Pressor response to stress and exercise in the young: intracellular ion content relationships and prognostic implications.
The relationships between intracellular Na+ (Nai) and K+ (Ki) content, blood pressure and peripheral hemodynamics were investigated in young subjects with a family history of hypertension or with borderline hypertension. A direct correlation was found between Nai and pressor response to stress and exercise; after a short-term low-salt diet a parallel decrease was found in Nai and in pressor response to provocative tests. On the contrary, Ki was inversely related to diastolic blood pressure (DBP) both a rest and during mental and physical stimulation. The mechanism by which alterations in intracellular ion content lead to hemodynamic changes may be mediated by a reduced vasodilatory capacity. In fact, during handgrip testing, the increase in forearm vascular resistance (FVR) was directly related to the Nai/Ki ratio while after the exercise, FVR decrease in subjects with normal Nai/Ki and increases in those subjects with high Nak/Ki. In borderline subjects FVR at rest was inversely related to Nai but acute salt loading causes an increase in FVR proportional to Nai. These observations suggest that in subjects with borderline hypertension FVR at rest is normal perhaps as a response to a high cardiac output; however, a further hemodynamic load (salt loading) causes an increase in FVR directly related to Nai and inversely related to Ki. The study of Nai can also give useful information about the risk of developing sustained hypertension. While no subject with borderline hypertension with normal Nai developed hypertension within five years, 31% of those subjects with high Nai developed hypertension after five years.
D000328:Adult; D001143:Arousal / Q000502:physiology*; D001794:Blood Pressure; D004912:Erythrocytes / Q000378:metabolism*; D015444:Exercise; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000235:genetics; D011188:Potassium / Q000097:blood*; D012307:Risk Factors; D012964:Sodium / Q000097:blood*; D012982:Sodium, Dietary / Q000008:administration & dosage; D013315:Stress, Psychological / Q000150:complications*
D012982:Sodium, Dietary; D012964:Sodium; D011188:Potassium