Resting end-tidal CO2 association with age, gender, and personality

Objectives: A previous study found that individuals with blood pressure sensitivity to high sodium intake tend to have a high resting partial pressure of end-tidal CO2 (PetCO(2)). The present study analyzed the test-retest reliability of individual PetCO(2) over 6 months, and the association of individual PetCO(2) with age, gender, and personality characteristics. Methods: PetCO(2) of 104 men and women (mean ages 42.1 +/- 1.5 years) was monitored via a respiratory gas monitor for 25 minutes during each of three sessions over an 11-day interval, and 59 subjects also participated in a 25-minute Follow-up session 261 +/- 10 days later. Each subject completed the NEO Personality Inventory. Results: PetCO(2) remained stable within and between monitoring sessions over a 6-month period. PetCO(2) was higher in men than in women, and decreased progressively over the life span. PetCO(2) was not correlated with the Extraversion, Openness, Agreeableness, or Conscientiousness Scales of the NEO Personality Inventory, but was highly positively associated with the Neuroticism Scale of the NEO Personality Inventory, and with its subscales. Conclusions: High resting end-tidal CO2 tends to be a stable individual characteristic that is accompanied by a tendency to worry and experience negative emotions.