1%pred.61±27%)(age：61.6±7.7ys)（10men，1woman）wasanalyzed, all subjects were tested in our dynamic laboratory.Exclusion criteria were other respiratory diseases, significantobesity (BMI>30kg/m2), joint disease which precludes Tai Chi,allergy to latex, dysphagia, any contraindication to the passage ofan esophageal electrode for the measurement of diaphragm EMG,exacerbation in the4weeks prior to the study (defined as clinicalworsening requiring use of oral corticosteroids, antibiotics oradmission to hospital)，coronary heart disease. All patients hadpracticed Yang style tai chi for more than one year and at least onetreadmill exercise experience. Regular medicine such ascorticosteroid and bronchodilators was taken usually.Methods:Prior to each exercise, Magstim2002stimulator stimulated femoralnerve to assess quadriceps muscle strength by TwQ. The subject layon a specially designed chair from which was laid flat. The ankle ofthe right leg was placed in an inextensible strap that was positioned1-2cm above the lateral malleolus and connected to a strain guagewhich was calibrated before each test with know weight. Femoral nervestimulation was performed using a figure-of-eight coil powed byMagstim2002stimulator. The coil head was positioned high in thefemoral triangle just lateral to the femoral artery, and the best spotwhich resulted in the largest TwQ was marked by a marker-pen in orderto stimulate the same position throughout the range of the stimulator outputs from60%to100%. Then a multifunctional esophageal catheterfor recording of diaphragm EMG and esophageal pressure (Pes) waspassed through the nose. The depth of catheter was judged by thediaphragm EMG. IC was measured by a flow-spirometry before exercise.Diaphragm EMG and Pes were measured meanwhile VO2、VCO2、VT、RF andVEindicators of pulmonary ventilation function measured by the COSMEDportal exercise cardiorespiratory ‘cart’.After exercise IC was measured and after20min and60min TwQ wasmeasured, respectively.Results:The average diaphragm of root mean square EMG (RMS EMGdi)was74±35%during tai chi exercise, although compared with traditionalpulmonary rehabilitation，60%maximal load treadmill exercise，whichRMS EMGdiwas75±31%，both neural respiratory drive was similar， nosignificant differences (P>0.05),there was different change trendduring exercise，it was overall remarkably constant during tai chiexercise, which was in contrast to gradually decrease over thetreadmill after the initial increase； Yang style tai chi wasconsisted of10repeated session, RMS EMGdi also was periodic changedwith the unit of every session of tai chi exercise and RMS EMGdichanged in wave-shape increase with24different continuous movement，but it did not exist during treadmill exercise, but the interestingthing was that change tendency of every session was contrary to entireexercise, tai chi exercise gradually increase while treadmill wasrelatively constant. During the first session of tai chi exerciseRMS EMGdi was68±12%which was lower than81±7%during treadmillexercise, significant differences (P<0.05); During the middlesession, RMS EMGdi of tai chi exercise was similar with treadmill(70 ±5%vs74±5%), no significant differences (P>0.05); During the lastsession, RMS EMGdi was82±9%which was higher than66±1%duringtreadmill exercise, significant differences (P<0.05).The average Pes of tai chi exercise was similar with treadmill(22.5±7.0cmH2O vs23.1±7.8cmH2O), no significant differences(P>0.05), there was similar change trend of Pes with RMS EMGdi duringexercise，it was overall remarkably constant during tai chi exercise,which was in contrast to gradually decrease over the treadmill afterthe initial increase; Pes also was periodic changed with the unit ofevery session of tai chi exercise and it changed in wave-shapeincrease with24different continuous movement， but it did not existduring treadmill exercise; Change tendency of every session wascontrary to entire exercise, tai chi exercise gradually increasewhile treadmill was relatively constant. During the first session oftai chi exercise Pes was23.6±1.9cmH2O which was lower than26.6±1.9cmH2O during treadmill exercise, significant differences(P<0.05); During the middle session of tai chi exercise Pes was21.6±0.2cmH2O which was lower than24.1±0.2cmH2O during treadmillexercise, significant differences (P<0.05); During the last session,Pes of tai chi exercise was similar with treadmill(22.3±0.8cmH2Ovs22.4±0.3cmH2O), no significant differences (P>0.05).Change trend of VO2、VT、RF and VEwhich were indicators of pulmonaryventilation were similar with RMS EMGdi during tai chi exercise, alsowas periodic changed in wave-shape increase with24differentcontinuous movement in the unit of every session of tai chi exercise;RF was different from other indicators of pulmonary ventilationduring