Longest submergence underwater in a controlled environment

The record for the longest uninterrupted underwater submergence is 4 days and 4 hours (100 hours in total) and was achieved by Ronny Frimann (Norway) to raise funds for the WWF. The official attempt began on 14 June 2007 at 4.55 p.m., after a failed start on the previous day, and ended on 18 June 2007 at 8.55 p.m. in a water tank located at the Central Station, in Oslo, Norway. During the submergence Ronnie wore a diving dry suit and helmet equipped with a catheter and tubes for nutritional fluids and air supply. When he broke the surface of the water, after 100 hours, Ronnie had lost 7.5 kg (16 lb 8 oz).