BACKGROUND : Norm-referenced equations to predict the 6-minute walk distance (6MWD) in healthy Japanese subjects have not been established. The current study aimed to determine the reference values for 6MWD in healthy Japanese adults.
METHODS : Ninety-seven healthy Japanese men and women aged 40-79 years were recruited from Kyoto city using posters and flyers. Measurements of 6MWD were performed twice on an indoor 30 m track with 20 minutes rest between the two tests. Before performing the tests, age, gender, height, body weight, waist circumference, a questionnaire for health status, spirometry, and a 12-lead electrocardiogram were recorded. The 6MWD was measured following guidelines published in 2002 by the American Thoracic Society.
RESULTS : The mean age of the study subjects was 57.0±9.4, and 63 of the 97 subjects were female. The mean 6MWD for all subjects was 672±83 m, with a range of 483-903 m. The 6MWD is significantly correlated with age, height, waist circumference, forced vital capacity (FVC), and forced expiratory volume in one second (FEV₁). A multiple linear model showed age, waist circumference, and FVC were significantly associated with 6MWD and the model explained 35% of the variability in 6MWD. When FVC was replaced by height, the regression model also explained 32% of the variation. The measured 6MWD of Japanese subjects was similar to the predicted 6MWD using the equations derived from Caucasian subjects.
CONCLUSIONS : The 6MWD was affected to a substantial degree by age, waist circumference, height, and FVC in healthy Japanese adults.

We report two cases of older heart failure (HF) patients who improved pulmonary congestion and maintained functional capacity with tokishakuyakusan. Case 1 was an 83-year-old woman who previously treated with percutaneous coronary intervention for angina and had multiple comorbidities such as chronic kidney disease and rheumatoid arthritis. Despite of multiple medications including 3 kinds of diuretics, general fatigue that interferes with her daily life, marked pulmonary congestion, and leg edema remained. After prescription of tokishakuyakusan, urine volume increased rapidly and HF symptoms were alleviated so that 2 diuretics were successfully discontinued. Case 2 was an 88-year-old man with chronic atrial fibrillation and severe mitral regurgitation with worsening dyspnea on effort, paroxysmal nocturnal dyspnea, and leg edema. Tokishakuyakusan was effective for improving these HF symptoms and he returned to normal life without additional HF treatment. For elderly HF patients, tokishakuyakusan is considered to be effective to improve blood deficiency/stasis pattern and fluid retention, which enables these patients to make their daily life without being disturbed by severe HF symptoms.