While lack of sleep is one of the biggest reasons why people can feel tired, it’s not the only explanation. Here are five other reasons you may feel tired.

A vast majority of Americans wake up regularly during the night, according to a U.S. News survey. Sleep expert Wendy Troxel ...

REM stages and one REM stage. Ideally, you repeatedly cycle through each stage. Learn how long each stage lasts.

Chronic fatigue syndrome is a complex, under-recognised illness that disproportionately affects women, yet often goes undiagnosed or misdiagnosed.

Sunlight plays a huge role in our energy levels and sleep quality. One study found that those who got enough morning sunlight ...

Light exposure—especially blue light from digital screens—signals your brain that it’s time to wake up by suppressing melatonin production, the hormone that regulates sleep. If you need ...