Sudden Increase in Blood Pressure (BP) 6 Common Reasons

Changes in the blood pressure occur throughout the day. In fact your blood pressure can change several times within a minute and sudden fluctuations largely depends on what you are doing and your state of mind. However, for most people the blood pressure will not rise above nor drop below the normal range. It is important to understand that there is no specific number that can be considered normal for blood pressure. Not even the widely accepted 120/80 mmHg.

Instead your blood pressure fluctuates within a normal range which changes with age. For adults, the uppermost level is known as the systolic pressure. It is the pressure recorded when your heart contracts and normally can vary from 90 to 119 mmHg. Similarly the lowest level known as the diastolic pressure can vary from 60 to 79 mmHg. It is the pressure recorded when your heart relaxes. Therefore the “ideal” blood pressure for adults which is said to be 120/80mmHg is actually the highest normal reading, after which are either have pre-hypertension or hypertension (high blood pressure).

However, there are some occasions where there can be a minor increase for just short periods of time. It can slightly exceed the normal maximum levels but returns to normal soon thereafter. It is for this reason that doctors take blood pressure readings on at least 3 separate occasions to diagnose hypertension. If one reading is high, your doctor will wait about 5 minutes and ask you to relax before checking your BP again.

Why does blood pressure change?

Remember that there are three factors controlling blood pressure at any one time:

  • The force and rate of the heart contraction.
  • The diameter of the blood vessels throughout the body.
  • The volume and even viscosity (“thickness”) of the blood.

It is further influenced by hormones, electrolytes and nerve impulses. The activity of all these factors collectively determine blood pressure. The entire system is complex and the body has to cater for changes to keep your body working optimally. Your blood pressure changes when you sit down, stand up or lie flat. It drops when you sleep soundly. It can fluctuate in hot or cold weather.

Here are 6 common reasons for a sudden increase in blood pressure.

Physical Activity

Running woman

Walking briskly, running up a flight or steps, swimming a few laps and even energetic dancing can cause your blood pressure to rise. When you are physically active the oxygen demand by the body increases. This is evident by breathing faster. Although you do not know it, your heart and blood pressure has to also change accordingly. The heart beats harder and faster in order to shuttle oxygenated blood throughout your system. This will cause a moderate elevation in blood pressure. If you are a fit person, the change will not be very drastic. In fact, your blood pressure should not exceed the normal range unless you have a problem with BP control.


Stress in any form can alter your blood pressure. But it is psychological stress that is often a major cause of raising the blood pressure. When you become anxious, scared or angry, your blood pressure rises almost immediately. It is due to a combination of nerve impulses from the brain to heart and the effects of stress hormones in the circulation. If you find a sudden rise in blood pressure, you should try to calm down and check your blood pressure again once you feel more settled. A few deep breaths, sitting quietly and focusing on pleasant thoughts may be enough to restore your BP to a normal level. Prolonged psychological stress like worrying about money and relationships can cause chronic hypertension but acute stress tends to alter the blood pressure momentarily.


Nicotine is one of the more widely used substances that can raise blood pressure almost immediately. When you smoke, nicotine as well as a number of other chemicals enter your bloodstream where it acts on different organs and reduces the blood oxygen levels. It causes the heart to beat faster and harder and may also cause the blood vessels to narrow. This raises the blood pressure for a short time, anywhere from 20 minutes to an hour or two. Although your BP will eventually return to normal, consuming another cigarette repeats the entire process. In the long run, the body of a smoker produces more red blood cells and contributes to other changes which results in chronic hypertension.



Apart from nicotine, several other substances can also cause a sudden increase in blood pressure. This includes medication, illicit drugs, alcohol and certain herbs.

  • Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, analgesics like acetaminophen, weight loss drugs, certain allergy medication and drugs to keep you alert are probably the more well known and widely used drugs that can have this effect.
  • Cocaine, methamphetamines and many other illicit drugs can also cause an sudden increase in blood pressure sometimes to very dangerous levels.
  • Alcohol may cause a slight drop in blood pressure initially and in small amounts but with continued alcohol consumption there will be a subsequent rise in BP.
  • Herbs like licorice (liquorice) can cause a significant rise in blood pressure almost immediately after being consumed. The extent of the rise in BP depends on the quantity eaten.

Salt Intake

Salt is one of the major contributors to a sudden increase in blood pressure. It is rapidly absorbed in the gut and alters blood pressure within a very short period of time. Contrary to popular belief, it is not table salt that is the biggest problem. Rather processed foods that are commonplace in the modern diet are laden with sodium which raises blood pressure. The effect is more pronounced in people with kidney disorders. Therefore it is important that people suffering with hypertension and kidney diseases stay on a low sodium diet. This includes avoiding processed foods and using very small amounts of table salt, or none at all, in the daily diet.

Cold Weather

cold weather

Generally blood pressure tends to increase in winter and decrease during summer. It is a very slight alteration in BP but can nevertheless be significant in a person with hypertension. Cold causes the blood vessels on the surface of the body to constrict. This means that the heart has to work harder to circulate blood due to the resistance of the narrower vessels. A sudden rise in blood pressure can occur if you walk into a climate controlled environment where the air conditioning is set on high. It can also occur if you step into a walk-in freezer. Older people may also experience sudden changes in blood pressure when the atmospheric pressure changes prior to a sudden weather shift.

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