Understanding the ins and outs of heart rate can help you determine your level of physical fitness and pick up on any problems that may develop.

Bradycardia

Attractive,Blond,Woman,Taking,Her,Pulse

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Tired,African-american,Business,Woman,With,Headache,At,Office,,Feeling,Sick

Anatomy,Of,Human,Heart

Medical,Professional,Measures,The,Pulse,Of,A,Male,Patient's,Wrist

Anemia,Blood,For,Test,,,Medical,Concept,,,Diagnosis,Iron

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Hands,Of,A,Woman,Checking,Her,Pulse,With,Two,Fingers,

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Experienced,Doctor,Holding,Electrocardiogram,Results,Of,A,Young,Man.,Man

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National Institutes of Health

Mayo Clinic

American Heart Association

Merck Manuals

<div class="" data-block="true" data-editor="847gd" data-offset-key="8t9tm-0-0">
<div class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr" data-offset-key="8t9tm-0-0"><span data-offset-key="8t9tm-0-0"><span data-text="true">There are about 1.5 gallons (or 5.5 liters) of blood in the average adult body. Blood regenerates every second. Two million new red blood cells a second, to be exact. We all know that the circulatory system transports oxygen throughout the body. </span></span><span class="hardreadability"><span data-offset-key="8t9tm-1-0"><span data-text="true">But did you know that it also transports electrolytes, carbon dioxide, hormones, and amino acids</span></span></span><span data-offset-key="8t9tm-2-0"><span data-text="true">? </span></span></div>
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<div class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr" data-offset-key="2djib-0-0"><span data-offset-key="2djib-0-0"><span data-text="true">Blood consists of red cells, white cells, platelets, and plasma. The circulatory system closely relates</span></span><span data-offset-key="2djib-2-0"><span data-text="true"> to the lymphatic system. </span></span><span class="hardreadability"><span data-offset-key="2djib-3-0"><span data-text="true">Lymph fluid is plasma that has filtered through the body and returned to the lymphatic system</span></span></span><span data-offset-key="2djib-4-0"><span data-text="true">. </span></span></div>
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<div class="" data-block="true" data-editor="847gd" data-offset-key="71uvp-0-0">
<div class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr" data-offset-key="71uvp-0-0"><span data-offset-key="71uvp-0-0"><span data-text="true">The circulatory system is prone to cardiovascular diseases. For example, stroke, hypertension, and heart failure affect these areas. Healthy eating, exercise, and restricting tobacco and alcohol intake prevent conditions like these. Certain conditions, like high and low blood pressure, are hereditary. It is important to know your family history. Inform your doctor of any history of heart problems.</span></span></div>
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Anatomy

<div class="" data-block="true" data-editor="8v4h4" data-offset-key="1smsj-0-0">
<div class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr" data-offset-key="1smsj-0-0"><span data-offset-key="1smsj-0-0">Anatomy is a branch of biology. This branch of science in particular deals with organisms and their biological structure. Human anatomy, along with physiology and biochemistry, forms the basis of medicine.</span></div>
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<div class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr" data-offset-key="8jihb-0-0"><span data-offset-key="8jihb-0-0">Some parts that make up the body's structure are </span><span class="adverb"><span data-offset-key="8jihb-1-0">incredibly</span></span><span data-offset-key="8jihb-2-0"> complex. Take the circulatory system, for example, which contains the heart and blood vessels. This system </span><span class="complexword"><span data-offset-key="8jihb-3-0">handles a lot of responsibility.</span></span><span data-offset-key="8jihb-4-0"> many crucial functions. It transports blood, nutrients, waste products, immune cells, and clotting cells. It is also </span><span class="adverb"><span data-offset-key="8jihb-5-0">closely</span></span><span data-offset-key="8jihb-6-0"> tied to the lymphatic system and our immune system. </span></div>
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<div class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr" data-offset-key="8jihb-0-0"><span data-offset-key="8jihb-6-0">As you can see, no one part of our anatomy functions completely separate from the others. </span>All the parts of the structure must get along in order for the body to function.</div>
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Circulatory System

All About Heart Rate Changes and What Is Normal

7. How to Check Your Heart Rate

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