Purpose of Blood in Exercise

• Blood's main role during exercise is transport – think of it like Uber for our body's cells! It carries gases, nutrients, waste, hormones, and even helps regulate temperature.

Total Blood Volume

• A 70kg guy has about 5 litres of blood. Imagine 5 one-litre soda bottles filled with blood, but don't visualize that for too long – it's kind of gross!

Blood Composition

• Plasma (55%): The liquid part. Think of it as the 'water' in which all the other components float.

• Blood Cells and Platelets (45%): This includes white blood cells, red blood cells, and platelets.

  • Fun Fact: Ever cut yourself and had a scab form? Thank the platelets for helping repair the injury! 🩹

Types of Blood Cells and their Roles

• White Blood Cells (leucocytes): Less than 1% of blood volume. They're the body's defense squad, fighting off infections.

• Red Blood Cells (erythrocytes): Make up 40-45% of the blood. Think of them as oxygen delivery guys. The percentage of blood that they make up is called the hematocrit.

  • Real-world example: Have you noticed that some people can run longer than others without getting tired? Their hematocrit value might be influenced by training and gender.

When we work out, carbon dioxide increases in our muscles. Our blood helps transport this CO2 from the muscles to our lungs, where we breathe it out.

Oxygen from the lungs gets attached to a substance in our blood called hemoglobin. Think of hemoglobin as an oxygen magnet!

• Fun Fact: In areas of our body where oxygen is needed, like our active muscles, oxygen detaches from the hemoglobin and enters those tissues. It's like a relay race, but for oxygen!

By increasing the amount of hemoglobin in our blood, we can transport more oxygen, improving aerobic performance.

• Training Hack: This is why some athletes train at high altitudes - less oxygen in the air there makes the body produce more hemoglobin. When they come back to sea level, they're super oxygen-efficient!

Warning ⚠️: Some people cheat using blood doping or injecting synthetic EPO to artificially increase their hemoglobin levels. This gives them an unfair advantage in competitions, and it's illegal.