Why do we get a second wind when we are tired?
The Backup Fuel Switch
Why do we get a second wind when we are tired?
You're running around at recess, or dancing at a party, or helping your family move furniture all afternoon. Your legs feel like wet noodles. Your arms won't lift. You collapse on the couch thinking, "I'm done. Finished. Cooked." But then — ten minutes later — you pop back up, ready to go again. What just happened?
When you first start moving hard, your muscles burn through their favorite fuel — a sugar called glucose that's stored right inside them, ready to go. It's like having snacks in your backpack. Fast, easy, perfect. But after a while, those snacks run out. Your muscles start complaining. "We're empty! We need a break!" That's when you feel the first wave of tired.
