Symptoms of low blood pressure: a population study.

OBJECTIVE: To establish whether an association exists between blood pressures in the "low normal" range and common symptoms such as tiredness, dizziness, headache, and palpitation, as suggested by French and German medical practice but not English or American medical practice. DESIGN: Cross sectional population based survey (the health and lifestyle survey) of blood pressure measurements and self reported common symptoms. Results were analysed by combined stratification and logistic regression. SUBJECTS: 7383 (82%) Adults aged 18 and over chosen from the electoral register in England, Wales, and Scotland for the health and lifestyle survey, in whom satisfactory physiological measurements were taken, from 9003 in the interviewed sample. MAIN OUTCOME MEASURES: Body mass index, smoking, social class, exercise, self declared physical illnesses, hours slept, use of drugs, and psychological illness as determined with the general health questionnaire assessed as potential confounders. RESULTS: True confounders were sex, age, taking of drugs, physical illness, exercise, and body mass index. A negative association was found between systolic blood pressure and self reported tiredness and feeling faint, which persisted after adjustment for the confounders. The association was strongest in women aged under 50. A negative association between systolic blood pressure and headache and a positive association between systolic blood pressure and palpitation were explained by confounding by age. CONCLUSIONS: Systemic hypotension is associated with persistent tiredness but treatment is not suggested as either possible or necessary. Instead, low blood pressures may be associated with opposite effects on mortality contrasted with morbidity.