Physiological cardio-respiratory variables in the HUNT 3 Fitness study stratified by intensity levels, sex and age groups.

<p>Data are presented as arithmetic mean ± SD. Workload: treadmill exercise load, fc: cardiac frequency, fB: breathing frequency, VE: minute ventilation, VT: tidal volume, VCO2: expired carbon dioxcide, VO2: oxygen uptake, R: respiratory exchange ratio, BMI: body mass index, VThan: ventilatory anaerobic threshold, RCP: respiratory compensation point.</p><p>Physiological cardio-respiratory variables in the HUNT 3 Fitness study stratified by intensity levels, sex and age groups.</p

Correlations between V_E and VCO₂ from test start up to V_Than: The HUNT 3 fitness study.

<p>Correlations between V_E and VCO₂ from test start up to V_Than: The HUNT 3 fitness study.</p

Correlations between EqVCO2VThan (ventilatory efficiency at ventilator anaerobic threshold) and age groups: The HUNT 3 fitness study.

<p>Correlations between EqVCO2VThan (ventilatory efficiency at ventilator anaerobic threshold) and age groups: The HUNT 3 fitness study.</p

Ventilatory equivalents at peak exercise and at ventilatory anaerobic threshold in the HUNT 3 fitness study.

<p>Data are presented as arithmetic mean ± SD. EqVO2 and EqVCO2: ventilatory efficiency.</p><p>Ventilatory equivalents at peak exercise and at ventilatory anaerobic threshold in the HUNT 3 fitness study.</p

Descriptive data for men and women in the HUNT 3 fitness study.

<p>Data are presented as arithmetic mean ± SD. BMI: bod mass index.</p><p>Descriptive data for men and women in the HUNT 3 fitness study.</p

Multiple linear regression models for predicting key cardio respiratory variables from non-exercise variables: The HUNT 3 fitness study.

<p>VEpeak: peak ventilation, VECO2: peak expiration of carbon dioxide, VThan: ventilatory anaerobic threshold, VTpeak: peak tidal volume, EqVCO2VThan and EqVO2VThan: ventilatory efficiency at ventilatory anaerobic threshold, R2: coefficient of variation, SEE: standard error of the estimate.</p><p>Multiple linear regression models for predicting key cardio respiratory variables from non-exercise variables: The HUNT 3 fitness study.</p

Peak respiratory variables in the HUNT 3 fitness study stratified by sex and height.

<p>Data are presented as arithmetic mean ± SD. VE: ventilation, VT: tidal volume, fB: breathing frequency.</p><p>Peak respiratory variables in the HUNT 3 fitness study stratified by sex and height.</p

Ventilatory efficiency and oxygen uptake presented in fitness quartiles: The HUNT 3 fitness study.

<p>Data are presented as arithmetic mean ± SD. VEVThan•VCO2VThan-1: ventilatory efficiency at ventilatory anaerobic threshold. Q1-4: quartiles of ventilatory efficiency and oxygen uptake.</p><p>Ventilatory efficiency and oxygen uptake presented in fitness quartiles: The HUNT 3 fitness study.</p

Correlation plots between measured and predicted VO_2peak with 95% prediction bands from peak treadmill performance (A and B), and submaximal treadmill performance (C and D).

<p>Correlation plots between measured and predicted VO_2peak with 95% prediction bands from peak treadmill performance (A and B), and submaximal treadmill performance (C and D).</p

Decline of oxygen uptake (VO₂) relative to age.

<p>Mean and SD for each age group is presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064319#pone-0064319-t002" target="_blank">Table 2</a>.</p