Hematocrit change in tropical scuba divers

Area of Science:

• Physiology
• Diving Medicine

Background:

• Dehydration evidence from scuba diving is limited.
• Hematocrit (Ht) is a common indicator of dehydration.
• This study investigated Ht changes during tropical scuba dives.

Purpose of the Study:

• To determine if hematocrit increases after scuba diving in tropical conditions.
• To assess the correlation between dive pressure exposure and hematocrit increase.

Main Methods:

• 21 male and 20 female divers participated in tropical conditions (30°C).
• Venous blood samples were collected before and after a single dive.
• Hematocrit levels were measured using microcapillary centrifugation and visual plate reading.

Main Results:

• A statistically significant increase in hematocrit was observed post-dive (P < .001).
• The mean relative Ht increase was 1.78%.
• A weak but significant correlation was found between dive depth and Ht increase (P = .049).

Conclusions:

• A small, statistically significant increase in hematocrit occurs after warm-water scuba dives.
• The observed Ht changes are minimal and within measurement error.
• Current fluid resuscitation protocols for recreational divers do not require amendment.