The practice in the open air with football is under the influence of the weather conditions like showed it several studies (Thein, 1995; Bongbele et al., 1998; Vellerand, 1995) . These studies were conducted in hot environment (temperature > 30˚C), in neutral environment (20˚C - 25˚C) or in cold environment (temperature < 10˚C). Significant variations were noted for body weight, heart rate (HR), blood pressure and internal temperature. Indeed, the human body adapts easily to the climatic fluctuations and expenditure thus more or less of energy to be maintained at the adequate temperature (McArdle et al., 2001) . In equatorial Africa, several football meetings are played during rain. This implies that the physiological adaptations of the organization are specifically influenced by this environment. In neutral environment, a football match comprises intense phases of exercises of long duration intersected with periods of slow races fewer. This alternation suggests a reconstitution of the muscular ATP by the reaction of the phosphocreatin with a possible participation of the anaerobic glycogenolysis, aerobic way intervening during the phases of long duration (Simon et al., 1986; Palca et al., 1986) . On the other hand, in hot time, the particularities are linked on the level of thermoregulation (Buskirk & Grasley, 1987) and the cardiovascular adaptations (Newburgh, 1949) of the organism. With the cold, one notes disturbances of thermoregulatory responses, associated to sympathetic and parasympathetic nervous systems (Constance et al., 2004; Cooper, 2002) .
In Congo (Brazzaville), country located in wet equatorial environment, the organization of the sporting season in football is made conspicuous by a prevalence of the rainy period at the time of the majority of the meetings. Moreover, the rain is often associated to wind; what has, of not to doubt, of the effects over the hydrous losses and the autonomous nervous system (Bongbele et al., 1998; Cooper, 2002) . In the absence of data relating to the Congolese context, the aim of this study is to evaluate body weight variations, haemodynamic and thermoregulatory adaptations of the Congolese football players carrying out meetings in rainy weather. The specific objectives are to determine the variations of body weight, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP0), rectal temperature, coetaneous temperature and internal temperature.
2. Material and Methods
The study, experimental, was carried out in Brazzaville from October 2015 at July 2016. This period comprised at two climatic seasons: October-December (lower rainwater precipitations: 900 mm fallen water) and March-May (higher rainwater precipitations: 1500 mm fallen water) (Clairac, 2000) .
On the whole, 32 football players evolving/moving in the same team of the first national division took part in this study. The criteria of inclusion were: regularity of training, agreement of the technical experts for the participation in the experimentation, morbid absence since 3 months. Their mean age was 22.0 ± 1.7 years (range: 18 - 26 years). The 32 subjects were divided into two teams: team 1 (n = 16 football players); team 2 (n = 16 football players) according to the level of performance. However, only the ten players of field were evaluated in each team. Their ages were comparable. These players have with the precondition undergone a medical examination near a sporting doctor of the Medical center of Brazzaville. This examination included cardiovascular, respiratory, bone health clinical examinations. The anthropometric data of the whole of players are indicated in Table 1.
Experimental procedure team 1 was opposed to team 2 in rainy weather initially, then in no rainy carry. During the period of study, the climatic conditions in situ were recorded at each meeting. In rainy weather, climate data were: average temperature, 28.5˚C; average relative moisture, 75.7%; mean velocity of the wind, 2.2 m/s. In no rainy weather, these values were respectively of 26.3˚C, 67.5% and 1.2 m/s. The rainy weather was defined by the observation of water precipitations higher than 10 mm, whereas the no rainy weather related to a null level of precipitations (Clairac, 2000) . The apparatuses used were pluviometer (model WTW OXY 330, Secchi, Switzerland) to determine the quantity of fallen rainwater (in mm), hygrometer (Raytek, Cologne, Germany), anemometer (Gymrol, Saint-Etienne, France), clinical thermometer for the rectal temperature measurement (Simonsen, standard CR.W2Á, Copenhagen, Denmark). For the coetaneous temperature measurements, they were carried out on the arm, the trunk, the leg and the head using laser thermometers Minitemp (Cosma, Paris,
Table 1. Anthropometric data of football players.
BMI, body mass index.
France). The internal temperature was estimated by the formula of Kuznetz (1979) :
θcent = (0.33 × θcut) + (0.67 × θrect).
