You spend roughly one-third of your life in bed. That fact alone makes your mattress one of the most important investments you can make for your health. Yet most people replace their mattress only when it sags visibly or springs start poking through — long after the damage to their sleep quality has set in. Research consistently shows a direct link between mattress quality, sleep duration, and overall wellbeing. Whether you struggle with back pain , toss and turn all night, or simply wake up feeling unrested, your mattress may be the culprit. In this comprehensive guide, we break down exactly how your mattress affects sleep quality — and what you can do about it. The Science of Sleep and Mattress Support Sleep isn't passive — it's a deeply active biological process that repairs tissue, consolidates memory, and regulates hormones. For this process to unfold properly, your body needs to cycle through four distinct sleep stages: light sleep (N1 and N2), deep sleep (N3/slow-w...