Cardiovascular disease develops when arteries gradually narrow and stiffen over years or decades, usually driven by a combination of high blood pressure, unhealthy cholesterol levels, smoking, poor diet, inactivity, and chronic stress. It is the leading cause of death worldwide, responsible for roughly 19.8 million deaths in 2022, about 32% of all global deaths. The good news is that most of the factors behind it are things you can change.
What Happens Inside Your Arteries
Your arteries are lined with a thin layer of cells called the endothelium. When this lining is healthy, it keeps blood flowing smoothly, relaxes and widens arteries as needed, and prevents blood cells from clumping together. Cardiovascular disease begins when that lining gets damaged.
The damage can come from high blood pressure physically pushing against artery walls, excess cholesterol particles in the blood, high blood sugar, or chemicals from cigarette smoke. Once the lining is injured, it becomes more permeable. Cholesterol particles slip underneath it and trigger an inflammatory response. White blood cells rush in to clean up the cholesterol, but they get overwhelmed and form fatty deposits called plaque. Over time, smooth muscle cells in the artery wall multiply around the plaque, creating a hard, fibrous cap. This entire process, called atherosclerosis, can begin silently in your twenties and progress for decades before causing symptoms.
Endothelial damage is detectable before any plaque shows up on imaging. That’s why doctors focus so heavily on controlling risk factors early: by the time plaque is visible, the disease has been building for years.
High Blood Pressure
Blood pressure is the force your blood exerts on artery walls with every heartbeat. When that force stays elevated, it physically damages the endothelial lining and forces the heart to work harder than it should. Current guidelines classify blood pressure into clear categories:
- Normal: below 120/80 mm Hg
- Elevated: 120 to 129 systolic (the top number) with the bottom number still below 80
- Stage 1 hypertension: 130 to 139 systolic, or 80 to 89 diastolic
- Stage 2 hypertension: 140 or higher systolic, or 90 or higher diastolic
Hypertension rarely causes symptoms you can feel, which is why it’s often called a silent killer. Many people walk around with stage 1 or stage 2 hypertension for years without knowing it. Chronic high pressure also promotes vasoconstriction (tightening of blood vessels) and increases resistance throughout the circulatory system, accelerating plaque buildup.
Cholesterol and Blood Lipids
Not all cholesterol is harmful, but the balance matters. LDL cholesterol is the type that burrows into damaged artery walls and fuels plaque growth. HDL cholesterol helps remove excess cholesterol from the bloodstream. When LDL is too high or HDL is too low, the risk of cardiovascular disease climbs significantly.
Target LDL levels depend on your overall risk profile. For people at low risk, staying below 100 mg/dL is a common goal. For those who already have heart disease or are at very high risk of a heart attack or stroke, guidelines recommend getting LDL down to 70 mg/dL or even 55 mg/dL. Diet, exercise, and medications can all shift these numbers, but the key point is that lower LDL means less raw material available to build plaque.
Diabetes and Insulin Resistance
Diabetes roughly doubles your risk of cardiovascular disease, and the connection runs deeper than just high blood sugar. When your cells stop responding properly to insulin (a condition called insulin resistance), a cascade of harmful effects hits your arteries simultaneously.
Insulin normally helps produce nitric oxide, a molecule that relaxes blood vessels and protects the artery lining. When insulin signaling is impaired, nitric oxide drops, blood vessels tighten, and blood pressure rises. At the same time, high insulin levels act as a growth signal that causes smooth muscle cells in artery walls to multiply, thickening the walls and accelerating plaque formation. Excess blood sugar also triggers inflammation directly, activating immune pathways that further damage the endothelium.
This is why cardiovascular disease is so common in people with type 2 diabetes and even prediabetes. The arterial damage begins before blood sugar is high enough for a diabetes diagnosis.
Smoking and Tobacco Use
Smoking is one of the most potent accelerators of cardiovascular disease. The chemicals in cigarette smoke directly injure the artery lining with every inhalation, making it easier for cholesterol to penetrate the vessel wall. Smoking also raises blood pressure, increases the tendency of blood to clot, and lowers HDL cholesterol. Carbon monoxide from smoke reduces the oxygen-carrying capacity of your blood, forcing the heart to pump harder.
