The Spruce reached out to Dr. Karena Wu, Board-Certified Clinical Specialist in Orthopedic Physical Therapy for her input on mattresses. Dr. Karena Wu is Fellowship trained in orthopedic manual physical therapy and often discusses sleeping positions and mattress age in her evaluations with patients. The Spruce tested over 50 mattresses and narrowed their pick down to the best king mattresses available for 2023. The story, The 11 Best King Mattresses, Tested and Reviewed discusses the difference in king size mattresses and picks the best types of mattresses. Their top picks include best budget, best firm, best hybrids, best for couples and best pillow tops to name a few. The king size mattress can absolutely improve a person’s sleep for a number of reasons.