Blood pressure measures how much force your blood exerts against artery walls. It’s normal for blood pressure to go up and down over the course of a day, but consistently high blood pressure (hypertension) is a leading risk factor for cardiovascular diseases like stroke and heart failure. Unfortunately, it is estimated that over 45% of adults in the U.S. have high blood pressure.
A range of external factors and behaviors can contribute to high blood pressure both in the short-term and over time. Knowing about the causes of high blood pressure can help guide everyday choices that can better manage blood pressure and improve cardiovascular health.
Temporary vs. Long-Term Blood Pressure Spikes
Blood pressure readings can fluctuate throughout the day. Some things cause temporary spikes that last minutes or hours, and then blood pressure returns to normal. Other issues cause more persistent, longer-term increases in blood pressure.
It is important to remember that things that cause short-term spikes can become more serious problems if they persist over time. This is why many factors influencing blood pressure can be classified as both temporary and long-term concerns.
| Factor | Example | Temporary or Long-Term Concern? |
| Acute pain | Temporary illness, like a UTI | Temporary |
| Chronic pain | Long-term condition, like arthritis | Temporary and long-term |
| Dehydration | – | Temporary |
| Food and Drink | Iron deficiency, fasting, caffeine, or alcohol | Temporary and long-term |
| Straining | Constipation or sleep apnea | Temporary and long-term |
| Nicotine | Smoking or vaping | Temporary and long-term |
| Stress | Generalized anxiety | Temporary and long-term |
| “White coat syndrome” | Stress when in a medical setting | Temporary |
| High cholesterol | – | Potentially long-term |
Can Pain Cause High Blood Pressure?
Pain can cause high blood pressure. In one large study, people with chronic and widespread pain were 75% more likely to have high blood pressure, and people with short-term (acute) pain had a 10% higher risk.
Immediate pain provokes a “fight or flight” response from the body, and part of that response involves both increased heart rate and vasoconstriction in addition to retaining salt and water. When that happens, it increases the volume of blood in the body, raising blood pressure. In addition, research suggests that people with chronic pain are more prone to depression, which can also contribute to higher blood pressure.
Many different conditions can cause both acute and chronic pain with a potential effect on blood pressure. For example, pain from a joint injury or urinary tract infection (UTI) could lead to higher blood pressure.
Does Dehydration Cause High Blood Pressure?
Dehydration can have a direct effect on blood pressure. In fact, dehydration can contribute to both low and high blood pressure.
When the body gets dehydrated, water content goes down across the board, including in the blood. That means that blood volume decreases, which pushes blood pressure down.
However, when blood pressure starts to get too low, the body tries to address the problem by holding in water. Sometimes this system overcorrects, leading to excess water retention and a surge in blood pressure.
For this reason, being consistent about staying hydrated can help prevent blood pressure spikes.
What Foods Cause High Blood Pressure?
Many people know that salt intake affects blood pressure, but that’s not the only dietary factor that can contribute to high blood pressure. Low iron levels, caffeine consumption, alcohol use, and fasting can also impact blood pressure.
Low Iron Diet
A number of studies have linked low iron levels to increased blood pressure. Iron in the blood is essential to carrying oxygen throughout the body. In response to iron deficiency, the heart may start to pump faster to try to deliver more oxygen. This can affect heart health, including causing blood pressure changes and raising the risk of heart failure in cases of prolonged, severe deficiency.
When caused by a lack of iron intake, iron deficiency anemia may be treated by consuming more iron-rich foods and/or taking prescription iron supplements.
Low Potassium Diet
Potassium is a mineral the body needs to function, and is found in foods like bananas, beans, and yogurt. When your diet lacks sufficient potassium, blood pressure can creep up.
Caffeine and Coffee
Consuming caffeine, such as in coffee, can cause a brief rise in blood pressure. For most people, though, drinking a moderate amount of caffeine, even on a daily basis, does not increase the risk of hypertension.
The caffeine in coffee may influence the nervous system or stress levels in the body in a way that causes a small uptick in blood pressure. Evidence suggests that certain people, including those who don’t frequently drink coffee, experience a larger increase in blood pressure from caffeine.
Avoiding high doses of caffeine may help prevent blood pressure spikes, particularly for people who already have hypertension or who are more susceptible to the physical effects of caffeine.
Alcohol
Numerous studies have found a strong link between alcohol and high blood pressure. Alcohol affects the nervous system and the production of different hormones, making it harder for the body to control blood pressure.
Over time, habitual or heavy drinking can also impact heart health and body weight in ways that heighten the risk of hypertension.
Experts recommend avoiding alcohol entirely or limiting alcohol consumption to one serving per day for women or up to two servings per day for men.
Fasting
Fasting can cause variable effects on blood pressure. Some research has found that different types of fasting, including short-term fasting, intermittent fasting, and extended fasting, are associated with reduced blood pressure.
That said, not eating can cause high blood pressure. Fasting may interfere with electrolyte levels, including the amount of potassium in the body. A lack of potassium can throw off heart rate and push up blood pressure.
