Moderate Exercise and Immune Response in Rats: A Model for Cancer Prevention / Exercício Moderado e Resposta Imune em Ratos: Um Modelo para a Prevenção do Câncer

Exercise is believed to cause changes in population and/or activity of immunocompetent cells. Study of this relationship is difficult in humans because of the multifactorial nature of human physiology and concomitant problems in controlling extraneous variables. We have investigated the effects of 4 weeks of moderate exercise training on percentage of NK cells and Lymphocyte activity in Wistar male rats under tightly controlled laboratory conditions. The animals were randomized into two groups: exercise and control. Exercised rats ran at a treadmill speed of 20 m/min (moderate exercise intensity), for 20 minutes, 6 days/week. Laboratory and handling conditions were matched, and food was controlled for both groups. Twenty-four hours after the exercise training program, lymphocyte response did not change significantly (p>0.05). Exercised rats demonstrated a significant increase in the percentage of circulating NK cell population (p