HIV is the sexually transmitted infection most clearly linked to high blood pressure. The connection works through two pathways: the virus itself drives chronic inflammation that damages blood vessels over time, and several of the medications used to treat HIV can cause weight gain that raises blood pressure. Other STIs like syphilis can damage the cardiovascular system in serious ways, but their effect on blood pressure is indirect and takes decades to appear.
How HIV Raises Blood Pressure
HIV creates a state of ongoing, low-grade inflammation throughout the body, even when the virus is well controlled with medication. This persistent inflammation stiffens artery walls over time, making them less flexible. When arteries can’t expand and contract normally, the heart has to push harder to move blood through them, and blood pressure rises. The World Health Organization now recommends integrating blood pressure monitoring directly into HIV care for this reason.
But the virus itself is only part of the story. Some of the newer HIV medications, particularly a class called integrase inhibitors, have been linked to significant weight gain and higher rates of hypertension. Research published by the American Heart Association found that people switching to newer integrase inhibitors experienced greater weight gain and increased hypertension risk compared to those on older drug regimens. Data from the RESPOND cohort, a large European study, confirmed a higher association between integrase inhibitor use and hypertension compared to other drug classes, in both people newly starting treatment and those who had been on medication for years.
This creates a difficult situation. Integrase inhibitors are highly effective at suppressing HIV and are now a cornerstone of treatment worldwide. The weight gain they can trigger, sometimes substantial, raises blood pressure through the same mechanisms it does in anyone: extra body weight increases the volume of blood the heart must pump and puts additional strain on vessel walls. For people living with HIV, managing blood pressure has become a routine part of long-term care rather than an afterthought.
What Syphilis Does to the Heart
Syphilis doesn’t raise blood pressure in the typical sense, but untreated syphilis can severely damage the cardiovascular system in ways that disrupt how blood flows. The damage happens during tertiary syphilis, the late stage that develops 10 to 30 years after the initial infection if it’s never treated.
The hallmark problem is aortitis, inflammation of the aorta (the body’s largest artery). The syphilis bacterium invades the wall of the aorta and triggers a slow inflammatory reaction that weakens and stretches the vessel. Over years, this can lead to an aortic aneurysm, which occurs in roughly half of people with cardiovascular syphilis. The ascending aorta, the section closest to the heart, is the most common site.
As the aorta stretches, the aortic valve can become leaky, allowing blood to flow backward into the heart with each beat. This forces the heart to work harder and can eventually lead to heart failure. Some people also develop narrowing of the openings where the coronary arteries branch off the aorta, which restricts blood flow to the heart muscle itself and causes chest pain. A heavily calcified ascending aorta visible on a chest X-ray is a classic sign of this damage.
These complications change blood flow dynamics and can affect blood pressure readings, particularly by widening the gap between the upper and lower numbers. But this isn’t hypertension in the way most people mean it. It’s structural heart and vessel damage that happens to show up on a blood pressure cuff.
Do Other STIs Affect Blood Pressure?
Common bacterial STIs like chlamydia and gonorrhea do not cause high blood pressure. There was early interest in whether chlamydia might contribute to atherosclerosis (the buildup of plaque inside arteries), but the research drew an important distinction. Animal studies found that a respiratory species of chlamydia could accelerate plaque buildup in cholesterol-fed mice, but the sexually transmitted species, Chlamydia trachomatis, did not. No meaningful link between common bacterial STIs and hypertension has held up.
Hepatitis B and C, which can be sexually transmitted, do cause chronic inflammation and liver damage that can indirectly affect cardiovascular health over many years. But their connection to high blood pressure is far less direct and well-documented than what’s seen with HIV.
Why the HIV Connection Matters Most
If you’re living with HIV and noticing higher blood pressure readings, the combination of chronic viral inflammation and medication side effects is the most likely STI-related explanation. The WHO now recommends that clinics treating HIV use validated automated blood pressure devices and build hypertension screening into every routine visit. Their guidelines also call for making blood pressure medications available through the same supply chains that deliver antiretroviral drugs, so people don’t have to navigate separate systems for each condition.
Weight gain from integrase inhibitors doesn’t happen to everyone, and the benefits of these drugs in controlling HIV are significant. But if your blood pressure is climbing after starting or switching medications, that’s a conversation worth having with your care team. In many cases, lifestyle changes like reducing sodium intake and increasing physical activity can offset medication-related weight gain enough to bring blood pressure back toward a healthy range. When they can’t, adding a blood pressure medication is straightforward and effective.
For syphilis, the takeaway is different. Cardiovascular damage from syphilis is almost entirely preventable with early treatment. A simple course of antibiotics during the early stages of infection eliminates the bacterium long before it can reach the aorta. The 10-to-30-year window before cardiovascular symptoms appear means that routine STI screening catches most cases in time.