Your fatigue can be a sign of dehydration. Whether you're working out or working a desk job, your body needs water to work well and keep cool. If you're thirsty, you're already dehydrated. Fix: Drink water throughout the day so your urine is light colored.

Why does dehydration cause fatigue?

That's because your body needs to be properly hydrated to feel energized and function optimally. Here's what happens when you're dehydrated: As dehydration sets in, your blood pressure drops, leading to poor circulation and reduced blood flow to your brain. This causes feelings of sleepiness.

Can dehydration cause you to sleep a lot?

Chronic dehydration reduces the presence of amino acids in your body that produce melatonin. Without enough melatonin, you may not get sleepy at night or may feel fatigued during daylight hours, causing exhaustion and excessive daytime sleepiness.