Team,
On the same topic, here's some more interesting information on diuretics and dehydration:
Diuretics add to the dehydration that occurs with exercise from sweating, & insensible and respiratory water loss. The diver also has to take into consideration some additional concerns for fluid loss and replacement:
1. SCUBA cylinders have extremely dry air inside. As this air is taken into the lungs and saturated, nearly twice the normal amount of water is lost from the body.
2. Negative pressure breathing causes divers to loose about 350cc/hour from their circulating blood volume, a phenomenon called immersion diuresis and seen also in snorkelers and swimmers.
3. Cold inhibits anti diuretic hormones, causing peripheral vasoconstriction, driving fluid back into the core and stimulating diuresis resulting in losses of plasma volume.
4. The hypercarbia associated with diving decreases anti diuretic hormones, promoting fluid loss from the plasma volume.
5. Diuretics such as coffee, alcohol, tea, and fresh orange juice also contribute to fluid loss, contributing to pre-dive dehydration.
6. Khosla in 1979 found that there is a 4% heodilution in early immersion from ECF shift into the bloodstream, resulting in an increase in central blood volume. This alters stimulation of pressure and volume receptors, leading to further inhibition of ADH and fluid loss.
7. In addition to the above, the state of chronic hypovolemia and hypokalemia caused by oral diuretics are dangerous to divers by decreasing their susceptibility to decompression illness and cardiac arrhythmias respectively.
The importance of entering a dive well hydrated cannot be over stated. Prehydration of divers should include regular ingestion of fluids several hours before, 15 to 20 minutes before and between dives, particularly if multiple dives are to be made each day. The urine should be clear and copious.
Kind regards
Dennis
On the same topic, here's some more interesting information on diuretics and dehydration:
Diuretics add to the dehydration that occurs with exercise from sweating, & insensible and respiratory water loss. The diver also has to take into consideration some additional concerns for fluid loss and replacement:
1. SCUBA cylinders have extremely dry air inside. As this air is taken into the lungs and saturated, nearly twice the normal amount of water is lost from the body.
2. Negative pressure breathing causes divers to loose about 350cc/hour from their circulating blood volume, a phenomenon called immersion diuresis and seen also in snorkelers and swimmers.
3. Cold inhibits anti diuretic hormones, causing peripheral vasoconstriction, driving fluid back into the core and stimulating diuresis resulting in losses of plasma volume.
4. The hypercarbia associated with diving decreases anti diuretic hormones, promoting fluid loss from the plasma volume.
5. Diuretics such as coffee, alcohol, tea, and fresh orange juice also contribute to fluid loss, contributing to pre-dive dehydration.
6. Khosla in 1979 found that there is a 4% heodilution in early immersion from ECF shift into the bloodstream, resulting in an increase in central blood volume. This alters stimulation of pressure and volume receptors, leading to further inhibition of ADH and fluid loss.
7. In addition to the above, the state of chronic hypovolemia and hypokalemia caused by oral diuretics are dangerous to divers by decreasing their susceptibility to decompression illness and cardiac arrhythmias respectively.
The importance of entering a dive well hydrated cannot be over stated. Prehydration of divers should include regular ingestion of fluids several hours before, 15 to 20 minutes before and between dives, particularly if multiple dives are to be made each day. The urine should be clear and copious.
Kind regards
Dennis
