The effects of acute exercise on neutrophils and plasma oxidative stress

Purpose: To investigate the influence of intensity versus total energy expenditure on neutrophilia and blood oxidative stress to acute exercise. Methods: Nine males (18-30 yr) completed one maximal (Max) and three submaximal exercise sessions: 1) 45 min at 10% above (LT+) lactate threshold (LT), 2) 45 min at 10% below (LT-) LT, and 3) 10% below LT until caloric expenditure equaled the 10%+ trial (LT-kcal). Blood was sampled before (PRE), immediately (POST), I h, and 2 h after exercise to measure neutrophils, myeloperoxidase, superoxide (O-2-), neutrophil activation (O-2-/neutrophils), ascorbic acid, uric acid, malondialdehyde, and lipid hydroperoxides. Results: Intensity-dependent neutrophilia occurred POST exercise with significant increases (P less than or equal to 0.05) after Max and LT+. A second neutrophilia wave occurred 2 h postexercise. Superoxide was elevated POST (Max) and 2 h post (Max and LT+). In contrast, O-2-/neutrophils was increased at 2 h only (Max and LT+). These data indicate that immediately postexercise, total neutrophil number rather than activation best represents neutrophil-generated reactive species within blood. POST Max, ascorbic acid and uric acid were decreased indicating a blood oxidative stress occurred. Alternately, total energy expenditure was not related to any marker of neutrophilia or oxidative stress. Conclusion: Exercise intensity plays a major role in postexercise blood oxidative stress, whereas total exercise energy expenditure does not. Further, neutrophils recruited into circulation during exercise may impose a threshold dependent oxidative stress in blood plasma after exercise.