About 23% of U.S. adults ages 18 to 39 have high blood pressure, yet only about 14% of that group is being treated for it. That gap matters because high blood pressure in your twenties and thirties rarely announces itself with obvious symptoms. The causes range from everyday habits to hidden medical conditions, and understanding them is the first step toward getting your numbers under control.
What Counts as High Blood Pressure
The thresholds are the same regardless of age. Stage 1 hypertension starts at a systolic reading (the top number) of 130 to 139 or a diastolic reading (the bottom number) of 80 to 89. Stage 2 hypertension is 140/90 or higher. These numbers are based on averages taken in a clinical setting, not a single reading on a stressful day. If your systolic and diastolic fall into two different categories, the higher category is the one that applies.
Secondary Causes Are More Common in Younger People
When someone under 40 has confirmed high blood pressure, a treatable underlying condition is responsible roughly 30% of the time. That’s a much higher rate than in older adults, where the cause is more often a gradual stiffening of arteries over decades. A study of over 2,000 hypertensive patients ages 18 to 40 found that the most common hidden cause was a condition called primary aldosteronism, accounting for about 55% of secondary cases. In this condition, the adrenal glands produce too much of a hormone that tells the kidneys to hold onto salt and water, which drives blood pressure up.
The second most common cause was narrowing of the arteries that supply the kidneys, responsible for about 18% of secondary cases. In younger adults, this narrowing is often caused by fibromuscular dysplasia, a condition where the artery wall thickens in an unusual pattern, rather than the fatty plaque buildup more typical in older people. Kidney disease itself accounted for about 13% of cases, and tumors of the adrenal glands that pump out excess adrenaline made up about 6%.
Other conditions that can quietly raise blood pressure in young adults include thyroid disorders (both overactive and underactive), a congenital narrowing of the aorta called coarctation, and overactive parathyroid glands that raise calcium levels in the blood. These are all fixable or manageable once identified, which is why thorough testing matters when a young person’s blood pressure is persistently high.
Diet, Especially Ultra-Processed Food
A large review pooling data from over 8 million adults found that every additional 100 grams per day of ultra-processed food was linked to a 14.5% higher risk of developing hypertension. For context, 100 grams is roughly one serving of instant noodles, a couple of packaged snack bars, or a few slices of deli meat. The connection runs through multiple pathways: these foods tend to be loaded with sodium, added sugars, and industrial fats while being low in potassium and fiber, all of which influence blood pressure regulation.
Young adults eat more ultra-processed food than any other age group. Convenience, cost, and time pressure all play a role. The effect is cumulative. Years of a diet built around packaged and fast food can shift your baseline blood pressure upward well before middle age.
Energy Drinks and Vaping
Energy drinks are a particular concern for this age group. A Mayo Clinic study found that a single energy drink raised systolic blood pressure by about 6%, compared to 3% with a placebo. That spike is temporary, but for someone drinking one or two a day, the repeated surges can contribute to sustained elevation over time, especially when combined with other risk factors.
Vaping delivers a similar hit. Research using a randomized crossover design showed that inhaling from a nicotine-containing e-cigarette produced a “marked and sustained” rise in arterial blood pressure, while a nicotine-free placebo e-cigarette produced no effect at all. The blood pressure increase was driven entirely by the nicotine, not by the other solvents in the vapor. This confirms that switching from cigarettes to vaping doesn’t remove the blood pressure risk that comes with nicotine.
Sleep Apnea in Young Adults
Sleep apnea isn’t just a condition that affects middle-aged, overweight men. Young adults with sleep apnea had a 45% higher prevalence of hypertension compared to those without it, even after researchers adjusted for other factors like weight and smoking. The link was actually stronger in younger adults than in older ones.
When breathing stops repeatedly during sleep, oxygen levels drop, and the nervous system responds by tightening blood vessels. Over months and years, this nightly stress remodels the cardiovascular system. Obesity is the strongest risk factor for developing sleep apnea, but it can also occur in people at a normal weight, particularly those with certain jaw or airway structures. If your blood pressure is high and you snore heavily, wake up feeling unrefreshed, or experience daytime fatigue, sleep apnea is worth investigating.
Chronic Stress and Its Physical Toll
Early-career stress, financial pressure, and anxiety aren’t just emotionally draining. They produce measurable cardiovascular effects. Research on work stress found that chronically stressed individuals had higher heart rate reactivity on stressful days, elevated systolic blood pressure, and reduced vagal tone, which is the body’s built-in braking system for calming the heart.
When vagal tone is low, the heart runs faster and blood pressure stays higher than it should at rest. Prospective studies have found that a faster resting heart rate and lower vagal tone actually precede the development of hypertension, suggesting that years of unmanaged stress can prime the cardiovascular system for sustained high blood pressure. This doesn’t mean stress “causes” hypertension in isolation, but it amplifies every other risk factor on this list.
COVID-19 and New-Onset Hypertension
A notable wave of new high blood pressure diagnoses has followed the COVID-19 pandemic. Among people hospitalized with COVID, about 21% who had no prior history of hypertension developed it during their hospital stay. At six-month follow-up, persistent hypertension appeared in roughly 20.6% of hospitalized COVID patients and 10.85% of those who were not hospitalized. Both groups were significantly more likely to develop lasting high blood pressure than people who had the flu instead, with hospitalized COVID patients facing more than double the risk.
The mechanisms likely involve the virus’s ability to trigger intense inflammation and disrupt the hormonal system that regulates blood pressure. Whether these effects are permanent or gradually resolve is still being tracked, but if your blood pressure climbed after a COVID infection and hasn’t come back down, it’s worth monitoring rather than assuming it will correct itself.
Genetics and Family History
Having one or both parents with high blood pressure raises your own risk substantially, and it tends to show up earlier. Genetic predisposition influences everything from how your kidneys handle sodium to how your blood vessels respond to stress hormones. You can’t change your genes, but knowing your family history helps you and your doctor decide how aggressively to track and manage your blood pressure starting in your twenties rather than waiting until routine screening picks it up in your forties.
Some rare genetic conditions cause hypertension directly in young people, including certain syndromes that affect the aorta or the adrenal glands. These are uncommon but worth screening for when blood pressure is severely elevated at a young age or doesn’t respond to standard treatment.
Why It’s Often Missed
Young adults visit doctors less frequently than any other adult age group. When they do, blood pressure may be checked but a mildly elevated reading is sometimes dismissed as white-coat anxiety. The low treatment rate, just 14% among 18-to-39-year-olds with hypertension, suggests that many cases are either undiagnosed or not taken seriously. Because secondary causes are responsible for nearly a third of cases in this age group, a single “watch and wait” approach can mean years of untreated damage to the heart, kidneys, and blood vessels from a condition that might have been correctable all along.