Lumbar support refers to the mattress's ability to support the natural curve of the lower back without allowing the spine to sink or arch unnaturally. Back sleepers place the most contact pressure on the hips, lower back, and shoulders, so a mattress that provides even weight distribution helps keep these areas properly supported. If you wake up with lower back soreness, your mattress may be too soft, causing the hips to sink, or too firm, leaving a gap between your lower back and the surface. Hybrid mattresses and memory foam models are often recommended because they combine contouring comfort with firm underlying support.