What stretching actually does to your body ft. Sofie Dossi

Stretching keeps your muscles flexible, mobile, and strong. By stretching your muscles and the fascia, or connective tissue, that surrounds them, you can relieve tension, reduce body aches, improve your posture, and more.

When your muscles are tight, they can shorten and weaken. For instance, spending all day in a chair may result in hamstring pain in the back of the thigh, making it more difficult to fully extend your leg or straighten your knee. 

Suddenly using tight muscles for a demanding activity can also result in sprains and other muscle injuries. Stretching regularly prevents you from putting too much strain on your muscles and can keep your muscles and joints flexible.

  1. Wakes up your body: Your body detects changes in muscle length and movement while stretching and prepares to become active by increasing blood flow. Increased blood flow throughout the body causes you to feel more awake throughout the day.
  2. Increase blood flow: According to the American Council on Exercise, stretching can boost blood flow to all body areas, including the brain. Healthy blood flow is important, especially in the morning after a full night of sleep. Adequate blood flow improves focus and sharpens the senses.
  3. Improves flexibility: Stretching allows your muscles to move more effectively, improving your range of motion and flexibility and reducing the resistance on your muscles during exercise. Stretching helps restore neural connections between the brain and muscles, improves coordination, and allows you to modify your technique to keep your workout movements flexible.Prevents injuries: Warm-up stretches reduce your risk of injury by prepping the muscles for peak performance before a strenuous workout and reducing the risk of damaging the structures and fibers of your muscles. If you start exercising immediately without warming up, the portions that are still locked or stiff are most vulnerable to injury. Increased blood flow to the muscles can also help lessen soreness after exercise
https://www.medicinenet.com/what_does_stretching_do_for_your_body/article.htm