Are Energy Drinks Bad for Blood Pressure?

Energy drinks raise blood pressure in nearly every controlled study that has tested them, and the increase is not trivial. A large meta-analysis of randomized trials found that a single energy drink can push systolic blood pressure up by roughly 4 to 5 mmHg for over an hour, with diastolic pressure following a similar pattern. That bump may sound small, but it is larger than what caffeine alone produces at equivalent doses, and it stacks on top of whatever your resting pressure already is. The story gets more complicated when you factor in arterial stiffness, sympathetic nervous system activation, and the wide variation in how different people metabolize these drinks.

How Much Does a Single Energy Drink Raise Blood Pressure?

The short-term spike is well documented. A systematic review and meta-analysis of randomized clinical trials found that energy drink consumption raised systolic blood pressure most sharply at around 60 to 80 minutes after drinking, with an average increase of about 4.7 mmHg. Diastolic pressure peaked a bit later, around the two-hour mark, climbing roughly 4.5 mmHg above baseline.¹ That meta-analysis pooled data from multiple trials, so the numbers represent a fairly reliable average across healthy adults.

Individual trials paint a consistent picture. In one randomized trial, a single energy drink raised systolic blood pressure by about 6% compared to a 3% increase from a placebo drink, while diastolic blood pressure rose roughly 7% versus essentially no change with placebo.² Another randomized trial using a high-volume energy drink (32 ounces, which is on the larger side of what you would grab at a convenience store) found statistically significant increases in both peripheral and central blood pressure compared to placebo.³

For a healthy young person with normal blood pressure, a temporary jump of 4 to 7 mmHg may not matter much. But if you already have elevated pressure, if you are on medication that interacts with stimulants, or if you are about to do something physically demanding, that margin shrinks. Blood pressure is not a number with a lot of room for error at the upper end of the range.

It Is Not Just the Caffeine

One of the most consistent findings in this research is that energy drinks raise blood pressure more than caffeine alone does, even when the caffeine content is matched. A study comparing energy drink supplementation to an equivalent dose of caffeine measured ambulatory blood pressure over a full 24-hour period and found that average systolic pressure was about 6 mmHg higher during the energy drink phase than the caffeine-only phase. Diastolic pressure showed a similar gap of about 5 mmHg.⁴ The energy drink also raised nighttime blood pressure loads more than caffeine did, which matters because your blood pressure normally dips while you sleep, and losing that dip is associated with higher cardiovascular risk over time.

Another trial found that while both an energy drink and caffeine raised systolic blood pressure in the first couple of hours, the energy drink kept pressure elevated at the six-hour mark, when the caffeine-only group had returned to baseline.⁵ So it is not simply a matter of how much caffeine is in the can. Something else in the formulation prolongs and amplifies the effect.

What that “something else” is remains partly unresolved. A review of the evidence concluded that cardiovascular responses to energy drinks are best explained by caffeine and sugar acting together, with little proven influence from other ingredients. But the same review noted that a role for taurine and glucuronolactone could not be ruled out.⁶ Taurine is an interesting case because, taken alone, it tends to lower blood pressure. Yet when combined with caffeine, one study found the pair actually raised mean arterial blood pressure while slowing heart rate.⁷ A later review suggested that taurine should theoretically counteract some of caffeine’s cardiovascular effects, but acknowledged the interaction has not been fully worked out in humans.⁸

Guarana, another common ingredient, adds to the complexity. It contains its own caffeine, so an energy drink listing “caffeine” and “guarana extract” on its label may deliver more total caffeine than the label’s caffeine figure suggests. One review noted that guarana may have a synergistic caffeine-like effect on top of the caffeine already present, though the combined cardiovascular impact still needs more study.⁹

What Happens to Your Arteries

Blood pressure is just one measure of cardiovascular stress. Energy drinks also appear to stiffen the aorta, the body’s largest artery. A study in healthy young men found that two hours after consuming an energy drink, central arterial stiffness (measured by pulse wave velocity) increased significantly compared to baseline, while the placebo group showed no change at all.¹⁰ Stiffer arteries mean the heart has to work harder to push blood through, and chronic stiffness is a well-established risk factor for cardiovascular disease.

There is also evidence on how energy drinks affect the inner lining of blood vessels. One study found that flow-mediated dilation, a standard measure of how well blood vessels relax in response to increased blood flow, dropped from about 5.9% at baseline to 1.9% after an energy drink.¹¹ A separate study confirmed a similar pattern, with flow-mediated dilation declining from 5.1% to 2.8% after consumption.¹² When blood vessels cannot dilate properly, they are less able to buffer sudden spikes in pressure or deliver blood efficiently to tissues under demand.

