Sleep happens in cycles that include three non-rapid eye movement (NREM) stages and one rapid eye movement (REM) stage, repeated 4 to 5 times nightly. Each cycle typically lasts 90 to 110 minutes. The ...

The human eye does not actually see purple, as purple is not a color on the visual spectrum. Purple is a combination of wavelengths from opposite extremes of the spectrum, which technically deosn’t ...

Light sleep is the beginning of your sleep cycle and your body's way of winding down. Breathing, heart rate and muscle changes prepare your body for the deeper sleep to come. Light sleep is broken ...

Deep vein thrombosis (DVT), which is a blood clot that develops in a deep vein, can cause pain, warmth, swelling, or redness (often in your calf muscle) that doesn’t go away. A DVT can be hard to ...

Lean, also called purple drank or sizzurp, mixes codeine-promethazine cough syrup with soda and sometimes hard candy or alcohol. It can create euphoria and heavy sedation. High doses can cause ...