Age and gender related changes in hematological parameters of thoroughbred foals

Abstract

Hematological and biochemical profiles commonly are required in equine medicine. We studied hematological parameters including red blood cells (RBC), white blood cells (WBC), hemoglobin (Hb), hematocrit (PCV), differential leukocyte counts, mean cell volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) in thoroughbred foals at different ages and for both sexes. Sixty healthy thoroughbred foals, 1 day, 3 days and 1 year old were used. Each age group consisted of 10 male and 10 female animals. We found significant differences related to age in RBC values of females, PCV, MCV values of males, WBC, neutrophil percentages, lymphocyte percentages, monocyte percentages of females, and eosinophil percentages and basophil percentages. Significant differences related to gender were found only with regard to PCV at 1 year and WBC at 1 day. The hematological parameters of thoroughbred foals up to one year old may be useful for evaluating and monitoring the health of these animals.     

Seasonal changes in the haematological indices in peripheral blood of chinchilla (Chinchilla laniger L.)

Changes in nine haematological indices in adult female and male chinchilla were investigated over a period of 18 months. All haematological values were in the same range both for females and males, although seasonal fluctuations were more evident in the females. High levels of the red blood cells count (RBC), haemoglobin concentration (Hb), mean cell haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) during the winter months and low levels of these parameters during the summer months were found. The white blood cells count (WBC) and lymphocyte number (L) also decreased in summer, their values increasing during autumn and spring. The haematocrit values (Ht) and mean cell volumes (MCV) are high during the summer and low during the winter.     

Haematological profile of common carp spawners of various breeds

The goal of this study was to determine the basic haematological profile of common carp (Cyprinus carpio L.) spawners of eight breeds reared under identical conditions and sampled in spring after overwintering. Significant differences were found among the breeds for haemoglobin level (Hb), haematocrit value (PCV), mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH) values. The number of red blood cells (RBC), mean corpuscular haemoglobin concentration (MCHC), number of leukocytes (WBC) and leukocyte differential count (WBC DIFF) did not differ significantly among the respective breeds. The highest Hb, PCV and MCH values were found for Ropsha scaly carp (ROP) and Amur wild carp (AS) (Hb 109 ± 17 and 106 ± 15 g l^?1; PCV 0.40 ± 0.06 and 0.40 ± 0.06 l l^?1; MCH 69 ± 7 and 69 ± 9 pg, respectively). The AS specimens and breeds that originated [ROP, Ukraine scaly carp (US), and Northern mirror carp (M72)] showed significantly higher values of Hb (P < 0.01), PCV (P < 0.01), MCV (P < 0.05) and MCH (P < 0.05), compared to the other four breeds: Hungarian mirror carp (M2), Israeli mirror carp (Dor 70), South Bohemian mirror carp (BV) and Tata scaly carp (TAT). Males showed significantly higher PCV, Hb and RBC values within individual breeds. This study demonstrated that Amur wild carp and breeds originating from it had significantly higher values of erythrocyte profile in comparison with the other breeds studied.     

Mature hematology in neonatal walruses supports diving alongside their mothers

An animal's physiology limits the environmental conditions where it can persist; quantifying the physiology of the walrus is timely since they are being impacted by alterations in sea ice. We examined postnatal changes in hematology, an important attribute that supports diving, by analyzing a longitudinal data set from aquaria walruses (five males and nine females) sampled from 0.04 to 12.0 years of age (n = 795 samples). Red blood cell count (RBC), hemoglobin (Hb), hematocrit (Hct), mean corpuscular volume (MCV), mean cell hemoglobin (MCH), and mean corpuscular hemoglobin content (MCHC) did not change markedly after birth and appears to have not been influenced by sex. Estimated values at birth were RBC: 3.78 ± 0.12 × 10⁶ mm⁻³, Hb: 17.62 ± 0.82 g dl⁻¹, Hct: 45.21 ± 2.01%, MCV: 118.99 ± 3.99 fl, MCH: 47.10 ± 1.77 pg, and MCHC: 39.60 ± 0.70 g dl⁻¹. Compared to newborns, there were only subtle decreases in RBC, Hb, and MCHC, and a slight increase in MCV in the years following birth; Hct and MCH appear not to have changed. Unlike other pinnipeds, walruses swim within days of birth and have a prolonged 2-year nursing interval. Mature hematology early in life supports breath-holding, as young walruses must transit under sea ice with patchily distributed breathing holes.     

