This is going to depend. I am 32, 300 pounds, with mild back issues. I slept on a foam crib mattress for 5 months and was pretty comfortable. If you are lighter, healthy, and going to be getting lots of moving and stretching I think you will be okay. This is what I used just so you free a reference point. Graco Premium Foam Crib and Toddler Bed Mattress https://www.amazon.com/dp/B010S7VZI0/ref=cm_sw_r_cp_apa_51QRAb5W902F0