Experiencing a rapid heartbeat paired with low blood pressure can be unsettling and often signals that something isn't quite right within the body. This condition, where tachycardia meets hypotension, indicates the body's struggle to maintain sufficient blood flow and oxygen delivery to vital organs. To better understand the causes and implications of this condition, we spoke to Dr Bimal Chhajer, Former Consultant, AIIMS and Director, SAAOL Heart Centre, New Delhi, who shared insights on the same.
For many healthy adults, normal blood pressure is below 120/80 millimetres of mercury (mm Hg). While there is no exact threshold for low blood pressure, the National Heart, Lung, and Blood Institute (NHLBI) defines it as anything below 90/60 mm Hg. On the other hand, a high pulse or heart rate is considered to be over 100 beats per minute.
What Causes High Pulse And Low Blood Pressure?
Dehydration
Dehydration takes place when the body’s fluid loss exceeds its intake. This can happen due to excessive sweating, vomiting, diarrhoea, or insufficient fluid intake. “When dehydration sets in, the blood volume decreases, leading to low blood pressure. To compensate for this reduced volume, the heart pumps faster, resulting in a high pulse rate,” explained Dr Chhajer.
Also Read: Dehydration's Impact On Blood Pressure: Expert Explains The Mechanisms And Implications
Heart Conditions
Various heart conditions can lead to a high pulse rate and low blood pressure. Dr Chhajer said, “Arrhythmias, such as atrial fibrillation, cause irregular heartbeats that can disrupt the heart's ability to pump blood efficiently. Heart valve disorders, which affect the flow of blood through the heart, and myocarditis, an inflammation of the heart muscle, can also compromise heart function.” These conditions force the heart to beat faster to maintain adequate circulation, often resulting in hypotension.
Shock
“Shock is a severe condition where there isn't enough blood flow to meet the body's needs. This can occur due to severe infections (septic shock), heart failure (cardiogenic shock), or sudden loss of blood (hypovolemic shock). In shock, the heart tries to compensate by increasing its rate to maintain blood flow,” added Dr Chhajer.
Endocrine Disorders
The endocrine system plays a critical role in regulating heart function and blood pressure. Disorders, such as adrenal insufficiency (Addison's disease) or thyroid dysfunction (thyroid storm) can lead to low blood pressure and a rapid heart rate due to hormonal imbalances affecting heart function and blood vessel tone.
Also Read: Low Blood Volume Could Cause Low Blood Pressure: Immediate Steps To Take
Anaphylaxis
Dr Chhajer said, “Anaphylaxis is a severe and sudden allergic reaction that can develop within minutes of allergen exposure. It causes a sudden drop in blood pressure due to widespread vasodilation (widening of blood vessels) and increased permeability of blood vessels, leading to fluid leakage. The heart responds with a rapid pulse rate to maintain blood flow to vital organs.”
Blood Loss
Significant bleeding, whether from trauma, surgery, or gastrointestinal ulcers, can quickly reduce blood volume. This drop in blood volume results in low blood pressure and triggers an increase in heart rate to maintain circulation.
Medication Side Effects
Certain medications, particularly those used to treat high blood pressure or heart conditions, can cause a compensatory increase in heart rate while lowering blood pressure. Beta-blockers, for example, reduce the heart rate but can sometimes lower blood pressure too much.
Message From The Expert
Dr Chajjer concluded, “In all cases, experiencing a high pulse rate and low blood pressure requires medical evaluation to determine the underlying cause. Diagnostic tests, including blood tests, Electrocardiogram (ECG/EKG), echocardiogram, and monitoring of vital signs, help in identifying the specific condition and guiding appropriate treatment. Immediate medical attention is crucial for severe symptoms or when associated with signs of shock, chest pain, or altered consciousness.”
[Disclaimer: This article contains information provided by an expert and is for informational purposes only. Hence, we advise you to consult your own professional if you are dealing with any health issues to avoid complications.]