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MedlinePlus is a service of the National Library of Medicine (NLM), the world's largest medical library, which is part of the National Institutes of Health (NIH). It was built as an online health information resource for patients and their families and friends.

MedlinePlus presents high-quality, easy to understand, relevant health and wellness information that is trusted.

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MedlinePlus at a Glance

  • Offers information on health topics, human genetics, medical tests, medications, dietary supplements, and healthy recipes.
  • Sourced from more than 1,600 selected organizations.
  • Provides 40,000 links to authoritative health information in English and 18,000 links to information in Spanish.
  • In 2018, 277 million users viewed MedlinePlus more than 700 million times.

Vital Signs

Your vital signs show how well your body is functioning. They are usually measured at doctor's offices, often as part of a health checkup, or during an emergency room visit. They include:

  • Blood pressure, which measures the force of your blood pushing against the walls of your arteries. Blood pressure that is too high or too low can cause problems. Your blood pressure has two numbers. The first number is the pressure when your heart beats and is pumping the blood. The second is from when your heart is at rest, between beats. A normal blood pressure reading for adults is lower than 120/80 and higher than 90/60.
  • Heart rate, or pulse, which measures how fast your heart is beating. A problem with your heart rate may be an arrhythmia. Your normal heart rate depends on factors such as your age, how much you exercise, whether you are sitting or standing, which medicines you take, and your weight.
  • Respiratory rate, which measures your breathing. Mild breathing changes can be from causes such as a stuffy nose or hard exercise. But slow or fast breathing can also be a sign of a serious breathing problem.
  • Temperature, which measures how hot your body is. A body temperature that is higher than normal (over 98.6 °F, or 37 °C) is called a fever.