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Table 1 Descriptive Statistics of the Study Population (N = 1,056)

From: Interobserver variability of ventilatory anaerobic threshold in asymptomatic volunteers

Parameter Missing data, n n (%) Median (interquartile range)
Men   515 (48.8%)  
Age, years    60 (49–69)
Weight, kg    79 (69–90)
Height, cm    169 (162–176)
BMI, kg/m2    27.3 (24.6–30.6)
 BMI ≥ 30 kg/m2   298 (28.2%)  
Smoking status 2   
 Never smokers   404 (38.3%)  
 Former smokers   485 (46.0%)  
 Current smokers   165 (15.7%)  
Physically activea   870 (82.4%)  
Myocardial infarction 2 25 (2.4%)  
Atrial fibrillation 8 54 (5.1%)  
Heart failure 125 30 (3.2%)  
Fractional shortening below normalb 324 2 (0.3%)  
Heart operation 1 22 (2.1%)  
Pacemaker 3 5 (0.5%)  
Previous pulmonary disease 2 52 (4.9%)  
Chronic bronchitisc 1 53 (5.0%)  
Asthma 4 55 (5.2%)  
Maximum exercise duration, s    536 (420–670)
Maximum power, W    148 (132–196)
peak VO2, mL/min 2   1,812 (1,482–2,292)
VO2@AT, mL/min    1,009 (867–1,204)
VO2@AT/peak VO2 reference, % d    54.6 (47.1–63.7)
VO2@AT/peak VO2 reference < 45% d   163 (15.4%)  
RER@AT    0.82 (0.77–0.86)
FEV1/FVC, % 3   75.7 (71.4–79.7)
FEV1/FVC < 70%   199 (18.9%)  
  1. Anamnestic data based on survey by professional interviewer. Continuous data are expressed as the median (25th; 75th quartile). Nominal data are given as percentages
  2. a Volunteers were asked about their physical activity and categorized as “Physically active” in case of 1–2 h of activity per week in summer and winter
  3. b The echocardiographic parameter “fractional shortening” was calculated as (left ventricular diastolic – systolic diameter [in cm]) × 100. Pathologic values were < 19% in males and < 21% in females
  4. c Subgroups may overlap
  5. d Predicted values were calculated according to Gläser S et al. [28] These were: peak VO2 in males = 254.76–22.69 × age [years] + 17.25 × height [cm] + 4.41 × weight [kg]; and peak VO2 in females = −54.74 – 9.81 × age [years] + 9.92 × height [cm] + 8.06 × weight [kg]
  6. BMI Body mass index, peak VO2 Peak oxygen uptake, VO2@AT Oxygen uptake at the aerobic-anaerobic threshold, RER Respiratory exchange ratio, FEV1/FVC Forced expiratory volume in 1 s/forced vital capacity