Why our bodies shake when it's cold. Involuntary muscle contractions keep us warm and even fight infections. "Shivering is a way for our bodies to generate heat when we are cold," says Dr. Natasha Bhuyan, a family physician based in Phoenix, Arizona. Breakthroughs, discoveries, and DIY tips sent every weekday. You're walking down a Chicago street on a blustery winter day, when a particularly strong wind almost whips you off of your feet.

Do you need more sleep in fall and winter? Less sunlight, colder weather, and diet changes make us sleepier--and that's OK. Winter mornings make staying under the covers feel impossible to resist. Breakthroughs, discoveries, and DIY tips sent every weekday. It's a crisp, fall day in mid-November, and though your calendar is filled with evening get-togethers and morning runs, you're feeling sluggish.

Arctic warming has'gone into overdrive': NOAA reveals the top of the world is heating up TWICE as fast as the rest of the planet Warming at the top of the world has gone into overdrive, happening twice as fast as the rest of the globe, and extending unnatural heating into fall and winter, according to a new federal report. This map shows temperatures across the Arctic from October 2015-September 2016 compared to the 1981-2010 average. Get ready to'Waymo' a self-driving cab: Google creates new... The'internet of the road': Government proposals call for... The highest wave in history: UN confirms six-storey-high... Stunning new 3D simulation of carbon moving through the... Get ready to'Waymo' a self-driving cab: Google creates new...