Haematocytometrical changes in chicken blood to acute 60Co gamma radiation

Newly hatched white leghorn chicks (Gallus domesticus) subjected to single whole body 2.25 Gy (225 rads) gamma radiation exposure at the dose rate of 0.50 Gy/sec (50 rads/sec), were studied for changes in a number of haematological parameters at days 1,3,5,7,14 and 28 post irradiation during development. The sudden decline and gradual recovery in total RBC and WBC counts and the level of Hb and Hct along with MCV, MCH and MCHC values evaluation indicates a high regenerative capability of leghorn chicks.     

Cadmium induced MTs synthesis via oxidative stress in yeast Saccharomyces cerevisiae

Lignan complex has been isolated from flaxseed. It has been shown to reduce serum lipids and the extent of hypercholesterolemic atherosclerosis. However, it is not known whether the chronic use of lignan complex has any adverse effects on the hemopoietic system. The effects of lignan complex (40 mg/kg body wt orally daily for 2 months) on the red blood cells (RBC) count, mean corpuscular volume (MCV), red cell distribution width (RDW), hematocrit (Hct), hemoglobin (Hb), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and counts of white blood cell (WBC), granulocytes, lymphocytes, monocytes and platelet, and platelet volume were investigated in normo- and hypercholesterolemic rabbits. The results show that lignan complex had no adverse effects of counts of RBC, WBC, granulocytes, lymphocytes, monocytes and platelet in both the normo- and hyper-cholesterolemic rabbits. The values for MCV, RDW, Hct, Hb, MCH, MCHC, and platelet volume were similar in lignan complex-treated or untreated normo- and hypercholesterolemic rabbits. It is concluded that chronic use of lignan complex had no adverse effects on the hemopoietic system. (Mol Cell Biochem 270: 139–145, 2005)     

Hematological parameters of Caspian salmon Salmo trutta caspius associated with age and season

Measurement of hematological parameters for Caspian salmon Salmo trutta caspius in two experimental trials was the main purpose of this work. There were no significant differences in RBC and large-lymphocyte counts between all seasons (p > 0.05). The proportions of monocyte, neutrophile and eosinophile were higher in winter than in other seasons (p < 0.05). The amount of Hb, RBC, MCHC, monocyte, neutrophile and eosinophile was higher in adult fishes in comparison with other ages (p < 0.05). However, the amount of HCT, WBC, MCV, MCH, lymphocyte and large-lymphocyte was greater in smolt fishes than the others (p < 0.05).     

The effect of exercise and zinc supplement on the hematological parameters in rats

This study evaluates the consequences of a session of intensive short-duration exercise and Zn supplementation on different hematological variables. Forty male Wistar rats were divided into four groups (n=10): the first nonsupplemented, maintained at rest (R); the second nonsupplemented, undergoing exercise (E); the third supplemented with Zn, kept at rest (ZnR); and the fourth supplemented with Zn, undergoing exercise (ZnE). Zinc supplements (200 ppm) were given in drinking water. The exercise consisted of a single session of swimming until exhaustion. At rest, RBC, Hb, and Hto fell (p<0.05), whereas red cell indices, MCV, and MCH rose (p<0.05) in +ZnR compared with R; MCHC remained unchanged (ZnR vs R). After exercise, RBC, Hb, and Hto increased significantly in E and in ZnE compared with R and ZnR, respectively. In addition, RBC and Hb were lower (p<0.01) in ZnE compared with E; however, MCV and MCH were higher (p<0.05) in the group ZnE vs E. With respect to white blood cells—leukocytes (WBC), limphocytes (LYMPH), and neutrophiles (NEUT)—no significant differences were observed between groups at rest (ZnR vs R). WBC and LYMPH increased significantly in E with respect to the rest situation (E vs R), but this did not happen in supplemented animals (ZnE vs ZnR). Level of pH decreased after exercise both in E and in ZnE, but the fall was lower in the latter. We believe that a single session of swimming until exhaustion leads to an increase in RBC, Hb, and Hto without causing changes in MCV, MCH, and MCHC. On the other hand, Zn supplementation leads to an increase of MCV and MCH, although they remain within normal levels. Furthermore, this supplementation produces lower metabolic acidoses after exercise that leads to leukocyte stability.     

