Investigation of the effect of marathon running on leucocyte counts of subjects of different ethnic origins: relevance to the aetiology of ethnic neutropenia

Abstract

Summary. Healthy subjects of African ancestry, including Afro-Caribbeans, have been observed to have lower total white cell counts and neutrophil counts than healthy Caucasian subjects. The cause of this ethnic neutropenia is unclear. We have previously found no evidence that increased margination of neutrophils is responsible. In this study, we have investigated mobilization of neutrophils from the bone marrow granulocyte reserve by endurance exercise. We investigated subjects of different ethnic origins before and after they had competed in a marathon race. Before the race, the neutrophil counts of Africans/Afro-Caribbeans were signi®cantly lower than those of Caucasians (means 2´49 and 3´21´10 9 /l respectively; P 0´043). After the race, the difference was greater, as was the degree of signi®cance (means 10´21 and 12´33 respectively; P 0´017). The percentage increment was almost identical whereas the absolute increment was considerably less, although of marginal statistical signi®cance (increment 7´72 and 9´12´10 9 /l respectively; P 0´10). Similar changes were observed in the monocyte count. Before the race, the difference in the means was of marginal statistical signi®-cance (0´35 and 0´41´10 9 /l respectively; P 0´105), whereas after the race the difference was greater and was highly signi®cant (means 0´75 and 1´05´10 9 /l respectively; P 0´001). These observations support the results of our earlier study, both of which suggested that ethnic neutropenia is likely to result from a diminished bone marrow reserve rather than being consequent on altered distribution of neutrophils within the blood stream.

Respostas hormonais e imunes agudas decorrentes do treinamento de força em bi-set

“…A leucocitose pode aumentar linearmente de acordo com a elevação da intensidade do exercício 31 . Uma maior secreção de catecolaminas pode ocorrer em sessões de treinamento de força que utilizam menores intervalos de recuperação (< 1 minuto), quando comparadas a protocolos que utilizam períodos de recuperação maiores (> 2 minutos) 24,32 .…”

Neutropenia in 6 ethnic groups from the Caribbean and the U.S.

“…These findings are consistent with those of previous studies conducted in British, Caribbean, and African populations. 5,6,8,11 as well as other studies. 9,19,20 An unexpected finding was that although many Dominicans are of partial African ancestry, women from the Dominican Republic had the highest WBC and ANC.…”

“…A study of the response of the WBC to running a marathon, a reflection of the release of neutrophils from bone marrow stores in response to cortisol, demonstrated that runners of African ancestry had a smaller increase in WBC and ANC than white or Asian runners. 11 Hence, the lower WBC and ANC may be due to smaller bone marrow reserves rather than increased peripheral margination of neutrophils. The WBC response to brief intense exercise, which reflects neutrophil demargination in response to catecholamine release, has also been found to be lower in people of African descent than in those of European descent.…”

Influência do exercício físico agudo realizado até a exaustão sobre o número de leucócitos, linfócitos e citocinas circulantes

“…A leucocitose, que se mostrou percentualmente maior no grupo exaustão moderado em comparação com exaustão leve, pode ter sido causada pela intensidade mais elevada do exercício no grupo moderado 8,23 . O aumento no percentual de linfócitos circulantes (linfocitose) resultante de exercício é passageiro e, provavelmente, se deve à liberação dos hormônios do estresse, principalmente a adrenalina 25 , aumentando a liberação de células de seus compartimentos para a circulação sangüínea.…”