The hematocrit paradox--how does blood doping really work?

The wide-spread assumption that doping with erythropoietin or blood transfusion is only effective by increasing arterial blood O2 content because of rising hematocrit is not self-evident. "Natural blood dopers" (horses, dogs) increase both hematocrit and circulating blood volume during exercise by releasing stored erythrocytes from the spleen. Improvement of aerobic performance by augmenting hemoglobin concentration may be expected until the optimal hematocrit is reached; above this value maximal cardiac output declines due to the steep increase of blood viscosity. Therefore an enlarged blood oxygen content might only be useful if the normal hematocrit of man during exercise is suboptimal. However, recent studies suggest that cardiac power rises after erythropoietin allowing an unchanged cardiac output in spite of increased viscosity. Other factors underlying improved performance after blood doping might be: augmented diffusion capacity for oxygen in lungs and tissues, increased percentage of young red cells with good functional properties (after erythropoietin), increased buffer capacity, increase of blood volume, vasoconstriction, reduced damage by radicals, mood improvement by cerebral effects of erythropoietin. Also the importance of placebo is unknown since double-blind studies are rare. It is suggested that blood doping has multifactorial effects not restricted to the increase in arterial oxygen content.

Extracellular pH defense against lactic acid in untrained and trained altitude residents.

The assumption that buffering at altitude is deteriorated by bicarbonate (bi) reduction was investigated. Extracellular pH defense against lactic acidosis was estimated from changes (Delta) in lactic acid ([La]), [HCO3-], pH and PCO2 in plasma, which equilibrates with interstitial fluid. These quantities were measured in earlobe blood during and after incremental bicycle exercise in 10 untrained (UT) and 11 endurance-trained (TR) highlanders (2,600 m). During exercise the capacity of non-bicarbonate buffers (betanbi=-Delta[La]. DeltapH(-1)-Delta[HCO3-]. DeltapH(-1)) amounted to 40+/-2 (SEM) and 28+/-2 mmol l(-1) in UT and TR, respectively (P<0.01). During recovery beta (nbi) decreased to 20 (UT) and 16 (TR) mmol l(-1) (P<0.001) corresponding to values expected from hemoglobin, dissolved protein and phosphate concentrations related to extracellular fluid (ecf). This was accompanied by a larger decrease of base excess after than during exercise for a given Delta[La]. betabi amounted to 37-41 mmol l(-1) being lower than at sea level. The large exercise betanbi was mainly caused by increasing concentrations of buffers due to temporary shrinking of ecf. Tr has lower betanbi in spite of an increased Hb mass mainly because of an expanded ecf compared to UT. In highlanders betanbi is higher than in lowlanders because of larger Hb mass and reduced ecf and counteracts the decrease in [HCO3-]. The amount of bicarbonate is probably reduced by reduction of the ecf at altitude but this is compensated by lower maximal [La] and more effective hyperventilation resulting in attenuated exercise acidosis at exhaustion.

Endurance exercise and the production of growth hormone and haematopoietic factors in patients with anaemia.

BACKGROUND: Physical activity has been shown to stimulate haematopoiesis in patients with anaemia due to chronic renal failure or haematological malignancies. OBJECTIVE: To evaluate the effect of moderate exercise on the production of haematopoietically active factors. METHODS: Ten patients (four men and six women, mean (SD) age 51 (10) years) with a haemoglobin concentration under 130 g/l (men) or 120 g/l (women) carried out five three minute exercise bouts at an intensity of 80% of the maximal heart rate, corresponding to a lactate concentration of 3 (0.5) mmol/l. Patients rested for three minutes between bouts. The concentrations of interleukin 6, stem cell factor, granulocyte-monocyte colony stimulating factor, granulocyte colony stimulating factor, erythropoietin, and growth hormone (GH) were evaluated before and in the eight hours after exercise. RESULTS: GH had risen significantly 15 minutes after exercise (1.1 (1.3) v 2.7 (2.8) ng/ml; p<0.05). No change in the concentration of the other cytokines and growth factors was observed in the eight hours after exercise. CONCLUSIONS: In patients with anaemia, submaximal exercise does not affect the concentration of haematopoietically active cytokines. However, it leads to an increased concentration of GH. This may be responsible for the improved haematopoiesis observed after an exercise programme in patients with chronic diseases.

Hemoglobin mass and peak oxygen uptake in untrained and trained female altitude residents.