Age, sexual and seasonal differences of haematological values and antibody status to Chlamydophila sp. in feral and racing pigeons (Columba livia forma domestica) from an urban environment (Zagreb, Croatia)

The aim of this study was to determine the basic haematological parameters in feral and racing pigeons and to compare these parameters according to age, sex and season in healthy feral pigeons as well as between Chlamydophila-serologically positive and negative feral pigeons. Red blood cells (RBC), packed cell volume (PCV), haemoglobin (Hb), mean cell volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), white blood count (WBC), thrombocyte count and differential WBC, were determined in 366 pigeons (Columba livia forma domestica) captured in the City of Zagreb between 1999 and 2002. Of these, 232 feral (179 adult and 53 juvenile, 104 male and 75 female) and 57 racing pigeons (25 male and 32 female) were clinically healthy and bacteriologically and serologically negative, but 77 birds had antibody titres against Chlamydophila sp. Significantly lower values of RBC, PCV, Hb, MCH, WBC and thrombocyte (P<0.05) were observed in young compared to adult pigeons, while the differences in MCV and MCH were not significant between age classes. In differential WBC of young pigeons, a significantly higher percentage of heterophils, eosinophils, basophils and monocytes and a significantly smaller percentage of lymphocytes (P<0.01) was found than in adult pigeons. Significant sex-related differences were seen only in MCV values and in the percentage of lymphocytes (higher in females) and neutrophils (higher in males). PCV, Hb, MCV and MCH increased, while WBC decreased during wintertime (P<0.05). In differential WBC, percentage of heterophils was low in summer and autumn. At the same time, a higher percentage of basophils was found. Low numbers of monocytes were found in summer and low values of eosinophils in winter. In racing pigeons, values of eosinophils and basophils were significantly lower than in feral pigeons. Pigeons which had antibodies against Chlamydophila sp. possessed a higher percentage of monocytes and less lymphocytes than sero-negative animals, while WBC was significant lower than in sero-negative feral pigeons.     

Changes in hematological parameters in free-living pigeons (Columba livia f. urbana) during the breeding cycle

The blood parameters—red blood cell (RBC) count, hematocrit (Ht), hemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC)—were studied for the first time in free ranging pigeons Columba livia f. urbana. The aim of the study was to establish a set of reference values for this ubiquitous urban species and to examine a potential influence of the factors such as sex and phase of the breeding cycle on the hematological parameters. Blood was sampled from the adult individuals of both sexes during the breeding cycle. Significant variations in Ht and Hb were observed, while RBC count remained unchanged. The lower hematocrit value and hemoglobin concentration found in both males and females during molt probably resulted from the increase of plasma volume not accompanied by an increase in RBC. On the other hand, a significant physiological stress of nutritional deficiency during this energy-consuming stage may manifest itself in the decreased Ht and Hb values. The higher values of Ht and Hb during the laying phase could be related to the dehydration status. There were no overall differences in MCV, MCH, and MCHC values in either of the breeding stage. A lack of sex dimorphism in the measured and calculated blood parameters was apparent. Data collected herein contribute to the better understanding of general physiology of the ubiquitous urban species. The knowledge of variation in the blood indexes with respect to sex and breeding stage is crucial before blood parameters can provide an useful information on physical condition of the bird.     

Haematological studies on the prewintering and wintering frog, Rana esculenta

1. A study of the haematology of the frog Rana esculenta including erythrocyte count (RBC), haemoglobin content (Hb), haematocrit (HCT), mean cell volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) and erythrocyte size as a function of prewinter and winter was made. 2. The RBC count and Hb were significantly higher in contrast to MCV and MCH values during prewinter in both sexes. 3. The surface area to volume ratio was higher in prewinter whereas the length to width ratio (eccentricity) of the cytosome and nucleus was significantly higher during winter in both sexes. 4. Sexual differences in the erythrocyte count, Hb content and the surface area to volume ratio were also observed. 5. The physiological significance of these observations are reported for Rana esculenta.     

