A bariatric mattress is specifically designed for heavier sleepers with medical needs. These mattresses tend to be firmer and more supportive than their competitors. Most bariatric mattresses support between 600 and 1,000 pounds. Some medical equipment distributors require a prescription for bariatric mattresses, while select retailers sell them over the counter. If your doctor prescribes a bariatric mattress, insurance may cover some or all of the cost.