Ultimately, heart health guidelines suggest focusing on a balanced diet that provides essential vitamins and minerals without being too high in sodium.
Can “Straining” Factors Cause High Blood Pressure?
Certain things that strain the cardiovascular system can increase blood pressure. For instance, difficulty passing stool (constipation) may cause high blood pressure if you strain when trying to have a bowel movement. This straining often includes disrupted breathing that spurs a spike in blood pressure. Exercising, eating plenty of fiber, and taking other steps to prevent constipation may help avoid this uncomfortable straining.
Sleep apnea is another example of how strained breathing can affect blood pressure. Sleep apnea is a condition involving repeated disruptions in breathing that interfere with sleep.
When left untreated, sleep apnea reduces blood oxygen levels during sleep, putting strain on the cardiovascular system. Over time, this means that sleep apnea can be a cause of high blood pressure, making sleep apnea treatment important for overall health.
Does Nicotine Cause High Blood Pressure?
Smoking, vaping, and using other nicotine-containing products can be a cause of high blood pressure. A surge in nicotine activates the sympathetic nervous system, which drives an increase in blood pressure.
Exposure to tobacco smoke also causes damage to the heart and blood vessels. While other products with nicotine, such as vapes and chewing tobacco, avoid smoke exposure, their nicotine content still causes elevations in blood pressure.
Studies have found that nicotine patches have a smaller effect on blood pressure, which is believed to be related to the steady, controlled dose of nicotine that they release. However, they can still have negative effects, which is why they are only intended for use while quitting smoking or other tobacco products.
Can Stress and “White Coat Syndrome” Cause High Blood Pressure?
Stress and anxiety can cause sudden increases in blood pressure because they incite the body’s fight or flight response.
These increases are temporary, so episodes of stress or anxiety aren’t believed to cause long-term hypertension. But chronic stress or anxiety can strain the cardiovascular system, especially if they provoke behaviors that are tied to high blood pressure, like smoking or drinking alcohol.
For many people, the stress of going to the doctor causes their blood pressure readings to be higher at medical appointments. This is known as “white coat syndrome,” and it can make it harder for doctors to identify people with high blood pressure. Taking blood pressure readings at home is one way to help counteract white coat syndrome and get a clearer picture of a person’s blood pressure levels.
Can High Cholesterol Cause High Blood Pressure?
High cholesterol does not directly cause high blood pressure. Cholesterol is a type of fat that the body needs to function properly, but too much cholesterol in the blood can harm the cardiovascular system.
The risk of heart problems is higher in people who have both high cholesterol and high blood pressure. Certain factors, such as smoking, physical inactivity, and obesity, can play a role in the development of both issues.
As with high blood pressure, high cholesterol can be treated, and treatment options include both medications and lifestyle changes.
Reasons Your “Bottom Number” (Diastolic) is High
The bottom number of a blood pressure reading is called the diastolic blood pressure. It measures your blood pressure in-between heart beats. A bottom number over 80 mmHg is considered to be elevated.
The causes of your bottom number of blood pressure to be high overlap significantly with the causes of high blood pressure overall. Things like smoking, eating an unhealthy diet, consuming too much sodium, and not being physically active can heighten both the top and bottom number.
Up to 20% of people with high blood pressure have only high diastolic blood pressure. Research to date is not conclusive but suggests that the main potential causes of having only a higher bottom number include:
- Smoking
- Sleep apnea
- Having a BMI considered overweight or obese
Your Next Steps
Many factors can drive a spike in blood pressure, including things that strain the cardiovascular system or engage the body’s fight or flight response. Often, blood pressure quickly normalizes after a sudden increase, but frequent and long-term blood pressure increases can lead to hypertension and a higher risk of cardiovascular disease.
Practical steps can help keep blood pressure under control. Eating a balanced diet without too much sodium, maintaining a healthy body weight, staying physically active, not smoking, getting quality sleep, and limiting or avoiding alcohol can all help prevent high blood pressure.
Because high blood pressure typically doesn’t cause symptoms, it’s important to take blood pressure readings. If you have high blood pressure, your doctor can suggest the most appropriate treatment, including medications when lifestyle changes alone aren’t enough to keep blood pressure in a normal range.
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Written by
Eric Suni is a health writer and editor with over 15 years of experience. For more than seven years, he worked at Fred Hutch, Seattle's prestigious cancer research center, as a Science Writer and Information Specialist for the National Cancer Institute's Cancer Information Service. His work has been cited in more than 45 published medical journal articles and has been referenced by the CDC, FDA, The New York Times, and numerous state and local health departments.
Reviewed by
Ashley Robinson, PharmD
Ashley Robinson oversees daily operations at TelyRx's Clearwater pharmacy location, optimizes workflow efficiency, and ensures compliance with regulatory standards while maintaining a strong focus on patient safety and quality of care. She collaborates closely with clinical and operations teams to evaluate new medications, support formulary development, and implement process improvements that enhance both patient outcomes and team performance.
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