Exercise-induced changes in blood levels of α-tocopherol

Levels of alpha -tocopherol (alphaT) in plasma and red blood cells (RBC) are assumed to be modulated by exercise. The mechanisms involved remain to be established. We examined the influence of different running bouts on the content of alphaT in RBC (alphaT(RBC)), the concentration in plasma (alphaT plasma), and their relationship with lipolysis, as indicated by changes (Delta) in plasma glycerol concentration ([glycerol]). Eleven healthy runners [mean (SD) age 35 (9) years, height 177.3 (7.6) cm, body mass 69.6 (9.4) kg, and peak oxygen consumption, (V)over dotO(2peak), 57.8 (4.8) ml.kg(-l).min(-1)] performed an incremental treadmill test [duration 17 (2) min, peak velocity, v(peak) 4.8 (0.4) m.s(-1)], a training run [173 (12) min, 57 (4)% v(peak)] and a marathon [197 (24) min, 75 (5)% v(peak)]. Before (pre) and after (post) each run, haematological and lipid parameters, alphaT(RBC) and alphaT(plasma) were determined. Haemoconcentration was observed after each run. Delta [glycerol] was +0.10 (0.10) mmol.l(-1), +0.40 (0.14) mmol.l(-1) and +0.51 (0.15) mmol.l(-1) in the treadmill test, training run and marathon, respectively. When corrected for haemoconcentration, values of alphaT(plasma) decreased [-5.4 (7.5)%, P<0.05] in the treadmill test, were unchanged [+0.7 (8.7)%] in the training run and increased [+7.8 (8.3)%, P<0.05] in the marathon. alphaT(RBC) decreased [pre vs post: 22.7 (3.2) nmol.g haemoglobin(-1) (nmol.g Hb(-1)) vs 18.9 (3.8) nmol.g Hb(-1), P<0.05] in the treadmill test and was not significantly changed in either the training run [20.8 (1.9) nmol-g Hb(-1) vs 19.1 (3.0) nmol.g Hb(-1)] or the marathon [21.6 (2.9) nmol.g Hb(-1) vs 23.4 (2.7) nmol.g Hb(-1)]. <Delta>alpha /T-RBC and Delta alphaT(plasma) were positively related to Delta [glycerol]. The reduction in alphaT(RBC) and alphaT(plasma) after short-lasting heavy exercise indicates the consumption of alphaT, whereas the association between Delta alphaT and Delta [glycerol] suggests mobilisation of alphaT, especially in long-lasting exercises. However, although alphaT appears to be influenced by exercise, the results suggest a well-balanced regulation of alphaT during exercise resulting in small, and only in part, significant Delta alphaT in blood.