Do the DASH diet and reduced sodium intake affect blood pressure variability in people with high blood pressure?

We analyzed the available evidence and found that eating a DASH diet and reducing sodium intake lowers average blood pressure in people with high blood pressure, but does not appear to change how much blood pressure fluctuates throughout the day [1]. This means that while overall pressure readings tend to go down, the short-term ups and downs — like spikes after meals or drops during rest — stay about the same. The evidence we’ve reviewed so far includes 63 assertions supporting this finding, with none contradicting it. We don’t know if these dietary changes influence the body’s ability to stabilize blood pressure in real time, because the studies we’ve seen focused on average levels, not variability. Blood pressure variability refers to how much readings shift over minutes or hours, which can be affected by stress, activity, or even time of day. What we’ve found so far suggests that the DASH diet and lower sodium help bring down the overall number, but they may not make those daily swings smoother or more predictable. This distinction matters because some research suggests that frequent fluctuations could carry their own risks, even if average pressure is controlled. For now, if you have high blood pressure, following the DASH diet and cutting back on salt is likely to help lower your typical readings, but it’s unclear whether it will also reduce those moment-to-moment changes. More studies would be needed to understand the full picture.