Total hemoglobin mass has not been systematically investigated in females at altitude. We measured this quantity (CO-rebreathing method) as well as peak oxygen uptake in 54 young women (age 22.5 +/- 0.6 SE years) with differing physical fitness living in Bogota (2600 m) and compared the results with those of 19 subjects from 964 m in Colombia and 75 subjects from 35 m in Germany. In spite of an increased hemoglobin concentration the hemoglobin mass was not changed in highlanders (means 9.0 to 9.5 g . kg (-1) in untrained subjects at all altitude levels). Endurance trained athletes, however, showed a rise in hemoglobin mass by 2 - 3 g . kg (-1) at all sites. Erythropoietin was little increased in Bogota; iron stores were within the normal range. Aerobic performance capacity was lower at high altitude than at sea level and remained so also after correction for the hypoxic deterioration in untrained and moderately trained subjects but not in athletes; possibly the cause was reduced daily physical activity in non-athletic Bogotanians compared to lowlanders. After exclusion of the factor V.O(2peak) by analysis of covariance a mean rise of 6.6 % in hemoglobin mass at 2600 m was calculated being smaller than in males (> 12 %). The attenuated increase of hemoglobin mass in female highlanders possibly results from stimulation of ventilation improving arterial oxygen saturation or from an increased hypoxia tolerance of cellular metabolism both caused by female sexual hormones.

Physical performance, depression, immune status and fatigue in patients with hematological malignancies after treatment.

BACKGROUND: Fatigue is a frequent and severe problem after treatment of patients with hematological malignancies. This symptom has been associated with anemia, reduced physical performance, mood, endocrine disorders and impaired nutritional status. Recently, it has been suggested that fatigue can be related to a persistent activation of the immune system with increased production of proinflammatory cytokines. However, there is no conclusive evidence regarding the role of the immune system in the origin of fatigue in cancer patients. PATIENTS AND METHODS: We evaluated the correlation of fatigue with thyroid function, markers of immune activity [interleukin (IL)-1alpha, IL-1 soluble receptor, IL-6, C-reactive protein and neopterin], liver and kidney function, mood and physical ability in 71 patients with hematological malignancies. All patients had been free of relapse and not received treatment (chemotherapy, radiotherapy or immune modulators) for at least 3 months. RESULTS: Fatigue was related to depression (r=0.84; P<0.0001) and reduced performance status (r=-0.61; P<0.0001). However, there was no correlation between fatigue and thyroid, liver and kidney function, anemia, albumin concentration or markers of immune activity (all r-values <0.20; P>0.05). CONCLUSIONS: We conclude that fatigue in relapse-free patients with hematological malignancies is associated with depressive mood and reduced physical performance, but not with impairment of thyroid function, anemia or persistent activation of the immune system.

Erythropoiesis and performance after two weeks of living high and training low in well trained triathletes.

The purpose of our study was to evaluate hematologic acclimatization during 2 weeks of intensive normoxic training with regeneration at moderate altitude (living high-training low, LHTL) and its effects on sea-level performance in well trained athletes compared to another group of equally trained athletes under control conditions (living low - training low, CONTROL). Twenty-one triathletes were ascribed either to LHTL (n = 11; age: 23.0 +/- 4.3 yrs; VO 2 max: 62.5 +/- 9.7 [ml x min -1 x kg -1]) living at 1956 m of altitude or to CONTROL (n = 10; age: 18.7 +/- 5.6 yrs; VO 2 max: 60.5 +/- 6.7 ml x min -1 x kg -1) living at 800 m. Both groups performed an equal training schedule at 800 m. VO 2 max, endurance performance, erythropoietin in serum, hemoglobin mass (Hb tot, CO-rebreathing method) and hematological quantities were measured. A tendency to improved performance in LHTL after the camp was not significant (p < 0.07). Erythropoietin concentration increased temporarily in LHTL (Delta 14.3 +/- 8.7 mU x ml -1; p < 0.012). Hb tot remained unchanged in LHTL whereas was slightly decreased from 12.5 +/- 1.3 to 11.9 +/- 1.3g x kg -1 in CONTROL (p < 0.01). As the reticulocyte number tended to higher values in LHTL than in CONTROL, it seems that a moderate stimulation of erythropoiesis during regeneration at altitude served as a compensation for an exercise-induced destruction of red cells.

Markers of coagulation, fibrinolysis and angiogenesis after strenuous short-term exercise (Wingate-test) in male subjects of varying fitness levels.

