What is an effect of extreme dehydration on diving?

Extreme dehydration can have several adverse effects on a diver's physiology and ultimately increase the risk of decompression sickness (DCS). When the body is dehydrated, the blood volume decreases, leading to thicker blood, which can impair circulation and oxygen delivery to cells. Additionally, dehydration can cause an electrolyte imbalance, which further impacts bodily functions.

During a dive, when a diver ascends, any decrease in blood volume and the reduced ability of the body to eliminate nitrogen may lead to the formation of nitrogen bubbles in the tissues and bloodstream. This bubble formation is what causes DCS. Therefore, being dehydrated increases the likelihood of DCS occurring following a dive due to these physiological changes, highlighting the critical importance of maintaining proper hydration levels before and during diving activities.