Normal hematological values of the African neonate

A longitudinal study of normal hematological values of the newborn infant was undertaken in an effort to provide baseline data for assessing the African Neonate with hematological problems. There were 402 neonates, consisting of 304 full-term, 51 preterm and 47 post-term infants. The Hematocrit (Hct), Hemoglobin (Hb), Red Blood Cell Count (RBC), Reticulocyte count (Retic) and Nucleated Red Blood Cell Count (NRBC) were serially determined. The red cell indices, Mean corpuscular Hemoglobin (MCH), Mean Corpuscular volume (MCV) and Mean corpuscular Hemoglobin Concentration (MCHC) were calculated for each neonate. Our results showed that African neonates have lower hematological values than their North American and European counterparts. This was neither a reflection of an intrauterine anemia nor was it due to variables resulting from the timing of cord blood sampling. On the first day of life, the mean Hct was 45.4%; mean Hb was 15.46 gm/dl; and the RBC was 4.02 X 10(6) cells/mm2. The Retics, NRBC and other red blood cell indices do not differ from those of neonates reported from other parts of the world. We suggest therefore that the low hematological values of the African neonate may be intrinsic.     

Effect of chronic administration of vitamin E on the hemopoietic system in hypercholesterolemia

Hypercholesterolemia induces oxidative stress, which is known to have adverse effects on the integrity of cells. Hence, hypercholesterolemia may have adverse effects on the hemopoietic system. Vitamin E, an antioxidant, is being used by normo- and hypercholesterolemic subjects. It is, however, not known if vitamin E has any beneficial or adverse effects on the hemopoietic system. The objectives of this study are to determine if (i) hypercholesterolemia has any adverse effects on the hemopoietic system [red blood cell (RBC) count, mean corpuscular volume (MCV), red blood cell distribution width (RDW), hematocrit (Hct), hemoglobin (Hb), mean corpuscular hemoglobin (MCH), MCH concentration (MCHC), white blood cell (WBC), and platelet counts, and mean platelet volume (MPV)], and (ii) vitamin E has any effect on the hemopoietic system in hypercholesterolemia. Blood samples were collected before and at various intervals during a high cholesterol diet (0.25% cholesterol) for 2 and 4 months, and while on high cholesterol diet with vitamin E (2 months) following a high cholesterol diet (2 months). Serum cholesterol was measured on an automated Clinical System Analyzer and hemopoietic parameters were measured on an automated Cell-dyn-4000. The results show that hypercholesterolemia decreased RBC count, Hct and Hb, increased MCV, RDW, MCH, and MCHC, and had no effect on WBC and platelet counts, and MPV. Vitamin E did not affect any of the parameters of the hemopoietic system. In conclusion, hypercholesterolemia of short duration has adverse effects on certain elements of the hemopoietic system. Vitamin E does not affect the hemopoietic system during hypercholesterolemia.     

Characterization of blood cells and hematological parameters in Cichlasoma dimerus (Teleostei, Perciformes)

The aim of the present study was to obtain a basic knowledge of the hematology of Cichlasoma dimerus. The morphological features of blood cells were described according to the observations made by light and electron microscopy. Erythrocytes, thrombocytes and four types of leucocytes: lymphocytes, monocytes, heterophils and eosinophils, were distinguished and characterized. Thrombocytes are the most abundant blood cells after erythrocytes and are recognized easily from lymphocytes by morphological features and size. Heterophils and eosinophils are PAS positive. Hematological indices (RBC, WBC, PCV, Hb, MCV, MCH, MCHC and leucocyte differential count) were measured in one blood sample from 30 adult fish captured in Esteros del Riachuelo, Corrientes, Argentina (27 degrees 25'S, 58 degrees 15'W). The reference interval and the mean were determined for each hematological parameter evaluated. Contrary to other species, the percent of heterophils was found to be high in relation to the percent of lymphocytes. Low lymphocyte counts occurred in C. dimerus, as compared to these found in other fishes. Compared to most teleosts, this species has similar mean values for PCV and Hb and slightly higher for RBC. Statistical analysis revealed that differences in hematological parameters between male and female fish were not significant.     

Effect in vivo of atrazine on haematology and O2 consumption in fish, Tilapia mossambica.

