Kidneys and blood pressure: how they are connected

Your kidneys and blood pressure sit in a surprisingly close relationship, and it works both ways. High blood pressure can strain your kidneys over time, while poorly working kidneys can drive blood pressure up. Alongside diabetes, high blood pressure is one of the best-known factors behind reduced kidney function (Bidani 2004).

This article expands on the overview about your kidney function, focusing on the link between kidneys and blood pressure.

How do your kidneys regulate blood pressure?

Your kidneys play a key role in blood pressure. They regulate how much fluid and salt your body holds, which helps set the volume in your blood vessels. They also make substances that can narrow or widen vessels, fine-tuning pressure like a thermostat. When that system works less well, blood pressure can drift out of balance. So your kidneys are not just a filter but also a regulator.

How does high blood pressure strain your kidneys?

Lasting high blood pressure puts the small vessels in your kidneys under pressure. Those vessels are fine and vulnerable, and years of overpressure can slowly damage them, so filtering can gradually decline. The frustrating part is that it happens quietly: both high blood pressure and mildly reduced kidney function often cause no symptoms for a long time.

The vicious circle between kidneys and blood pressure

That sounds gloomy, but the circle is not inevitable, and many people keep both stable for years. The insight mainly helps you watch both together rather than separately.

Which blood values give insight?

To see how your kidneys are doing alongside your blood pressure, creatinine and eGFR are the core values. They show how well your kidneys filter, which is exactly what high blood pressure can affect over time (Webster 2017). Read more at high creatinine and eGFR explained. See also creatinine.

What can you do?

If you have high blood pressure and want a view of your kidney function, you can have a kidney function test at Vitalcheck without a referral, capturing creatinine and eGFR at once. If a value is off, discuss it with your GP, who looks at your blood pressure and kidney values together. Do not change blood pressure medication without consulting your GP.

References

• Bidani AK, Griffin KA. Pathophysiology of hypertensive renal damage: implications for therapy. Hypertension. 2004. PMID: 15452024.
• Webster AC, et al. Chronic Kidney Disease. Lancet. 2017. PMID: 27887750.
• RIVM. High blood pressure.

Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.