Already immersion itself can trigger certain physical reactions. This can have an unfavourable effect especially on older divers.
- Fluid shift into the body core
- Constriction of the blood vessels of the skin
- Significant increase of urine excretion
The inevitable consequences of these immersion effects are significant fluid loss. In the elderly, this can have a particularly unfavourable effect, because they often tend to drink less anyway. Especially in summer or in (sub) tropical climates dehydration can quickly occur and cause serious diving accidents. “Thick blood” cannot properly contribute to removal (elimination) of inert gas. These immersion effects are especially risky for the cardiovascular system. The fluid shift into the centre of the body forces the heart to suddenly pump more. If skin circulation is reduced as well, the heart has to work against an even higher resistance.
Possible direct consequences are:
- acute hypertension
- circulatory disorders of the heart
- triggering cardiac arrhythmias
- acute breathlessness
Not only pre-existing heart disease may lead to serious health situations in or underwater but also increased risk of drowning as well as sudden cardiac death exist.