Six-minute Walk Test Performance In Home-dwellingmiddle-aged And Older Individuals And Chronic Stroke Patients As Well As Its Relations With Grip Strength And VO₂

1 ObjectivesThe present study had two main objectives:firstly,we aimed at measuring the six-minute walk test?6MWT?performance in independent home-dwelling middle-aged and older Chinese individuals so that we can compare their levels with the results of people from various countries in the current literature.Meanwhile,the correlation between 6MWT distance and the volume of oxygen intake?VO₂?tested from cardiopulmonary test,and the correlation between 6MWT distance and muscle strength were analyzed.Secondly,we aimed at determining 6MWT performance in stroke patients at chronic rehabilitation stage,and to understand its relations with VO₂ and muscle strength.Through the study,we wish to learn their physical fitness level,make clear their difference with common dwellers,and understand better about these parameters to provide guide and reference for exercise rehabilitation in stroke patients.2 MethodsThis project is an observation study which includes two parts.In the first part of the study,a total of 106 middle-aged and older Chinese individuals were recruited in the communities around Suzhou University.All subjects accepted 6MWT with heart rate,blood pressure and rate of perceived exertion?RPE?recorded before and after test.Meanwhile,handgrip strength test?n=106?and graded exercise tests for VO₂?n=46?were performed.In the second part,26 chronic stroke patients were recruited and accepted the 6MWT,VO₂ and handgrip strength tests.All data were analyzed using SPSS 23.0statistic software.3 ResultsIn the first part,we found that the 6MWT distance was 543.3±67.2 m with a total work of 351.0±62.8 kJ in the middle-aged and older Chinese individuals.The measured6MWT distance accounted for⁸3-121%of the predicted distance calculated out from6MWT distance equations published in related studies.The distances ambulated at each minute were similar among the 6 minutes.6MWT distance was significantly associated with age and sex:it was larger in younger than in elder and larger in male than in female.Heart rate,systolic and diastolic blood pressure,and RPE scale significantly increased at post-6MWT.VO₂ at R=1 was 1238.3±342.3 ml/min?18.6±4.7 ml/min/kg?,and handgrip strength was 29.8±9.6 kg.The 6MWT distance was significantly correlated with both VO₂?r=0.549,p<0.001,n=46?and handgrip strength?r=0.359,p<0.001,n=106?in a positive linear way.In the second part,we found that the 6MWT distance of stroke patients was 428.7±145.0 m with a total work of 288.6±117.6 kJ.The measured 6MWT distance accounted for⁶2-92%of the predicted distance calculated out from 6MWT distance equations published in related studies.The measured distance was significantly smaller than the one in non-stroke community dwellers of similar age,height and weight.VO₂?at R=1?was1094.8±278.8 ml/min?15.9±2.3 ml/min/kg?.The handgrip strength of the affected side was 28.0±11.5 kg,and of the unaffected side was 34.2±10.2 kg.There was no correlations found either between 6MWT distance and VO₂,or between 6MWT distance and handgrip strength.4 ConclusionsThe 6MWT distance covered by independent home-dwelling middle-aged and older individuals was⁵43 m,which is reasonable within the middle range of the predicted distance according to previous studies.6MWT was strongly correlated with VO₂ and handgrip strength,suggesting that 6MWT performance is associated with both aerobic capacity and muscle fitness.The 6MWT distance ambulated by the stroke patients was⁴28 m,suggesting the decreased walking ability,and it has no correlation with either cardiopulmonary function or peripheral muscle strength,suggesting that stroke patients'walking ability is most likely affected by some other important factors than cardiopulmonary function or peripheral muscle strength,thereby it is inappropriate to use6MWT as a replacement of cardiorespiratory function exercise test to evaluate endurance fitness in chronic stroke patients.