Influence of Glycerol Ingestion on the Blood Glycerol Response

Background :

Despite almost 15 years of research on glycerol ingestion and hydration, and another 30 years of research on the clinical applications of glycerol ingestion, there is still confusion over the best method for ingesting glycerol and water to promote a hyper-hydration. This is unfortunate, as most researchers who study glycerol ingestion and body hydration have subjects ingest in excess of 90 g of glycerol and 26 mL/kg of total fluid.  Typically, this regimen results in significant feelings of nausea, as well as symptoms of blurred vision, head ache, and dizziness.

Purpose:

You are to have one of your team ingest distilled water and then a glycerol solution to track changes in serum and urine osmolality and glycerol.  

Experimental Procedure:

The subject will empty their bladder and then ingest 8 ml/kg of distilled water.

Place a catheter in an antecubital vein.  Keep patent with a 1 mL flush of sterile saline every 10 min.

Once cathetered draw a baseline blood sample at 25 min after water ingestion is complete.

At 30 min post-ingestion, have the subject drink 0.75 g glycerol/kg body weight (make sure you measure and record this added volume) followed by 16 mL/kg distilled water.

Complete symptom sheets for the first hour (min 30, 45, 60, 75 and 90).

At 45, 60, 75, 90, 120 and 150 min, draw a blood sample and have the subject empty his/her bladder.

Process blood samples to get serum samples for subsequent glycerol and osmolality analyses.

Measure and record all urine volumes, and store a 2 mL sample for osmolality analysis.

Repeat all of the above on a separate day.  Instead of the glycerol ingestion, have the subject ingest the added volume as distilled water.

 Data Analyses :

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