Studies were conducted on haematological constituents such as Red blood cells (RBC), White blood cells (WBC), Haemoglobin (Hb), Packed cell volume (PCV), Mean cell volume (MCV), Mean corpuscular haemoglobin (MCH), Mean corpuscular haemoglobin concentration (MCHC), Blood volume (BV), Blood water content (BWC) and Whole animal oxygen consumption (WAOC) in the fish exposed to sublethal concentration of atrazine. Significant changes were seen in the constituents of the blood and O2 consumption of fish suggesting the existence of respiratory distress in the fish as a consequence of atrazine toxicity.     

Changes in hematologic values in 11 months after birth in the cynomolgus monkeys

Changes in hematological values were studied with 131 healthy cynomolgus monkeys aged less than 11 months. The parameters measured were erythrocyte count (RBC), hematocrit value (Ht), mean corpuscular volume (MCV), hemoglobin concentration (Hb), total leucocyte count (WBC), and differential leucocyte count. No remarkable change was found with RBC during the whole period of this study. Relatively high values were obtained with Ht, MCV, and Hb in the newborns aged 0 to 7 days. These values continued to decrease until 3 months of age, after which the values increased again attaining approximately adult levels at 11 months of age. WBC was very high at birth and then decreased to the minimum level at 3 days of age. It was followed by gradual increase until about 4 months of age at which a nearly adult level was attained. Lymphocyte counts were smaller than neutrophil counts on the day of birth. However, this numerical relation was inverted 2 days after birth and the lymphocyte counts became markedly larger than the neutrophil counts about 1 week after birth. Additionally, the values obtained from the cord blood of 6 Cesarean-delivered newborns were compared with those from the blood taken 5 hours after cesarean delivery.     

Development of hematological respiratory variables in late chicken embryos: the relative importance of incubation time and embryo mass

Oxygen demand increases during embryonic development, requiring an increase in red blood cells (RBCs) containing hemoglobin (Hb) to transport O(2) between the respiratory organ and systemic tissues. A thorough ontogenetic understanding of the onset and maturation of the complex regulatory processes for RBC concentration ([RBC]), Hb concentration ([Hb]), hematocrit (Hct), mean corpuscular indices (mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration ([MCHb])) is currently lacking. We hypothesize that during the last half of incubation when the respiratory organ (the chorioallantoic membrane) envelops most of the egg contents, mean corpuscular indices will stabilize. Accordingly, Hct, [RBC] and [Hb] must also all change proportionally across development. Further, we hypothesize that the hematological respiratory variables develop and mature as a function of incubation duration, independently of embryonic growth. As predicted, a similar increase in Hct (from 18.7±0.6% on day 10 (d10) to 34.1±0.5% on d19 of incubation), [RBC] (1.13±0.03×10(6)/μL to 2.50±0.03×10(6)/μL) and [Hb] (6.1±0.2 g% to 11.2±0.1 g%) occurred during d10-19. Both [RBC] and [Hb] demonstrated high linear correlation with Hct, resulting in constant [MCHb] (~33 g% from d10 to d19). The decrease in MCV (from ~165 μ(3) on d10 to ~140 μ(3) on d13) and MCH (~55 pg to ~45 pg) during d10-13, may be attributed to a changeover from larger primary to smaller secondary and adult-type erythrocytes with MCV and MCH remaining constant (~140 μ(3) and ~45 pg respectively) for the rest of the incubation period (d13-19). Hematological respiratory values on a given incubation day were identical between embryos of different masses using either natural mass variation or experimental growth acceleration, indicating that the hematological variables develop as a function of incubation time, irrespective of embryo growth.     

