Evaluation of Blood Lactate and Plasma Insulin During High-intensity Exercise by Antecubital Vein Catheterization

The overall goal of this experiment is to obtain multiple venous blood samples from a single subject during cycle ergometer exercise. This measure can help answer key questions in porous physiology and hormonal and metabolized variation during different exercise modalities. The main advantage of this technique is that multiple blood samples can be obtained, even during exercise.

Demonstrating the procedures will be Rie Oosaki who collaborate with our laboratory. To evaluate blood, hormonal, and metabolite dynamics from the antecubital vein during high intensity interval exercise protocol, have the subject first perform a five-minute warmup on the ergometer at low-intensity. After a five minute rest, have the subject perform three 30 second high-intensity exercise intervals at 90 percent intensity at the power average determined from a previously performed Wingate test, separated by four minutes of rest per exercise interval.

For blood sample collection, tie a tourniquet around the arm selected for the catheterization and identify the antecubital vein. Sterilize the skin with alcohol and insert the tip of a sterilized cannula into the antecubital vein and in an approximately 15 degree angle to the skin. If the cannulation is successful, a backflash of blood should be observed.

After removing the needle, secure the cannula, and place a cotton tissue under the needle. Remove heparin with an empty collection tube and connect a new container for blood collection to the cannula. Aspirate approximately 2.5 ml of blood and close the butterfly, immediately placing the sample on ice.

Then, inject heparin the full length of the tube to avoid blood sample coagulation, and have the subject begin the next series of exercise intervals. After the last sample has been collected, carefully remove the cannulation tube and disinfect the skin with more alcohol. Gently press a piece of sterile cotton onto the collection site to minimize bleeding and transfer 1.5 ml of blood from each sample into individual 1.5 ml microcentrifuge tubes on ice.

Use the lactate detector, measure the blood lactate of each 1 ml blood sample, and centrifuge twice the 1.5 ml blood sample aliquots. Transfer the supernatants into new mirocentrifuge tubes, and centrifuge the samples again in transfer supernatants to new tubes. Then store the purified plasma samples at minus 80 degree Celsius until plasma insulin analysis by ELISA.

In this representative experiment, plasma insulin levels decreased in all six patient peripheral blood samples during the first and third 30 second high intensity interval exercise periods, but increased during the second interval in recovery periods. Plasma lactate, however, decreased during the second and third 30 second high intensity interval exercise periods and increased during the first 30 second interval and recovery periods. While attempting this procedure, it is important to remember to maintain the blood samples at no colder than 40 degrees Celsius.

Following this procedure, other methods like Brodgar's Analysis can be performed to answer additional questions about pH level variations during exercise. After watching this video, you should have a good understanding of how to collect consecutive blood samples from the antecubital vein during cycle ergometer exercise.