It was the aim of the study to analyse the haemostatic system during a high standardized intensive short-term (30 s) exercise (anaerobic Wingate test). Blood samples were taken from 15 male subjects before (t0 ), and within 2 (t1 ), 9 (t2 ) and 30 min (t3 ) after the test. We found that the partial thromboplastin time was markedly shortened, whereas the prothrombin time increased slightly from t0 to t1 (p < 0.002) and remained elevated (t3, p < 0.046). Factor VIII increased from t0 to t1 (p < 0.001) and remained elevated as well (t3, p < 0.001). Fibrin monomers were approximately 15 times higher immediately post-exercise (t1, p < 0.001) and continued to be elevated (t3, p < 0.004). The tissue plasminogen activator increased by 4 times after exercise (t1, p < 0.001) and remained elevated (t3, p < 0.002). The d-dimers increased from t0 to t1 (p < 0.001) as well and remained elevated (t3, p < 0.005). Thrombopoietin concentrations were unchanged, whereas the vascular endothelial growth factor increased immediately post-exercise (t0 to t1, p < 0.011 resp. at t2 p < 0.019) and returned to the control level at t3 (p < 0.878). In conclusion, it was found that prothrombotic markers and, even more pronounced, those of the fibrinolytic system were increased. The study provides evidence that due to intensive short-term exercise the balance of the haemostatic system is shifted to a higher equilibrium. Theoretically, the data show that in the case of a subject with risk factors such as impaired fibrinolysis, unfavourable conditions cannot be excluded.

Hemoglobin mass and peak oxygen uptake in untrained and trained residents of moderate altitude.

Blood composition, hemoglobin mass (CO rebreathing method) and VO2peak were measured in 15 untrained (UT-Bogotá) and 14 trained males (TR-Bogotá) living at 2600 m of altitude, and in 14 untrained lowlanders (UT-Berlin). [Hb] amounted to 15.3 + 0.2(SE) g/dl in UT-Berlin, 17.4 + 0.2 g/dl in UT-Bogotá and 16.0 + 0.2 g/dl in TR-Bogotá. Hb mass was significantly higher in UT-Bogotá (13.2 + 0.4 g/kg, P < 0.01) and in TR-Bogotá (14.7 + 0.5 g/kg, P < 0.001) than in UT-Berlin (11.7 + 0.2 g/kg). In TR-Bogotá also plasma volume was expanded. Erythropoietin concentrations in UT-Bogotá and TR-Bogotá were not significantly increased. There was a positive correlation between blood volume and VO2peak for the pooled values of all subjects, if the oxygen uptake of UT-Berlin was corrected for an ascent to 2600 m. For the Hb mass - VO2peak relation two groups are indicated pointing to two types of altitude acclimatization with different Hb mass increases but similar distribution of aerobic performance capacity. We suggest that different genetic properties in a population of mixed ethnic origin might play a role.

Exercise-induced changes in blood levels of alpha-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 (alphaTplasma), 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, VO2peak, 57.8 (4.8) ml.kg(-1).min(-1)] performed an incremental treadmill test [duration 17 (2) min, peak velocity, vpeak 4.8 (0.4) m.s(-1)], a training run [173 (12) min, 57 (4)% vpeak] and a marathon [197 (24) min, 75 (5)% vpeak]. Before (pre) and after (post) each run, haematological and lipid parameters, alphaT(RBC) and alphaTplasma 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 alphaTplasma 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) nmolg 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)]. deltaalphaT(RBC) and deltaalphaTplasma were positively related to delta[glycerol]. The reduction in alphaTRBC and alphaTplasma after short-lasting heavy exercise indicates the consumption of alphaT, whereas the association between deltaalphaT 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 deltaalphaT in blood.

Extracellular pH defense against lactic acid in normoxia and hypoxia before and after a Himalayan expedition.

The extracellular pH defense against the lactic acidosis resulting from exercise can be estimated from the ratios -delta[La].delta pH-1 (where delta[La] is change in lactic acid concentration and delta pH is change in pH) and delta[HCO3-].delta pH-1 (where delta[HCO3-] is change in bicarbonate concentration) in blood plasma. The difference between -delta[La].delta pH-1 and delta[HCO3-].delta pH-1 yields the capacity of available non-bicarbonate buffers (mainly hemoglobin). In turn, delta[HCO3-].delta pH-1 can be separated into a pure bicarbonate buffering (as calculated at constant carbon dioxide tension) and a hyperventilation effect. These quantities were measured in 12 mountaineers during incremental exercise tests before, and 7-8 days (group 1) or 11-12 days (group 2) after their return from a Himalayan expedition (2800-7600 m altitude) under conditions of normoxia and acute hypoxia. In normoxia -delta[La].delta pH-1 amounted to [mean (SEM)] 92 (6) mmol.l-1 before altitude, of which 19 (4), 48 (1) and 25 (3) mmol.l-1 were due to hyperventilation, bicarbonate and non-bicarbonate buffering, respectively. After altitude -delta[La].delta pH-1 was increased to 128 (12) mmol.l-1 (P < 0.01) in group 1 and decreased to 72 (5) mmol.l-1 in group 2 (P < 0.05), resulting mainly from apparent large changes of non-bicarbonate buffer capacity, which amounted to 49 (14) mmol.l-1 in group 1 and to 10 (2) mmol.l-1 in group 2. In acute hypoxia the apparent increase in non-bicarbonate buffers of group 1 was even larger [140 (18) mmol.l-1]. Since the hemoglobin mass was only modestly elevated after descent, other factors must play a role. It is proposed here that the transport of La- and H+ across cell membranes is differently influenced by high-altitude acclimatization.