The damage is dose-dependent: the more you smoke and the longer you smoke, the worse the outcome. But the artery lining begins to heal relatively quickly after quitting, and cardiovascular risk drops substantially within the first few years of stopping.
Diet and Ultra-Processed Foods
What you eat shapes nearly every major risk factor for cardiovascular disease. Diets high in saturated fat raise LDL cholesterol. Excess sodium raises blood pressure. Excess calories lead to obesity, which promotes insulin resistance and chronic inflammation.
Ultra-processed foods deserve special attention. Research from the National Institutes of Health found that people with the highest intake of ultra-processed foods had a 17% greater risk of cardiovascular disease, a 23% greater risk of coronary heart disease, and a 9% greater risk of stroke compared with those who ate the least. These foods (think packaged snacks, sugary drinks, instant meals, processed meats) tend to be high in sodium, added sugars, and unhealthy fats while low in fiber and protective nutrients.
Diets centered around vegetables, fruits, whole grains, legumes, nuts, and fish consistently show the opposite pattern: lower blood pressure, better cholesterol profiles, and reduced inflammation.
Physical Inactivity
A sedentary lifestyle contributes to nearly every risk factor on this list. It promotes weight gain, raises blood pressure, worsens cholesterol ratios, and increases insulin resistance. Regular physical activity reverses all of those trends.
Current CDC guidelines recommend 150 minutes per week of moderate-intensity activity, like brisk walking, or 75 minutes per week of vigorous activity, like jogging. That breaks down to about 30 minutes a day, five days a week, for the moderate option. Exceeding those minimums provides additional cardiovascular benefit. Exercise strengthens the heart muscle, improves endothelial function, reduces inflammation, and helps control weight.
Chronic Stress
Stress is not just a feeling. It triggers a measurable biological response that, when chronic, directly promotes cardiovascular disease. Under stress, your brain’s threat-detection center signals the hypothalamus to activate the sympathetic nervous system. This causes vasoconstriction (narrowed blood vessels), higher blood pressure, a faster heart rate, and the release of stress hormones like cortisol, epinephrine, and norepinephrine.
Short bursts of this response are normal and harmless. But when stress is constant, such as from financial strain, caregiving, job pressure, or social isolation, cortisol stays elevated. Chronically high cortisol promotes fat accumulation (especially around the abdomen), raises blood pressure, and increases insulin resistance. The ongoing sympathetic activation also damages the endothelial lining, increases inflammation within arterial plaques, and makes blood more prone to clotting. These effects compound over time, making chronic psychological stress an independent contributor to atherosclerosis.
Genetics and Family History
Some people inherit a higher baseline risk for cardiovascular disease regardless of their lifestyle. In the Framingham Offspring Study, having a family history of premature heart disease (typically defined as a heart attack before age 55 in a father or brother, or before age 65 in a mother or sister) more than doubled the risk of coronary artery disease, even after accounting for traditional risk factors like cholesterol and blood pressure.
Specific genetic variations play a role. About 25% of Europeans carry two copies of a risk variant on chromosome 9p21, which is associated with a 40% increased risk of coronary artery disease generally and a twofold risk of developing it at a young age. Mutations in genes that regulate LDL cholesterol are especially significant. Familial hypercholesterolemia, caused by mutations in the gene for the LDL receptor, results in extremely high cholesterol levels from birth and dramatically accelerated plaque buildup if untreated.
Genetics don’t guarantee cardiovascular disease, but they do set the threshold. Someone with a strong family history may develop problems at lower cholesterol or blood pressure levels than someone without that genetic load, making earlier and more aggressive management of modifiable risk factors especially important.
How These Risk Factors Combine
Cardiovascular disease is rarely caused by a single factor. In most people, it results from several risk factors interacting over many years. High blood pressure damages the artery wall, making it easier for excess LDL cholesterol to accumulate. Insulin resistance amplifies both problems while adding inflammation. Smoking accelerates all of it. Inactivity and poor diet feed the underlying conditions. Stress hormones layer on additional vascular damage.
This is why two people with the same cholesterol level can have very different outcomes. The total burden of risk matters more than any single number. It also means that addressing even one or two factors, such as becoming more active and improving your diet, can meaningfully reduce the overall trajectory, even if other factors like genetics remain unchanged.