It can increase congestion in your sinuses and nasal passages. The solution is to get a humidifier – especially in the bedroom while you sleep. Dr. Neeta Ogdenis anallergist and immunologist – and she says that’ll keep your respiratory tract lubricated. However, other indoor allergens, like mold, can grow like crazy in a moist environment. So you want a happy medium between too dry – and too humid. So set your humidifier below 50%.