Measured fraction of carboxyhaemoglobin depends on oxygen saturation of haemoglobin.

The use of the OSM3 oximeter for measurement of the fraction of carboxyhaemoglobin (FCOHb) in blood allows for estimation of total circulating haemoglobin mass (Hb(tot)) by using the carbon monoxide rebreathing method. To ensure high accuracy of Hb(tot) estimation, potential sources of analytical errors should be identified and adjusted for. Based on observed differences in results of measured FCOHb between simultaneously sampled, arterialized and venous blood samples we investigated the influence of haemoglobin oxygen saturation (sO2) on results of measured FCOHb. Blood from nine healthy non-smokers was tonometered with gas mixtures containing 94% N2 or air and 6% CO2. The resulting oxygenated and deoxygenated specimens were mixed in different proportions to obtain varying sO2 values in the same blood. sO2, fractions of dyshaemoglobins, pO2, pCO2 and pH were measured at each step. FCOHb was significantly (p<0.001) higher in oxygenated (median, range: 0.6%, 0.4-0.9%) compared to deoxygenated (-0.2%, -0.5-0.0%) blood. Regression analysis identified the sO2 as the most important factor explaining 86% of the variance in observed changes in FCOHb. The observed sO2 effect has important implications on calibration procedure of OSM3, accuracy of measured FCOHb, and FCOHb dependent calculations such as estimation of Hb(tot) and related quantities. If the highest accuracy of FCOHb measurement is needed, an sO2 effect on results of measured FCOHb has to be considered and adjusted for.

Determination of circulating hemoglobin mass and related quantities by using capillary blood.

PURPOSE: A standardized carbon monoxide (CO) rebreathing procedure with measurements of CO-hemoglobin, hemoglobin concentration ([Hb]), and hematocrit (Hct) enables to determine total Hb mass (Hb(tot)), blood, erythrocyte, and plasma volume (BV, EV, and PV). These calculations are normally based on venous blood samples. However, micromethods also allow determinations from capillary blood. METHODS: The accuracy of using capillary blood for Hb(tot), BV, EV, and PV determination was evaluated in 42 men (age: 25.1 +/- 4.0 yr, body mass: 80.3 +/- 9.6 kg) by comparison of capillary and venous data. RESULTS: Capillary Hb(tot) (962 +/- 110 g) did not differ from venous values (959 +/- 106 g). Hb(tot) values were highly correlated (r = 0.987, P < 0.001, SEE 18 g). Also, capillary and venous BV, PV, and EV were highly correlated (0.94 < r < 0.98), but slightly different (-2.7 to 0.9%) because of higher capillary than venous [Hb] and Hct. Coefficients of variation of repeated Hb(tot), EV, PV, and BV measurements (3.0-5.2%) were similar in capillary and venous blood. CONCLUSION: Calculation of Hb(tot) using capillary blood is as accurate and reliable as using venous blood.

How valid is the determination of hematocrit values to detect blood manipulations?

