title: No effect of seasonal variation in training load on immuno-endocrine responses to acute exhaustive exercise.
abstract: This study was designed to examine the relationship between seasonal changes in training and competition load, and changes in leukocyte subsets, stress hormones, and interleukin-6 (IL-6) in response to a standardised bout of endurance exercise. In addition, changes in mood states were monitored. Ten male, international Nordic skiers, age 20-29, maximal oxygen uptake 70-82 ml x kg(-1) x min(-1) performed the same incremental treadmill tests to exhaustion at the same time of day (+/-1 h), during the competitive season (in-season HI test) and the recovery season (off-season LO test). The subject filled out a training and competition log (TC score) for three weeks prior to each test and a 65-item Profile of Mood State (POMS) test on arrival at the laboratory. Venous blood for haematological, hormonal, and IL-6 analysis was drawn before and at 0, 15, 30, 60, 120 and 240 min after the test. TC score was more than twice as high during the competitive season (16.0 +/- 3.9) compared to the off-season period (7.0 +/- 4.4). An ANOVA procedure for repeated measures showed no difference in exercise induced changes in concentrations of neutrocytes, lymphocytes, epinephrine, ACTH or cortisol between the in-season HI and off-season LO tests; however, norepinephrine and the IL-6 concentrations were elevated at the in-season HI test compared to the off-season LO test. There were no significant differences in POMS global mood score or sub-scores between the in-season HI and the off-season LO tests. Thus, in a group of elite Nordic skiers, we conclude that a doubling of the training and competition load during the winter season does not alter the leukocyte and stress hormone responses to an incremental exercise test to exhaustion.
authors.affiliation: Norwegian National Sports Center, Oslo.
authors.forename: O
authors.initials: O
authors.lastname: Ronsen
authors.forename: K
authors.initials: K
authors.lastname: Holm
authors.forename: H
authors.initials: H
authors.lastname: Staff
authors.forename: P K
authors.initials: PK
authors.lastname: Opstad
authors.forename: B K
authors.initials: BK
authors.lastname: Pedersen
authors.forename: R
authors.initials: R
authors.lastname: Bahr
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000223:Adaptation, Psychological; D000305:Adrenal Cortex Hormones / Q000097:blood; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D004703:Endocrine System / Q000502:physiology*; D015444:Exercise / Q000502:physiology* / Q000523:psychology; D006801:Humans; D007107:Immune System / Q000502:physiology*; D015850:Interleukin-6 / Q000097:blood; D007962:Leukocytes / Q000378:metabolism; D008297:Male; D009504:Neutrophils / Q000378:metabolism; D010806:Physical Education and Training / Q000379:methods*; D012621:Seasons; D012865:Skiing / Q000502:physiology* / Q000523:psychology
chemical_list: D000305:Adrenal Cortex Hormones; D015850:Interleukin-6; D000324:Adrenocorticotropic Hormone