Pulmonary vascular resistances during exercise in normal subjects: a systematic review

The physiological range of pulmonary vascular resistance (PVR) and total pulmonary resistance (TPR), and the impact of exercise, age and posture have been a matter of debate for many years. We performed a systematic literature review including all right heart catheterisation data where individual PVR and TPR of healthy subjects both at rest and exercise were available. Data were stratified according to age, exercise level and posture. Supine resting PVR in subjects aged <24 yrs, 24-50 yrs, 51-69 yrs and >= 70 yrs was 61 +/- 23, 69 +/- 28, 86 +/- 15 and 90 +/- 39 dyn.s.cm(-5), respectively. Corresponding TPR was 165 +/- 50, 164 +/- 46, 226 +/- 64 and 223 +/- 45 dyn.s.cm(-5), respectively. During moderate exercise in subjects aged <= 50 yrs, an 85% increase in cardiac output was associated with a 25% decrease in TPR (p<0.0001) and a 12% decrease in PVR (p<0.01). At 51-69 yrs of age there was no significant decrease in TPR and PVR. In individuals aged >= 70 yrs TPR even increased by 17% (p=0.01), while PVR did not change significantly. At higher exercise levels, TPR decreased in all age groups. In the upright position, based on a limited number of data, resting TPR and PVR were higher than in the supine position and decreased more prominently during exercise, suggesting the release of resting pulmonary vasoconstriction. These data may form a basis to define normal PVR at rest and exercise.