Please choose the correct ending to complete the given sentence: Health: [header] How to wake up quickly [title] Let natural light in. [step] Our brains respond to natural light by sending signals to the nervous system to raise body temperature, produce the hormone cortisol and reduce the amount of sleep-inducing melatonin in the bloodstream, all of which are vital to feeling awake. [substeps] Make sure you don't have heavy blinds or curtains blocking natural light from your bedroom.

Ending1: Choose bright light colors that are calming and relaxing, as opposed to light colors that create shadows or softly reflect light. [title] Incorporate sleeping-yoga or meditation into your routine. Ending2: This might make it harder to sleep, for instance, if your curtains block bluish light. Make sure the room isn't at a temperature above 100ºf (38 degrees c). Ending3: Open the curtains and let the light in as soon as you wake up. During the winter months, when the sun rises later, consider getting an alarm clock that uses light to stimulate those important bodily processes. Ending4: Use natural light lamps or plug-in lights in fluorescent, red, yellow, and blue shades that keep the light from streaming through your windows. Set blackout curtains or blinds that close at night.

Answer format: ending1/ending2/ending3/ending4