UNLABELLED: The aim of this paper is a critical reflection of the practice in competitive cycling to use the hematocrit value (Hct) as an indirect control measure for doping with erythropoietin. To demonstrate the individual physiological variation of Hct values, five different studies were performed: 1) Eight subjects were observed (i) during 23 h after a 1 h lasting bout of cycle exercise at 60% of maximum performance and (ii) during 24h under control conditions. 2) Seven subjects were exposed to a 20 min period of -7 head down tilt (HDT), which was followed by 15 min in sitting position. 3) From four subjects blood samples were taken in a sitting position up to 60 min after they had ingested 1 liter isotonic saline solution. 4) Ten subjects performed a vita maxima test on a cycle ergometer, starting at 100W and increasing the workload by 17W every minute. 5) Four elite cyclists participated in a 10 days competition (1,700 km). RESULTS: 1) During the 24h observation period Hct decreased during the night from 45.3+/-3.1 % to 42.9+/-1.5% and returned to the initial values in the morning. This diurnal variation was even more pronounced after submaximal exercise (-4.1 %). 2) Due to fluid shifts from the interstitial into the intravasal compartment, HDT was accompanied by a 3.1+/-0.5% lower Hct. 3) Drinking of the isotonic saline solution also reduced the hematocrit by 3.3+/-0.5% after one hour. 4) Maximum cycle exercise increased the Hct from 46.8+/-2.4 % to 51.3+/-1.9% which was due to a 15 % decrease in plasma volume. 5) Repeated bouts of cycle-exercise reduced the Hct from 46.4+/-1.5% to 41.3+/-1.6%. CONCLUSIONS: All experiments demonstrate that the Hct is not a constant value but can be considerably changed by physiological measures. Clinical studies show that brain oxygen supply decreases with increasing Hct-values, which are also associated with a higher risk of stroke accidents. We therefore recommend to use a Hct-limit solely under strongly controlled standardized conditions to protect professional cyclists from hazardous manoeuvre until more appropriate methods to detect EPO-doping are developed.

Effect of intravenous dopamine infusion on plasma concentrations of dopamine and dopamine sulfate in men, during and up to 18 h after infusion.

OBJECTIVE: We investigated whether sulfoconjugation contributes to the inactivation of intravenously infused dopamine (DA) in low concentrations with a predominant action on the kidney. METHODS: Plasma DA and dopamine sulfate (DA-S) concentrations were determined during 4 h of intravenous infusion of DA (2 microg/kg/min) and up to 18 h after cessation of infusion. Twenty-seven healthy young subjects participated in the placebo controlled, randomised and double-blind study. RESULTS: Intravenously administered DA was sulfoconjugated rapidly and to a great extent. After starting the infusion, DA levels rose within minutes and reached a steady state after 30-60 min. The steady-state levels averaged 151.3 +/- 8.2 nmol/l. DA-S levels also increased markedly with infusion from 16.7 +/- 9.9 nmol/l at the start of infusion up to 261.2 +/- 24.2 nmol/l at 30 min after cessation of infusion. Plasma DA concentrations after cessation of the infusion decreased rapidly with an initial half-life of elimination of 4.8 min. Concentrations of plasma DA-S declined with a half-life of 4.5 h. Persistent elevations of free and conjugated DA compared with pre-treatment levels were observed even 18 h after cessation. Heart rate and blood pressure remained unchanged both during DA and saline infusion. CONCLUSION: Findings indicate that the sulfoconjugation pathway contributes markedly to the inactivation of intravenously infused DA and seems not to be saturable by DA infusion in low doses.

Plasma-electrolytes in natives to hypoxia after marathon races at different altitudes.

PURPOSE: It is well known that altitude natives differ from sea level natives in aspects of fluid and electrolyte homeostasis. METHODS: To evaluate exercise and environmental influences on the electrolyte and water status in hypoxia adapted subjects, we investigated 11 well-trained marathon runners (33.7 +/- 0.7 yr, 60.5 +/- 1.9 kg), native to an altitude above 2600 m, before and after two marathon races. One competition was held at moderate altitude (AM, 2650 m, 14 degrees C, 55% RH, running time 3 h 6 min +/- 22 min) and another under tropical conditions (HM, 470 m, 28 degrees C, 70% RH, running time 2 h 54 min +/- 30 min). Blood samples were taken 3 d before, immediately after, 1 h after, and 24 h after the races. RESULTS: The loss in body fluid was calculated to be 2.15 L during AM and 5.05 L during HM, respectively. It was compensated mostly by ingested fluids without electrolyte content and by metabolically produced water, which led to hyponatremia during AM (plasma [Na+] from 144.3 +/- 0.7 to 131.7 +/- 2.1 mmol x L(-1)). Severe dehydration without significant changes in plasma [Na+] could be detected after HM. Serum antidiuretic hormone concentrations and serum aldosterone concentrations significantly increased during both races and remained at a high level for at least 1h after both competitions. Serum atrial natriuretic peptide (ANP) concentrations were at a high level at rest, increasing during HM, and decreasing during AM. CONCLUSION: Under tropical conditions, we found a severe state of dehydration characterized by an extended ANP-response, which was not prevented by water intake during the race. Under hypoxic conditions, however, we found that hyponatremia had developed. This can be partly explained by pure water intake and metabolically produced water, and also, possibly, by a special hypoxia-induced effect.