High Salt Intake Benefits Patients with Postural Tachycardia Syndrome

In this crossover study, researchers enrolled 14 patients with POTS and 13 healthy control persons and examined them over a period of 6 days with a low-sodium diet (10 mEq sodium per day) or a high-sodium diet (300 mEq sodium per day). They measured the supine and standing heart rate, blood pressure, serum aldosterone, plasma renin activity, blood volume, and plasma norepinephrine and epinephrine levels.

Key findings of the study were:

• Among the POTS patients, the researchers found that the HS diet reduced upright heart rate and Δ heart rate compared with the LS diet.
• They also found that total blood volume and PV increased, and standing norepinephrine decreased with the HS compared with the LS diet.
• However, they noted that upright heart rate, Δ heart rate, and upright norepinephrine remained higher in POTS patients than in healthy control subjects on the HS diet, despite no difference in the measured PV.

POTS Group:

» Upright heart rate: median 117 beats/min,

» Δ heart rate: 46 beats/min,

» Upright norepinephrine levels: 753 pg/ml.

Healthy Control Group:

» Upright heart rate: 85 beats/min

» Δ heart rate: 19 beats/min,

» Upright norepinephrine levels: 387 pg/ml.

The authors concluded, "In POTS patients, high dietary sodium intake compared with low dietary sodium intake increases plasma volume, lowers standing plasma norepinephrine, and decreases Δ heart rate. "

For further information:

https://www.jacc.org/doi/10.1016/j.jacc.2021.03.005