It’s normal for your blood pressure to fluctuate throughout the day in response to how active you are, whether you’ve just eaten a meal, and your state of mind. For example, fear or anxiety can cause a sudden rise in blood pressure as it powers up your sympathetic or “fight or flight” nervous system, the portion that prepares you to run or away or fight. In contrast, when you’re in a very relaxed state, your blood pressure may drop, as during sleep or a meditative state. But what if your blood pressure jumps around a lot from measurement to measurement? Should you be concerned?
Why Your Blood Pressure Fluctuates
Your sympathetic, or “fight or flight,” nervous system and your parasympathetic, or the “rest and relaxation,” control center help maintain your blood pressure. When sympathetic activity predominates, your blood pressure tends to rise while it falls when the parasympathetic system predominates. So, you can expect your blood pressure to fluctuate somewhat throughout the day.
Exercise also affects your blood pressure. After an aerobic workout, it’s not uncommon for blood pressure readings to drop for several hours after a workout. Plus, over time, aerobic exercise can lower your resting blood pressure too. In fact, aerobic exercise, based on a study published in the Annals of Internal Medicine, lowers blood pressure more than other blood-pressure friendly habits such as cutting back on alcohol, restricting sodium, and increasing potassium.
What about resistance exercise? During heavy resistance training, blood pressure can increase quite substantially with some people experiencing a rise in systolic blood pressure as high as 280 mm. Hg. However, this rise is only transient. However, if you have a weakness in the wall of a small artery such as one in the brain, known as an aneurysm, straining to lift a weight, sudden stress, or straining to pass stool could cause enough of a rise in blood pressure to cause the blood vessel to rupture, also known as a hemorrhagic stroke.
You can limit the rise in blood pressure you get when you lift by not holding your breath when you lift and by using lighter weights and more reps if you have high blood pressure. If you experience lightheadedness, headache, chest discomfort, dizziness, or difficulty breathing when you lift weights, see your physician.
You can expect some variability in your blood pressure during exercise and with extreme stress, but what if your blood pressure varies a lot even when you’re not physically active or under stress?
Blood Pressure Variability
Some studies suggest that resting blood pressures that fluctuate a lot may raise the risk of having a heart attack or other cardiovascular event. This applies more to home blood pressure readings since being in a doctor’s office can cause a rise in blood pressure because of the stress of being in a different environment. Of concern is a blood pressure significantly higher in the morning relative to the evening. Studies associate an early morning spike in blood pressure with a higher risk of heart attack and stroke. If you take your morning blood pressure and the reading is 15 mm. Hg higher in the morning than it is in the evening, your risk of stroke or heart attack may be greater.
That’s why it’s important to check your blood pressures at home and if the readings jump around or you have higher readings in the morning, write down the values and show them to your physician. Even if your doctor is already treating you for hypertension, blood pressures that vary a lot increase the likelihood of developing complications of hypertension, including damage to organs such as your eyes and kidneys and strokes and heart attacks. Studies also show that blood pressures that vary a lot may speed up the development of complications of diabetes in people with both. Your physician can adjust your blood pressure medications to reduce blood pressure variability.
Make sure you’re checking your blood pressures correctly at home or you could get misleading readings. Here are some tips:
- Empty your bladder beforehand. A full bladder can raise blood pressure by as much as 15 mm. Hg.
- Don’t talk when taking your blood pressure.
- Sit for 5 minutes before getting the first reading. Avoid wearing tight clothing or placing the cuff over your clothes.
- Sit with both feet flat on the floor—no feet or leg crossing.
- Position your arm at heart level.
- Calibrate your monitor with your physician every visit to make sure it’s giving reliable readings.
- Check your blood pressure at different times of day—morning and evening.
- Use an arm cuff. Wrists cuffs are less accurate.
If you have elevated readings, avoid caffeine, and check your medications. Certain ones, such as decongestants, can elevate your blood pressure while they’re still in your system. Talk to your physician about whether the medications you’re taking can affect your blood pressure.
The Bottom Line
One of the most important risk factors for cardiovascular disease and stroke is high blood pressure. However, having a blood pressure that varies a lot and spikes in the morning may increase your risk of health problems too. So, keep tabs on your blood pressure by checking it at home at different times of the day. Don’t depend only on blood pressure checks at your doctor’s office. An investment in a home blood pressure cuff is one well worth making for your health.
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