High sodium (HS) diets have been linked to an increased risk for cardiovascular disease (CVD). Blood pressure reactivity (BPR) is a strong predictor of future CVD events and has been shown to increase with HS intake. In general, men are shown to have a greater BPR while women appear to have a greater BPR under HS conditions. Potassium (K+) is shown to have blood pressure (BP) lowering effects however its influence on BPR remains unclear. We sought to determine the effect of K+ supplementation (KS) on BPR under HS conditions in healthy, normotensive men and women. We hypothesized that women would be more responsive to the benefits of KS on BPR under HS compared to HS alone. Nineteen participants (13W/6M, 27±4 years, BMI 25±3 kg/m 2 , BP 111±9/68±9 mmHg) completed three 10-day controlled diets in random order: a moderate potassium/low sodium (MK/LS, 55mmol/50mmol), a moderate potassium/high sodium (MK/HS, 55mmol/300mmol), and a high potassium/high sodium (HK/HS, 120 mmol/300 mmol) diet. K+ intake was increased using potassium chloride capsules. Placebo capsules were administered during the MK diets. 24-hour BP measurements and urine collections were completed on day 9. On day 10, BPR was assessed by measuring the change in mean arterial pressure (∆MAP) in response to isometric handgrip exercise (IHG) at 40% of maximal voluntary contraction with post-exercise ischemia (PEI) and the cold pressor test (CPT). Repeated measures ANOVA, mixed-effect model, and Tukey’s post-hoc analysis were conducted to assess sex and diet differences. Urinary sodium excretion was greater on the MK/HS and HK/HS than the MK/LS (both p< 0.0001) and urinary potassium excretion was greater on the HK/HS than the MK/LS and MK/HS (both p< 0.01), confirming diet compliance. No differences were observed between men and women in 24-hour MAP during the MK/LS and HK/HS diets. However, during the MK/HS diet, men exhibited a higher 24-hour MAP than women (82±1 mmHg vs. 78±5 mmHg, p=0.03). There were no significant effects of sex (p=0.08), diet (p=0.69), or their interaction (p=0.057) on ∆MAP during IHG. However, women had a lower ∆MAP on the MK/LS (22±12 mmHg vs. 35±5 mmHg, p=0.006) and MK/HS (21±11 mmHg vs. 34±10 mmHg, p=0.03) diets while no difference between men and women was seen on the HK/HS diet (p=0.84). Additionally, there were no significant effects of sex (p=0.37) or diet (p=0.76) on ∆MAP during PEI, however there was trend for an interaction (p=0.052), driven by a greater response in men on the MK/LS diet (27±4 mmHg vs.18±11 mmHg p=0.02). Lastly, there were no significant effects of sex (p=0.16), diet (p=0.98), or their interaction (p=0.51) on ∆MAP during CPT. These data suggest men may have a greater BPR to IHG under both LS and HS conditions compared to women that was not present with KS. These preliminary data suggest further examination of sex specific responses to varying levels of sodium and potassium is warranted. Funding source: NHLBI R01 HL145055 This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Irwin et al. (Fri,) studied this question.