The picture is not entirely one-sided, though. One trial tested multiple brands individually and found that Red Bull and 5-hour Energy actually improved endothelial function at four hours, while NOS and coffee did not change it. The researchers noted that caffeine did not appear to be the ingredient responsible for the differences between brands.¹³ This is a good reminder that “energy drinks” are not a single product. Formulations vary widely, and the cardiovascular impact of one brand may not match another.

Why Your Nervous System Overreacts

The blood pressure spike from energy drinks appears to be driven at least partly by ramped-up sympathetic nervous system activity. One study measured plasma norepinephrine, a hormone released during the body’s fight-or-flight response, and found that it jumped roughly 74% after an energy drink versus about 31% after a placebo. Normally, when blood pressure rises, the body reflexively dials back sympathetic output to bring it down. That did not happen with the energy drink; both blood pressure and norepinephrine went up together.¹⁴

Another study on Red Bull found that blood glucose and catecholamine levels (the family of hormones that includes adrenaline and norepinephrine) rose significantly after consumption, confirming heightened sympathetic activity both at rest and during exercise.¹⁵ A review of the broader literature reinforced the finding that energy drink consumption is accompanied by increases in blood pressure, sympathetic drive, and also QT prolongation on ECG.¹⁶

This is one of the reasons energy drinks feel different from a cup of coffee even at similar caffeine loads. The sympathetic activation is stronger and the normal feedback loop that should bring things back to baseline gets partially overridden. For most healthy people, this resolves within a few hours. For someone with an underlying tendency toward arrhythmia or hypertension, overriding that feedback loop is a less benign proposition.

Energy Drinks and Exercise

A lot of people drink energy drinks before a workout or a sports event, which is exactly the context where the blood pressure effect becomes most relevant. A meta-analysis of randomized controlled trials looking specifically at cardiovascular responses during exercise found that energy drinks raised systolic blood pressure by about 9 mmHg during physical activity compared to controls.¹⁷ Heart rate also went up, but by a more modest 3 beats per minute. The authors highlighted that the systolic increase during exercise is particularly worth noting for anyone already prone to hypertension, since exercise itself raises blood pressure and stacking an energy drink on top amplifies the peak.

If you are lifting heavy or sprinting, your systolic pressure can transiently reach well above 200 mmHg even without chemical assistance. Adding another 9 mmHg to that peak pushes the ceiling higher in a setting where your cardiovascular system is already under maximal stress. For competitive athletes undergoing regular cardiac screening, this is likely manageable. For someone who only exercises sporadically and has undiagnosed high blood pressure, it could be a different story.

Children and Adolescents

Kids and teenagers are a population of particular concern because their cardiovascular systems are still developing and because they tend to consume energy drinks in social or recreational contexts without much thought to dosing. A randomized trial in children and adolescents found that a single bodyweight-adjusted energy drink raised 24-hour systolic blood pressure by about 5 mmHg and diastolic pressure by about 3.5 mmHg compared to placebo. The elevation persisted through both daytime and nighttime readings, and the prevalence of diastolic readings in the hypertension range was significantly higher during the energy drink period.¹⁸

A systematic review echoed the concern, noting that energy drink consumption in children and adolescents has been linked to increased blood pressure and altered heart rhythms, and could exacerbate developmental cardiovascular issues.¹⁹ The fact that the pediatric trial used a bodyweight-adjusted dose (not just handing a kid an adult-sized can) makes the result more striking. Even a proportionate amount was enough to shift 24-hour pressure readings upward.

Sugar-Free Versions Raise Blood Pressure Too

If you assumed sugar-free energy drinks would be gentler on blood pressure, the data says otherwise. A study compared regular Red Bull, sugar-free Red Bull, water with caffeine, and water with placebo. Regular Red Bull, sugar-free Red Bull, and caffeine water all raised blood pressure by the same amount, roughly 3 to 4 mmHg, and all were significantly higher than the placebo water.²⁰ The sugar-free version was no better from a blood pressure standpoint. Sugar may contribute to some metabolic and cardiovascular effects over the long term, but for the acute pressure spike, caffeine and the other active ingredients are doing the heavy lifting regardless of whether the drink has sugar.