Hematology of a natural population of toque macaques (Macaca sinica) at polonnaruwa,Sri Lanka

Hematological studies were conducted in three wild groups of toque macaques (Macaca sinica) inhabiting the Polonnaruwa Sanctuary in northeastern Sri Lanka. The macaques were temporarily trapped and anesthetized, and femoral blood was drawn from 35 males and 37 females (age range: 0.33-24.5 yr). Statistically significant (P<0.05) differences were observed by sex for total plasma proteins (PP), and by age for red blood cell (RBC) counts, hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular Hb (MCH), mean corpuscular Hb concentration (MCHC), PP, erythrocyte sedimentation rate (ESR), differential and absolute neutrophil counts, differential lymphocyte counts, and absolute eosinophil counts. In general, the results were similar to those reported for other species of colony-bred and free-ranging macaques. However, there also were differences. First, in contrast to earlier studies of nonhuman primates, we examined the hematology of infants. Compared to other age classes, infants (<1 yr old) had lower RBC, Hb, MCHC, and ESR values, and a higher MCV. These findings were similar to those obtained in human infants. Second, we observed variations in hematology among social groups in relation to their ecology. Two groups (IH3 and M3) had ready access to water throughout the dry season (the period of sampling), whereas the third group (J) did not. The Hb, RBC, and PP values obtained in groups IH3 and M3 were similar to those reported in other macaque species. However, these parameters in group J were significantly (P<0.01) higher, which suggests that this group (representing about 26% of the sample) had been dehydrated during the dry season. Finally, two indices indicative of injury and infection--the ESR and leukocyte counts--were higher in the wild toque macaques than has been reported for other species of macaques held in captivity, and about 15% of the toque macaques sampled had extreme outlier values for these parameters; however, none were visibly ill or died. These results suggest that wild toque macaques are subject to a wide array of physical and biological insults that are unique to natural populations.     

微量元素五项联合红细胞四项检测在小儿缺铁性贫血中的诊断价值

目的:探讨微量元素五项联合红细胞四项检测在小儿缺铁性贫血(IDA)中的诊断价值。方法:选取2013年1月至2016年1月于我院进行治疗的小儿缺铁性贫血(IDA)患儿130例作为缺铁性贫血(IDA)组及同期于我院进行常规体检的健康儿童40例作为对照组。检测和比较其钙、镁、铜、铁、锌、血红蛋白(Hb)、平均红细胞体积(MCV)、平均血红蛋白含量(MCH)、平均血红蛋白浓度(MCHC)水平,并比较微量元素五项、红细胞四项检查以及两者联合对IDA患儿的诊断效能。结果:缺铁性贫血(IDA)组患儿微量元素镁、铁、锌含量以及Hb、MCV、MCH及MCHC水平均明显低于对照组儿童,差异具有统计学意义(P0.05);两组儿童微量元素钙、铜含量比较差异不显著(P0.05)。微量元素五项联合红细胞四项的灵敏度、特异度、阳性预测值及阴性预测值均明显高于微量元素五项和红细胞四项(P0.05)。结论:IDA患儿微量元素镁、铁、锌含量以及Hb、MCV、MCH及MCHC水平较低,微量元素五项联合红细胞四项检测可以提高小儿IDA的检出率。     

Hematological variations at rest and during maximal and submaximal exercise in a cold (0°C) environment

The affect of negative thermal stress on hematological variables at rest, and during submaximal (sub ex) and maximal exercise (max ex) were observed for young males who volunteered in two experimental sessions, performed in cold (0°C) and in normal room temperature (20°C). At rest, hematological variables such as RBC and derivates Hb and Hct were significantly increased (P<0.05) during cold stress exposure, while plasma volume decreased. The findings of this study suggest that the major factor inducing hypovolemia during low thermal stress can be imputed to local plasma water-shift mechanisms and especially to a transient shift of plasma water from intrato extravascular compartments. Rest values for WBC and platelets (Pla) were also slightly increased during cold stress exposure. However this increase can partly be related to hemoconcentration but also to the cold induced hyperventilation activating the lung circulation. Maximal exhaustive exercise induced, in both experimental temperatures, significant (P<0.05) increments of RBC, Hb, Hct, and WBC while plasma volume decreased. However, Pla increase was less marked. On the other hand, cold stress raised slightly the observed variations of the different hematological variables. Submaximal exercise induced a similar, though non-significant, pattern for the different hematological variables in both experimental conditions. Observed plasma volume ( PV%) reduction appears during exercise. However cold stress induced resting plasma volume variations that are transferred at every exercise level. Neither exercise nor cold inducement significantly modified the hematological indices (MCH, MCV, MCHC). In conclusion hematological variables are affected by cold stress exposure, even when subjects perform a physical activity.