Q: Is there a relationship between my blood pressure levels and my blood sugar levels?
A: This is a serious and important question that often gets lost in the fray of multiple providers delivering fragmented care for a person with multiple conditions. The short answer is absolutely ‘Yes’! Now, let’s unpack this relationship so you can advocate for your best healthcare outcomes.
How Your Body Regulates Glucose
Let’s first review some basics about blood sugar (glucose). The glucose in your blood serves as a primary source of energy for all the cells in your body. There are other molecules your body can make for fuel if needed, like ketones, but we’ll keep the focus on glucose here for simplicity.
Your body has sensors throughout it to determine if you are at the correct blood glucose level. In people without diabetes, this level is typically between 70 and 120 mg/dL (milligrams per deciliter). There are multiple hormones that either activate or go quiet as needed to protect this glucose level. If the level goes too low, your body might release catecholamine hormones (commonly known as adrenalin hormones) to trigger an increase in the level of glucose in the blood. If blood glucose goes too high, your body will release insulin and other hormones to correct the level back down to an appropriate range.
People with diabetes don’t lose the ability to raise or lower their blood sugar levels; rather, the hormones that serve to keep blood glucose in the correct range don’t function correctly, and the sensors that assess the glucose level are also often impaired.
How Your Body Regulates Blood Pressure
A similar set of processes apply to maintaining a healthy blood pressure level. In many ways, keeping your blood pressure in a good range is even more critical than keeping your blood glucose in a good range. Your body has a myriad of ways to “make” more blood sugar as well as making alternative sources of energy like ketones. But we don’t have any way to “make” more blood pressure. The body can protect blood glucose levels much better than it can protect blood pressure. If we are experiencing low blood volume, we can’t add more instantly. If we don’t have enough blood, we will pass out and this is very dangerous to the brain and body long term.
With limited options for raising blood pressure, the body relies on the same hormones that get activated when blood glucose is low—catecholamine, or adrenalin, hormones—to affect this change. Catecholamines tighten up our blood vessels, making it harder for the heart to pump the blood through our arteries, which raises blood pressure.
If blood pressure is too high, on the other hand, the body wants to remove blood in order to reduce the overall volume in our vessels and make it easier for the heart to pump the blood through our arteries. To accomplish this, nitric oxide is released to expand (dilate) blood vessels and reduce the pressure against our heart. When the blood vessels in the kidney expand, it causes them to release more water in order to lower blood pressure. This effect is known as diuresis, or the removal of fluid. These are just a few of the ways that we have to control blood pressure, and they are the most common.
People with hypertension, a condition in which blood pressure is elevated, don’t lack the ability to control their blood pressure. But like the person with diabetes, their sensors are impaired and their response to high or low blood pressure isn’t always on the mark.
How Blood Sugar Affects Blood Pressure
How are these two systems connected? Insulin, which plays a role in managing blood glucose, has an unfortunate relationship with nitric oxide production in blood vessels. It blocks the ability of the body to make nitric oxide. Nitric oxide is important to blood vessels because it is one of the very few ways to expand the size of the blood vessels and lower blood pressure. If a person with diabetes is using insulin, this severely impairs the ability of the body to lower blood pressure via nitric oxide production, in turn increasing the risk of high blood pressure.
In situations where the blood pressure is too low, the catecholamine response described above doesn’t discriminate, and blood sugar will also rise as a result. The same is true if the blood sugar goes too low; the catecholamine response is the first thing that the body uses to compensate, and this will raise blood pressure in the aftermath. This is how low blood sugar or low blood pressure can cause the other to go high. It is important to realize that some medications that lower blood pressure or blood glucose will override any natural protections you have and trigger these events as well.
Bottom line: If you are living with diabetes, high blood pressure, or both, it’s important to closely monitor BOTH your blood sugar and your blood pressure in tandem to avoid harming one when you treat the other.
Endocrinologist and Chief Executive OfficerEndocrinology Associates, Inc., Columbus, Ohio
Dr. Elena Christofides practices endocrinology at Endocrinology Associates in Columbus, Ohio, and also runs an independent research facility, Endocrinology Research Associates. She holds dual board certifications in Endocrinology, Diabetes, and Metabolism and Internal Medicine and several academic positions, including Adjunct Assistant Professor at Ohio State University College of Medicine and Clinical Associate Professor, Core Group IV, Endocrinology at Ohio University College of Medicine.