Blood leukocyte and glutamine fluctuations after eccentric exercise

Area of Science:

• Exercise Physiology
• Immunology
• Biochemistry

Background:

• Skeletal muscle produces glutamine, vital for immune cells like lymphocytes and macrophages.
• Exercise-induced muscle damage can impair immune function by causing inflammation and reducing glutamine.
• Creatine kinase (CK) activity serves as an indicator of muscle damage.

Purpose of the Study:

• To investigate the impact of exercise-induced muscle damage on blood leukocyte and glutamine concentrations.
• To compare these changes in individuals with high serum CK activity versus those with low CK activity.

Main Methods:

• Twelve females underwent maximal eccentric resistance exercise.
• Blood samples were collected pre-exercise and up to 9 days post-exercise.
• Leukocyte subsets and glutamine concentrations were analyzed, categorizing subjects into High CK and Low CK groups.

Main Results:

• No significant changes were observed in lymphocyte, monocyte, or granulocyte counts in either group.
• Whole blood glutamine concentration significantly decreased in both High CK and Low CK groups post-exercise.
• Glutamine levels dropped from 437 microM pre-exercise to 332 microM at 3 days post-exercise.

Conclusions:

• Eccentric exercise leads to a decrease in whole blood glutamine levels, irrespective of the degree of muscle damage indicated by CK levels.
• The observed glutamine reduction suggests an impact on muscle metabolism, but it is not exclusively a response to muscle damage.
• Immune cell populations remained stable, indicating that this type of exercise did not significantly burden the immune system in the short term.