Replay Your First Real KissOr listen to the songs you loved when you were 18, driving your first car, the wind whipping through your hair. When asked to recall old times or to listen to nostalgic music, people reported feeling physically warmer than when they were asked to remember ordinary things, found a study published in the journal Emotion. As proof, they could immerse their hands in ice water longer and thought a cold room was a higher temperature than it really was. Psychological warmth activates the same circuits in the brain associated with physical warmth, the theory goes...which effectively convert memories' golden glow into (the perception of) heat.
Take a Vase BreathFirst-time students who took a mere half-hour lesson in g-Tummo, a Tibetan "inner heat" meditation, increased their body temps in just 10 minutes...without moving. Learning the "vase breath"—a technique that involves contracting the abdominal and pelvic muscles while holding hot air in the belly—allowed the students to raise their core body temperature to a sweaty 38.3°C (~101°F), reported researchers at the National University of Singapore. When experienced Tibetan nuns practice g-Tummo, they combine vase breath with a visualization exercise (imagining a fire along their spinal column) and can sustain fever-zone temperatures long enough to dry out damp cloths in below-zero conditions. G-Tummo's potential benefits go far beyond warming up, the study reports; the meditation technique may also improve alertness, memory, reaction time and immunity.
Feed Your Inner FurnaceThe more work it takes to digest something, the more heat your body produces, says Robert Kenefick, PhD, a research physiologist at the Thermal and Mountain Medicine Division of the US Army Research Institute of Environmental Medicine. One mountaineer's trick, he says, is to add slow-to-digest butter: "Hot chocolate with half a stick of butter in it tastes good, generates heat and warms you up when you are freezing in a tent on the side of a mountain." But Kenefick only recommends rich, caloric stuff for when we're outside for long periods of time shivering—not walking from our car to the mall. (Plus, buttery cocoa somehow doesn't taste as great at home.) For tamer situations, he suggests the standard cold-weather fare: hot drinks and soup, which activate thermal (heat-sensing) receptors along the digestive tract. This gives rise to a warming sensation, even if your body temperature doesn't actually increase.
Next: How to get out of your warm bed on a cold morning