[Arterial pressure in obese subjects during ergometric stress test and recovery]

In obesity, the systemic resistances (SR) are reduced while the blood volume is increased. The rise of cardiac output (CO), stress-induced, produces an increase in blood pressure (BP), as an hypertensive behavior of the stress-response. The aim of our study is to evaluate if, in obese subjects, the considerable increase of BP is more related to the rise of CO than to the rise of SR. For this reason we studied the behavior of BP through indexes derived from the ratio of SBP values at the 1st, 3rd, 5th, 10th minutes of the recovery by the SBP value at the acme of stress. These indexes are under neurovegetative control, and were shown to be impaired in hypertensive pts. The results of ergometric stress test (EST) of 37 obese subjects (Ob+) (27 males and 10 females, mean age 46.2 +/- 7.3 years), determined according to Lorentz's formula, was compared with the parameters deduced from the EST of 18 normal subjects (Ob-) (13 males and 5 females, mean age 36.7 +/- 8.5). The exercise showed an increase, more pronounced in Ob+ subjects, of SBP and DBP, and this also persisted in the recovery phase. Although BP was significantly higher in the Ob+group, the SBP indexes did not differ in the two groups. Then, from these data it can be deduced that, although during EST in obese subjects there is an absolute increase of BP and this persists in the recovery phase, the behavior of this parameter probably cannot be related to alteration of neurovegetative system as demonstrated by the normal SBP indexes.