Mixing Energy Drinks with Alcohol

Combining energy drinks with alcohol introduces a separate layer of risk. The cardiovascular concern is compounded by a behavioral one: a review of the evidence found that consuming alcohol mixed with energy drinks leads to decreased perceived intoxication, increased stimulation, and increased desire to keep drinking compared to alcohol alone.²¹ In other words, the energy drink masks how drunk you feel without actually reducing the alcohol’s effects on your body. That means you are more likely to drink more, which further raises blood pressure (alcohol itself is a well-known short-term pressor), while also impairing the judgment you would need to recognize that your cardiovascular system is being stressed from both directions.

Why Individual Responses Vary So Much

Not everyone who drinks an energy drink experiences the same blood pressure increase, and genetics is one reason. The CYP1A2 gene determines how quickly your liver breaks down caffeine. People who carry the slower-metabolizing variant (AC genotype) had higher post-caffeine systolic blood pressure than those with the fast-metabolizing variant (AA genotype), and caffeine raised systolic pressure only in the slower metabolizers.²² Physical activity and habitual caffeine consumption also modified the response, making the picture even more individual.

A separate trial looking at genetic polymorphisms and habitual caffeine intake found that caffeine raised blood pressure across the board, but the magnitude differed with genotype. Among people who consumed 90 mg or less of caffeine daily (roughly one cup of coffee), those with the CYP1A2 CC variant saw their systolic pressure rise by about 12 mmHg after caffeine, compared to about 4 mmHg in the AA/CA group.²³ If you are a slow metabolizer who does not regularly drink caffeine, an energy drink could push your blood pressure up three times more than it pushes up your friend’s. You would have no way of knowing without genetic testing or at least a pattern of sensitivity.

What About Chronic, Long-Term Use?

Nearly all of the strong evidence on energy drinks and blood pressure comes from acute studies: drink the product, measure what happens over the next several hours. The chronic picture is far less clear, and what little data exists is surprisingly reassuring. A study specifically designed to look at chronic high energy drink consumption in adolescents found no significant or clinically relevant differences in any cardiological parameters, including heart rate, between habitual heavy consumers and a control group.²⁴

That result should be interpreted cautiously. It does not mean long-term energy drink use is safe for your cardiovascular system; it means the study did not detect structural or resting-state heart damage in habitual users at the time of measurement. Adolescents have robust cardiovascular reserve, and cumulative damage from repeated blood pressure spikes, endothelial dysfunction, and arterial stiffening might not show up as measurable disease for years or decades. Absence of evidence in a young population over a limited timeframe is not the same as evidence of absence over a lifetime.

The QT Interval Problem

Blood pressure is not the only cardiac parameter energy drinks affect. The QT interval, which reflects the time it takes the heart’s electrical system to reset between beats, gets measurably longer after energy drink consumption. A randomized trial found that the corrected QT interval was significantly more prolonged in the energy drink group than in the caffeine-only group at two hours, and the energy drink also kept systolic blood pressure elevated at six hours when caffeine had worn off.⁵ A separate high-volume trial confirmed statistically significant QT prolongation compared to placebo.³

QT prolongation matters because it increases the risk of abnormal heart rhythms, some of which can be life-threatening. In healthy people with normal baseline QT intervals, the prolongation seen in these trials is modest and transient. But for anyone with a pre-existing long QT syndrome (which can be inherited and undiagnosed), taking medications that also prolong the QT interval (a long list that includes certain antibiotics, antidepressants, and anti-nausea drugs), or combining energy drinks with other stimulants, the additive effect on heart rhythm becomes a real concern. The blood pressure spike and the QT prolongation happen simultaneously, which means the heart is dealing with both a higher workload and an electrical timing disruption at the same time.

Central Blood Pressure and Why It Matters

Most blood pressure readings come from a cuff on your arm, which measures peripheral pressure. Central blood pressure, the pressure inside your aorta near the heart, is actually a better predictor of cardiovascular events. One study found that a caffeinated energy shot raised central systolic blood pressure by about 8 mmHg compared to about 1.5 mmHg with a noncaffeinated version at three hours post-consumption.²⁵ That is a meaningful difference in the pressure your heart and brain are actually experiencing, even if your arm-cuff reading does not look alarming.

The arterial stiffness finding mentioned earlier connects directly here. When the aorta stiffens, the pressure wave that travels along it bounces back toward the heart faster, arriving during the ejection phase rather than during relaxation. That reflected wave adds to the central pressure the heart encounters. So even if two people have the same peripheral blood pressure reading, the one with stiffer arteries after an energy drink is putting more strain on the heart itself.