CPR First Aid

What Causes Low Blood Pressure and High Heart Rate

What Causes Low Blood Pressure and High Heart Rate?

It’s typical for people to experience low blood pressure and high heart rate at the same time. This can be triggered by a variety of conditions while in some cases, the cause is unknown. Dehydration, low blood sugar, and anxiety are typical examples causing this phenomenon.

Normally, having low blood pressure and high pulse is short-lived, and simple lifestyle changes are all that are needed to improve the condition. However, depending on the underlying condition, medication or other medical intervention may be necessary for others.

Understanding Blood Pressure

Blood pressure (BP) is the force of your blood pushing against the walls of your arteries. Each time your heart beats, it pumps blood into the arteries. Your blood pressure is highest when your heart beats, pumping the blood. This is called systolic pressure. When your heart relaxes between beats, your blood pressure falls. This is called diastolic pressure.

Your blood pressure reading uses these two numbers. Usually, the systolic number is written above or before the diastolic number. For example, 120/80 (spoken as “120 over 80”) means you have a systolic pressure of 120 and a diastolic pressure of 80.

In many instances, low blood is not a cause for alarm. On the other hand, diseases and treatments are commonly associated with high blood pressure or hypertension.

Low Blood Pressure

Low blood pressure or hypotension, is when the force of your blood against your artery walls is too low. It is usually caused by a medical condition such as dehydration, heart disease, or kidney disease.

A reading below the normal blood pressure range is indicative of hypotension.

  • Those aged 18 and younger, typically < 90/60 mmHg
  • For adults aged 19 to 64, it is < 95/60 mmHg

What is Heart Rate

Heart rate is the number of times your heart beats per minute. A normal heart rate is 60 to 100 beats per minute. If your heart rate is below 60 beats per minute, it’s called bradycardia, and if your heart rate is above 100 beats per minute, it’s called tachycardia.

The Difference Between Heart Rate and Pulse

While these terms are often used interchangeably, they are actually two different things. Your heart rate can be affected by a variety of factors, including exercise, stress, and medications. Your pulse, on the other hand, is determined by your heart rate and the amount of blood your heart is pumping.

High Heart Rate

Tachycardia is when your heart beats too fast. Some factors that can lead the heart to race are as follows.

  • Exercise – the heart needs to pump faster to ensure muscles have enough oxygen
  • Stress
  • Caffeine
  • Nicotine
  • Medications e.g. epinephrine (used to treat allergies), albuterol (used to treat asthma), and thyroxine (used to treat hypothyroidism)
  • Arrhythmias – abnormal heart rhythms
  • Fever
  • Hypovolemic shock – severe blood or fluid loss
  • Anemia – low level of red blood cells
  • Pulmonary embolism – blood clot in the lungs

Causes of Low BP Coupled with High Heart Rate

The following situations may result in the occurrence of both low blood pressure and high heart rate but aren’t necessarily due to any specific disease process.


Not drinking enough fluids can cause low blood pressure, especially if you’re also sweating a lot or have diarrhea.


Low blood pressure is common during pregnancy, starting in the first trimester and continuing throughout. It’s caused by the extra blood in the body and the increased demand for fluids.

Blood loss

Significant blood loss, either internally or externally, can cause low blood pressure. To compensate for the decreased oxygen delivery all throughout the body, heart rate increases to push more oxygenated blood to the organs to prevent them from shutting down.


Some medications can cause low blood pressure, such as diuretics (water pills), ACE inhibitors (used to treat high blood pressure and heart conditions), and certain beta-blockers (used to treat heart conditions and migraines).

Endocrine disorders

Certain endocrine disorders, such as Addison’s disease (a disorder of the adrenal glands) and hypothyroidism (an underactive thyroid), can cause low blood pressure.

Septic shock

This is a serious condition caused by infection affecting immune responses and damaging organ systems. It results in a drop in blood pressure, which can be life-threatening.

Cardiac arrest

This is a medical emergency caused by the heart stopping abruptly. It results in a sudden drop in blood pressure and is often fatal.


This is a severe allergic reaction that can cause low blood pressure, swelling of the airways, and difficulty breathing. It can be life-threatening.

Low blood sugar

This condition, also called hypoglycemia, can cause low blood pressure, dizziness, sweating, and confusion.

Orthostatic hypotension

This condition occurs when blood pressure drops suddenly upon standing up from a sitting or lying down position. It can cause dizziness or lightheadedness.

Is Treatment Needed for Low Blood Pressure and High Heart Rate

Both low BP and high heart rate can cause symptoms such as dizziness, lightheadedness, and fainting. If you experience either condition that persists, it’s important to see your doctor so they can determine the cause and recommend treatment. If you are a caregiver in Adelaide or someone wanting to obtain first aid knowledge and skills to be more prepared in these scenarios, learn more about CPR First Aid’s life-saving first aid courses in Adelaide

Low BP Treatment

In most cases, low blood pressure is not an immediate cause of concern. Oftentimes this occurs when an individual has been in the same (flat) position for too long and makes an abrupt movement to an upright position e.g. from lying or sitting to standing up quickly. Avoid instantaneous movements, slow down and allow the body to rest until your blood pressure goes back to normal.

If an individual is more prone to low blood pressure symptoms, review the different aforementioned causes and for starters, gradually alter lifestyle habits that may trigger this condition. This will include changes in diet and physical activities. Furthermore, always be mindful when taking medicine to lower blood pressure. Once symptoms are experienced more frequently, medication or dosage may need to be adjusted by the doctor.

Racing Heart Treatment

Keep in mind that a high heart rate is not the same as having an irregular heartbeat. Again, the body will have to recover from its stressors. Relaxing the mind and controlling breathing are helpful things to do as an initial response. The body’s goal here is to ensure that oxygen-rich blood reaches the muscles and organs to bring back balance.

For out-of-the-ordinary causes, identify the start of the condition and continue to monitor the situation. Seek medical help right away if symptoms last longer than expected.

In conclusion, although low blood pressure and high heart rate are manageable conditions, it is still important to determine the cause and frequency of symptoms occurring so that if treatment is needed, the doctor can have a better understanding of what’s going on and make a proper diagnosis.

First Aid Management in Adelaide CBD

CPR First Aid in Adelaide is a leading provider of cardiopulmonary resuscitation (CPR) training and first aid courses. We deliver tailored and nationally accredited Express, Regular, and Full courses accompanied by fun and dynamic training to suit everyone’s needs. Reach out to us for more details.

Subscribe now & receive Exclusive DISCOUNTS on your booking!