CPR is Tired Work, But Best Not Done in Bed
Spoon Feed
CPR performed by laymen benefits from being done on a hard surface rather than on a mattress, though neither group met the AHA recommended depth of 5cm.
Source
Effectiveness of Lay Bystander Hands-Only Cardiopulmonary Resuscitation on a Mattress versus the Floor: A Randomized Cross-Over Trial. Ann Emerg Med. 2023 Feb 23;S0196-0644(23)00026-4. doi: 10.1016/j.annemergmed.2023.01.012. Online ahead of print.