Objective Recent studies have shown that high resting end tidal CO2 (PECO2)
is a marker for blood pressure sensitivity to high sodium intake by normot
ensive humans. The present study investigated the association of resting PE
CO2 with resting blood pressure in participants in the Baltimore Longitudin
al Study on Aging (BLSA).
Design PECO2 of 314 healthy participants (153 men and 161 women, aged 21 -7
9 years) was measured by a respiratory gas monitor during 25 min of seated
rest, and blood pressure every 5 min by an automated oscillometric system.
The independent associations of PECO2 and other variables with systolic (SB
P) and diastolic (DBP) blood pressure were analysed via multiple regression
. Sex differences in age-associated changes in PECO2 and in the role of pul
monary capacity in the PECO2 - blood pressure relationships were also studi
ed.
Results Resting PECO2 was an independent predictor of SEP in women (beta =
0.215; P < 0.0015; overall r(2) = 0.27; P < 0.0001), and accounted for more
than 10% of the variance in SEP in women over age 50 years. No such associ
ations of PECO2 with SEP of men, or with DBP of men or women, were observed
, PECO2 was lower in younger women (36.0 +/- 0.9 mmHg) than in younger men
(40.4 +/- 2.0), but higher in older women (37.1 +/- 0.5) than in older men
(35.5 +/- 0.4).
Conclusions PECO2 is an independent determinant of resting SEP in women, es
pecially those aged 50 years or more. The origin of individual differences
in resting PECO2 and its possible role in the development of chronic hypert
ension remain to be clarified. J Hypertens 1999, 17:1073-1080 (C) Lippincot
t Williams & Wilkins.