The cold and dry air that accompanies winter weather can aggravate your sinuses, adding extra irritation on top of seasonal colds. While in the summer we can use sitali, the cooling breath, to reduce body heat, winter weather calls for the opposite approach. Here are three breathing exercises to help you build internal heat. Try them before stepping outside for a brisk winter workout, hitting the slopes, or heading into Surya Namaskar on a chilly morning. You’ll get a jump on the weather, as well as a better awareness of your breath.