What factors determine bottom time during a dive?

Bottom time during a dive refers to the total amount of time a diver spends at a specific depth before beginning their ascent. This crucial factor is primarily determined by how deep the diver goes and the time required for ascending safely back to the surface. While head being underwater might seem relevant, the concept of bottom time is closely linked to the depth of the dive and the time taken to ascend, since these directly impact nitrogen absorption and off-gassing rates critical to prevent decompression sickness.

Understanding that ascent time is a key component of dive planning helps divers monitor their exposure to pressure, ultimately guiding safe diving practices and adherence to tables or dive computers. The deeper the dive, the shorter the allowable bottom time typically is, to accommodate safe ascent procedures. Thus, planning dives with consideration for depth and ascent time ensures divers prioritize safety and adhere to decompression limits effectively.