treadmill exercise，it was overall relatively constant，theaverage RF during tai chi exercise was lower than treadmill exercise(24.3±2.0b/m vs28.4±4.9b/m) significant differences（P<0.05）; The average VTof tai chi exercise was similar with treadmill (1.1±0.2L vs1.1±0.3L), no significant differences (P>0.05); Theaverage VEof tai chi exercise was similar with treadmill (27.9±6.0L/m vs34.0±12.1L/m), no significant differences (P>0.05); Theaverage VO2during tai chi exercise was lower than treadmill exercise(0.74±0.23L/m vs0.88±0.32L/m),significant differences（P<0.05）.During the first session of exercise, change trend of VO2、VTandVEgradually increase during tai chi exercise while treadmill wasrelatively constant; VTduring tai chi exercise was similar withtreadmill (1.1±0.2L vs1.1±0.3L), no significant differences(P>0.05); VE during tai chi exercise was lower than treadmill exercise(27.2±3.6L/m vs32.2±6.6L/m),significant differences（P<0.05）;VO2during tai chi exercise was lower than treadmill exercise (0.80±0.17L/m vs0.91±0.21L/m),significant differences（P<0.05）; RFwas different from above indicators of pulmonary ventilation duringtai chi and treadmill exercise，it was overall relatively constant，the average RF during tai chi exercise was lower than treadmillexercise (23.7±0.9b/m vs27.3±1.3b/m) significant differences（P<0.05）;During the middle session of exercise, change trend of VO2、VTandVEgradually increase during tai chi exercise; VTduring tai chiexercise was similar with treadmill (1.2±0.04L vs1.2±0.01L), nosignificant differences (P>0.05); VEduring tai chi exercise was lowerthan treadmill exercise (29.5±2.2L/m vs35.1±0.4L/m),significantdifferences（P<0.05）;VO2during tai chi exercise was lower thantreadmill exercise (0.77±0.09L/m vs0.93±0.01L/m),significantdifferences（P<0.05）; RF was different from above indicators ofpulmonary ventilation during tai chi and treadmill exercise，it wasoverall relatively constant，the average RF during tai chi exercise was lower than treadmill exercise (25.8±0.7b/m vs28.8±0.2b/m)significant differences（P<0.05）.During the last session of exercise, change trend of VO2、VTandVEgradually increase during tai chi exercise; VTduring tai chiexercise was higher than treadmill (1.2±0.04L vs1.1±0.04L),significant differences (P<0.05); VEduring tai chi exercise wassimilar with treadmill exercise (30.2±2.0L/m vs31.6±1.2L/m), nosignificant differences（P>0.05）;VO2during tai chi exercise wassimilar with treadmill exercise (0.80±0.09L/m vs0.81±0.04L/m),nosignificant differences（P>0.05）; The average RF during tai chiexercise was lower than treadmill exercise (25.9±1.0b/m vs28.5±0.3b/m) significant differences（P<0.05）.As expected both tai chi and treadmill exercise elicited a fallin IC from2.20±0.71L to2.01±0.79L for tai chi and2.26±0.68Lto1.92±0.67L in the case of treadmill exercise, but there was notstatistically significant after tai chi exercise（P>0.05）while therewas after treadmill （P<0.05）.After exercise, quadriceps muscle strength was decreased aftertai chi exercise while increased after treadmill exercise, at20minutes it was decreased from8.7±1.8kg to7.6±2.0kg after tai chiexercise while increased from8.1±1.8kg to8.5±2.1kg, significantdifferences（P<0.05）; at60minutes it was decreased to7.8±2.9kgafter tai chi exercise while increased to8.2±2.0kg, significantdifferences（P<0.05）。After exercise，leg fatigue and dynpnea of borg scale was samebetween tai chi and treadmill exercise, but2subjects did not finishtai chi exercise while there were3in treadmill exercise，and in thesesubjects2of them did not finish both tai chi and treadmill exercise，1of them only did not finish treadmill exercise, subjects played longer exercise time in tai chi exercise.Conclusions:Neural respiratory drive can be tested during tai chi exercisewhich is freedom exercise modality, and compared with the traditionalpulmonary rehabilitation modality treadmill, there was differentchange trend during exercise.Both neural respiratory drive was similar， no significantdifferences (P>0.05), but during the last session, RMS EMGdi was higerthan treadmill exercise, significant differences (P<0.05).Pes of tai chi exercise was similar with treadmill, no significantdifferences (P>0.05).VTof tai chi exercise was similar with treadmill, no significantdifferences (P>0.05); VEof tai chi exercise was similar withtreadmill, no significant differences (P>0.05); but the average RFduring tai chi exercise was lower than treadmillexercise,significant differences（P<0.05）and VTduring tai chiexercise was higher than treadmill during the last session,significant differences (P<0.05)Tai chi exercise elicited a fall in IC, but there was notstatistically significant （P>0.05）and after exercise,quadricepsmuscle strength was decreased.Tai chi exercise was played longer than treadmill exercise.