Why Do We Feel Tired?

How Does Our Brain Tell Us To Sleep?


By: Nathan Britton, Journalist

Whether it’s after a nap or right before bed, we all feel tired. But today’s question is: why do we feel tired?

Part of the reason is because of Circadian Rhythm. Circadian Rhythms are basically when you see light, your brain thinks you should be awake, but when you see darkness it thinks you should be asleep.¬† Also, throughout the day adenosine is made and builds up, which triggers sleep control neurons. During the night, your brain’s Circadian Rhythm tells your pineal gland to produce melatonin.

But why do we feel tired after exercising? As muscles contract, ATP, calcium ions, sodium ions, and potassium ions are used up. The more contractions you do without resting, the more calcium, sodium, and potassium ions drift away. Even though you may have used up all the ions in one muscle, there are enough ions in other muscles to give away. This is why you can exercise more after a break.




Why do we get tired?