🫀 Rate of Heartbeat & ECG 💓 Rate of Heartbeat

📌 What is heart rate?

The heart rate means how many times your heart beats in one minute.

• In a normal adult, the heart beats around 70 times per minute.
• That means it beats more than 100,000 times in one day without stopping!

💡 Real-life example: Imagine a water pump that supplies water to every tap in a building. The heart works just like that pump—it keeps pumping blood to every part of your body non-stop.

🩸 How much blood does it pump?

• Your body has about 5 liters of blood.
• In one minute, your heart can pump all 5 liters once.
• So in one hour, it can pump 300 liters of blood!

🧠 Who Controls the Speed of the Heartbeat?

The speed or rate of your heartbeat is not random. It is controlled by two main systems:

1. Pacemaker and AV Node (Internal Control)

• The pacemaker (SA Node) and the AV Node are parts of your heart’s own electrical system.
• They automatically control how fast your heart should beat depending on your body’s needs.

2. Brain (External Control)

The brain also sends signals to control the heartbeat when needed.

⬆️ When does the brain increase heart rate?

• During fever, exercise, anger, fright, or stress.
• These situations demand more oxygen, so the brain tells the heart to beat faster.

💡 Example: When you run, your muscles need more oxygen. The brain increases your heart rate to send more oxygen-rich blood.

⬇️ When does the brain slow down heart rate?

• When you’re sleeping, resting, or feeling calm.
• The body needs less energy, so the brain tells the heart to slow down.

💡 Example: During sleep, your heart beats slower, like a machine running in “power-saving mode.”

🧪 ECG (Electrocardiogram)

📌 What is ECG?

An ECG is a test that records the electrical signals your heart produces during each heartbeat.

• Full form: Electrocardiogram
• It shows a graph or wave pattern on paper or a screen.
• This pattern helps doctors see if your heart is beating normally or if there is a problem.

⚡ How is electricity generated in the heart?

Every time the SA node starts a heartbeat, it creates a tiny electrical current.

• This current spreads through the heart and then to the skin.
• Electrodes (sticky patches) are placed on the skin to catch these signals.
• The machine (electrocardiograph) records them as waves.

💡 Real-life example: It’s like a microphone picking up sound from your voice and converting it into waves on a computer.