How Insulin Causes High Blood Pressure
Good morning guys!
Imagine a man named John. He’s in his 40’s and is always busy with work. He’s got 3 young kids ages 6,10, and 12. John loves a good burger and fries and a few beers on a Friday night but in general, tries to be mindful with more of his meals these days. After all, he isn’t getting any younger.
He’s even managed to drop 5 lbs over the last month with a few changes to his diet while walking more. He’s feeling a bit nervous this morning. He’s currently waiting for his Doctor to enter the room for his annual check up. He knows he carries a bit of extra weight around his belly, but for the most part, he’s in okay shape. Especially compared to some of the other dads he sees at his oldest son’s baseball games.
“I would recommend we start a blood pressure medication” says the doc.
John feels his heart sink.
“Really.." He thinks to himself: “A blood pressure medication? But how did this happen? I weigh the same as what I did last year. And if anything, I’m actually eating a little better. And I’ve been even more intentional about limiting salt in my diet.”
This encounter happens to 100s of people everyday. And it can be frustrating. The reality is that high blood pressure is a symptom. A dangerous symptom that causes other symptoms. But the actual cause of high blood pressure is often a deeper problem. And while there are multiple potential causes, none in my opinion is greater than insulin resistance.
What is insulin resistance?
Insulin is a hormone produced by the pancreas that helps regulate our blood sugar levels. It is the “key” that opens the door to allow sugar into your muscle and fat cells to be used for energy. However, in some cases, our bodies become resistant to the effects of insulin. This means that even though insulin is present, our cells don't respond to it as effectively as they should. So what happens next?
Think of it like the lock on the door becomes rusty so the key (insulin) doesn’t work properly. The rusty locks are jammed and don’t open easily. The body recognizes that the doors aren’t opening. And even though the problem is with the locks, it responds by releasing more insulin (more keys) to try to open the doors. The result? Excess insulin in the system (hyperinsulinemia).
What causes insulin resistance over time?
Going back to our story earlier, John just found out he has high blood pressure. But he isn’t sure how this happened. Especially because nothing has really changed in his lifestyle in the past year. That’s the interesting part.
Insulin resistance is something that is slowly developing beneath the surface. And it isn’t until it’s advanced far enough that you start to see other symptoms emerge. Let me briefly explain.
In John’s case, his body has been producing more insulin over time and it’s kept his blood sugar stable. So when he has his typical check ups, his numbers have been consistent. He’s always had normal blood sugar and normal blood pressure. But the longer this process goes on, the more insulin his body produces. As his body produces more insulin to unlock the doors to his cells, his blood sugar remains normal. But his insulin levels are not. The problem is no one has been testing his insulin levels.
The reality is that number has likely been climbing year after year undiagnosed. So while most of his biomarkers were okay, the true state of his health was slipping. And it can often take years for insulin resistance to become significant enough to affect blood sugar or blood pressure to the point of actually being detected when insulin isn’t directly measured.
How does insulin cause hypertension?
Here’s the meat of today’s message. You’ve likely heard that salt is bad. But why? How? Is that even true? The reality is much more complex. In fact, more people are hospitalized every year for having too little sodium in their bloodstream compared to too much. So what gives?
There’s a lot to unpack but for the sake of today’s email we’ll focus on why it matters in regards to insulin. And why insulin matters for hypertension.
To put it simply, where there is more sodium, water will follow. This matters because when there are high amounts of sodium in your cells, your body will respond by holding onto more water. When you hold onto more water, you have more fluid retention in your blood vessels. When there is more fluid to push around in a fixed space, the pressure is greater. For example, if you only open the spigot of the hose partially, the pressure coming out the end of the hose will be minimal. If you open the spigot wide open there is more fluid and therefore more pressure in the fixed space of the hose.
That’s great. But what does it have to do with insulin? In normal conditions, your body can do a good job of excreting sodium, even if you are ingesting higher amounts of it. To put it simply, the more sodium you ingest, the more you pee out. But insulin acts on tubules in your kidneys to cause more sodium retention. So now you are holding onto more sodium than you otherwise would. And this can be the case regardless of how much sodium you are eating. Which is why in many cases, simply reducing salt intake doesn’t solve the hypertension. Because higher salt levels in the blood is a symptom of hyperinsulinemia.
Another Consequence Of High Insulin
In summary, more insulin causes more sodium retention which causes more water retention which leads to greater blood pressure. But that’s only one way that insulin resistance causes hypertension. Here’s another: Increased vasoconstriction of your blood vessels.
Insulin directly and indirectly leads to the smooth muscle lining of your blood vessels constricting. Taking the hose example again, this is like the hose suddenly becoming smaller while the same amount of water is trying to flow through it. The result? Higher blood pressure.
This happens because of insulin’s role in activating your “fight or flight” sympathetic nervous system. If you needed to run from a bear to survive, you’d want your blood pressure to be high. Most of us don’t need to do that in our day to day lives (I hope) but in many cases, our sympathetic nervous system is still overactivate because of too much insulin. More on this at another time.
At the same time that there is an increase in vasoconstriction because of the sympathetic response, there is a corresponding inhibition to the natural vasodilation response. Nitric oxide (NO) is a compound that naturally exists in the body. It is responsible for causing the blood vessels to dilate to lower blood pressure. Insulin works to inhibit the normal mechanism of NO. This results in the lack of vasodilation. So in combination with causing vasoconstriction via the sympathetic nervous system and REDUCING vasodilation via the inhibition of NO, the result is MORE Vasoconstriction = Greater Blood pressure.
Combine greater vasoconstriction with greater fluid retention in the kidneys and it becomes quite clear that insulin resistance is a much greater threat as the source of hypertension in many cases than simply blaming salt. Too often we blame salt for what insulin resistance did. And since sodium retention is more of a symptom than a cause, we are never actually treating the root of the problem.
This is lucrative for drug companies, but not ideal for you or your health. Improving metabolic health is the foundation of our Brother2Brother program. We’ve done a deep dive into the causes and action steps for insulin resistance in the past, so i’ll spare you the time today. But as you can see, hypertension is a complex topic.
Next in this series we’ll cover some of these areas deeper including rebalancing nervous system's stress response, balancing electrolytes, and ways to naturally improve vasodilation. All of these play a factor in blood pressure and are things we can influence with our lifestyle.
Until then,
Brett Boettcher
Brother2Brother
P.S. “What does a nosey pepper do? … It get’s jalapeño business.”
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