Aerobic Exercises Versus Resistance Exercises Effect on the Natural Killer Cells in Children

Natural killer cells (NK) are a heterogeneous population of cells that mediate killing of a broad range of target cells; they are highly sensitive to physical exercises. Most studies have been conducted on adults and old with little regard to adolescents and children. This study was conducted to inves-tigate the effect of aerobic exercise versus resistance exercise on NK cells CD3^–/CD 16^+/CD56^+ number in healthy children. Fifty healthy children, from both sexes; age ranged from 7- 12 years old, participated in the study. They were divided into two study groups of equal number. Group I received aerobic exercises on treadmill with 60-75% of maximum heart rate (HR reserve) for 2 successive weeks, 3 sessions/week. Group II received resistance exercises with the same intensity and duration. Blood samples were taken before the 1st session and after the last session of each group. NK cells number was detected by flow cytometry. Both groups showed a statistically significant increase in NK cells number but in favor to group II. It was concluded that resistance exercise showed a greater increase in NK cell number as they cause pronounced muscle damage than aerobic exercises.