Background: Dietary sodium influences intermediate physiological traits in healthy adults independent of changes in blood pressure. The purpose of this study was to test the hypothesis that dietary sodium affects cardiac autonomic modulation during mental stress.
Method: In a prospective, randomized cross-over design separated by 1 month between diets, 70 normotensive healthy young adults (F/M: 44/26, aged 18-38 years) consumed a 5-day low (10 mmol/day), normal (150 mmol), and high (400 mmol) sodium diet followed by heart rate variability (HRV) recordings at rest and during 5-min computerized mental arithmetic.