The coetaneous temperature was also given by the means of the formulas of Kuznetz (1979) :
θcut = (0.10 × θarm) + (0.60 × θtrunk) + (0.20 × θleg) + (0.10 × θhead).
Six matches were programmed between the two groups. These were carried out during the period of study: 3 in rainy weather and 3 in no rainy weather. All the players were subjected to the same program of training, composed of the following sequences: physical preparation, refinement of technico-tactic skills, organization of a small competition, return to a rest state, debriefing. The duration of each meeting was 3 hours. The system of play of the meetings was the 4-2-4 (Table 2).
The training proceeded between 15:00 pm - 18:00 pm. The meetings proceeded in the same site (Complex Omnisport Massamba Débat).
They were summarized with the determination, before and after each meet: variations of body weight (ΔW in kg), HR (in b/min), SBP (in mmHg), DBP (in mmHg), PP0 (in mmHg), rectal temperature (θrect, in ˚C), coetaneous temperature (θcut, in ˚C) and internal temperature (θcent, in ˚C). Those were evaluated in the ten players of field for each team. At the end of these meetings, all the variations inter seasonal of the various parameters of interest were examined in all the players of field.
2.4. Statistical Analysis
Data were expressed as mean ± standard deviation (SD) or percent. Student t test for weak samples (n < 30) was used for compared two categorical and continuous variables normaly distributed. As for the comparison of values according to the compartment of occupied play, non-parametric test (Mann Whithney) was used. Traditional formula of the descriptive statistics was used for comparing variations between the two groups, for the same compartment (Sokal & Rohlf, 1995) . p-value ≤ 0.05 defined statistical significance. All statistical analyses were performed with Mathcad, version 6.5.1 at the Division of Statistics, Department of Mathematics, Faculty of Sciences and Technology, Marien NGOUABI University of Brazzaville (Congo).
Significant difference was observed between the subjects of two groups on body weight values before and after the matches. In addition, significant losses noted in the players
Table 2. Partitioning of the system of the play.
evolving/moving in rainy weather (Table 3), particularly on second compartment (−5.2%). In addition, the data of Table 3 indicated significant variations of SBP before and after the meetings: +20.8% in rainy ambient versus +14.9% in no rainy ambient.
Variations were higher during rainy weather: 6.6% versus −3.9% (no rainy weather). With regard to HR (Table 4), significant variations were observed before and after the meetings, particularly in favor of the players evolving/moving in rainy weather: 61.3 ± 1.2 b/min versus 65.6 ± 0.4 b/min and according to the compartment of football players. Values of HR were higher in rainy weather before and after the matches (Table 4), all the compartments comprising.
As for PP0 (Table 4), the values noted in no rainy weather were higher, the variations being significant before and afterwards in compartment 3.
Concerning internal temperature, significant differences were perceived before and after the matches. Variations recorded during the meetings were significantly (p < 0.05) lower in the players carrying out of the meetings in rainy weather: +3.5% versus +6.2% in no raining ambient (Table 5).
The aim of this study was to evaluate the variations of the body weight, HR, SBP, DBP, PP0, rectal temperature, coetaneous temperature and internal temperature due to the football practising and physiological stress of the rain in the high level Congolese football players. The key findings of the present study are as follows. Losses of body weight
Table 3. Variations of body weight (in kg) among football players before and after competition according to compartment.
CP, compartment; Δ, difference between values noted before and after competition; *, significant difference at p < 0.05.
Table 4. Variations of haemodynamic values among football players before and after competition.
HR, heart rate; SBP, systolic blood pressure; DBP, diastolic blood pressure; PP0, pulse pressure; Δ, difference between values noted before and after competition; *, significant difference at p < 0.05; ***, significant difference at p < 0.001.
Table 5. Variations of rectal, coetaneous and internal temperatures among football players before and after competition.
θrect, rectal temperature; θcut, coetaneous temperature; θintern, internal temperature; Δ, difference between values noted before and after competition; *, significant difference at p < 0.05.
were significant higher in the footballers carrying out of the meetings of football in rainy weather. Higher variations characterized profile of HR, SBP and various temperatures (rectal, coetaneous and internal) in the players carrying out of the meetings of football in rainy weather. However, several limitations are found in this work. First of all, it should be stressed that the Δy variations recorded before and after, in rainy environment, translate the amplitude of variation of each variable studied under the effect of a double stress (physical and thermal). Thus, they make it possible to quantify it in real measuring unit. Moreover, the parameter speed of variation [yo] measurement the speed of variation induced by a stress in the interval of the activity. We chose the first tendency deliberately in order to describe the evolution of the studied variables, for purposes to clarify the variable of the aforesaid variations at rainy ambient temperature. The second limitation is associated to agreement with the concept of existence of a physiological steady state during the exercise. Concept of steady state or physiological balance to the exercise of maximum intensity indeed induced the positivation of the phenomenon of tiredness. Another limitation is linked to the restriction of sample at football players of Brazzaville’s Department. However, Republic of Congo is divided in 9 departments characterized by variations of climate. So, one wonders to what the conclusions of the present experimental study couldn’t by extrapolated to the general football players population of Congo. However, the force of this work resides on the absence of similar studies in equatorial zone (Africa, America and Asia).
It comes out from this work that the body weight losses were more significant in the players of the medium of the ground: −6.6% in rainy weather and −3.9% in no rainy weather. The role of distributor of the balloon falls to these players. Moreover, to distribute the balloon effectively, it should initially be received and that implies much to run to intercept it or tear off it with the adversary. It follows without any doubt a great expenditure of energy. It was brought back on this subject that the hydrous deficits are pronounced at these stations where the energy expenditure is high (Savalli et al., 2006; Debrinay, 1981) . In addition, according to the system of play, the side ones (compartment 1) can from time to time go up until in attack (compartment 3). The great loss of weight obtained in compartment 1 can be allotted then partly too many long displacements of the side backs, those being sometimes transformed into wingers in order to create an excess in attack. On the other hand, the hitchkiker and the libero (compartment 1) traversed the shortest distances, seldom carrying out the rises; they are the last ramparts before the goalkeeper. Being the attackers (compartment 3), when they are effectively been useful by compartment 2, they often traversed that small distances. However many accelerations, the vertical jumps and the many shootings can explain the loss of weight obtained with compartment 3.
Concerning the heart rate of players evolving/moving in rainy and no rainy environment, it arises that this one is comparable with that of the Congolese sedentaries of Nkoua et al. (2000) : 69.0 b/min (our series) against 70.2 b/min, for a comparable age. Our values are superposable with those noted by Kingué et al. (2001) in the Cameroonians judoists: 71.75 b/min (by echocardiographic method). However, the drive of football requires physical exercises likely to involve a particular adaptation of the haemodynamic system. To this end, several authors report a lower HR as well in the high level footballers as at the majority of the sportsmen, compared to the witnesses (Gurtner et al., 1975; Rowell & O’Leary, 1990; Saltin, 1985) . This lowering is a function not only of one nervous sympathetic hypotonia. Also, dimensions of the higher intervenous cardiac cavities among the sportsmen of elite, at which coexist parietal hypertrophy, increase in the left ventricular mass and left ventricular dilatation (Green et al., 1996; Lash, 1998) . As for SBP, our values join those of Kingué et al. (2001) : 121.5 mmHg ± 12.9 (our series) versus 120.0 mmHg ± 12.1. Concerning HR, it increased on average, during meetings, of +61.4% (p < 0.05) in the players carrying out of the meetings of football in rainy weather against +40.9% in the players carrying out of the meetings of football in no rainy weather. However in the light of these observations, it arises that the cold water of rain exerts a specific influence on the cardiovascular adaptations during sporting meetings being held in rainy environment. Thus, from a rheological point of view, it pay that during a meeting proceeding in times of rain, the incidence of the environment of the environment clearly does not accelerate the phenomena of fast adaptation of the cardiac function à the exercise. Speed with which these adjustments are carried out of is thus limited. On the other hand, this adaptation involves a level of definitely lower HR in thermal condition neutral, but higher than that recorded in cold thermal condition: 137.6 b/min with 20˚C after 95 min of exercise (Fach et al., 1989) against 107.08 b/min in our players.
Moreover, the exposure of all the organization to the rain produces systemic answers which all are indicative of an activity of the nervous sympathetic system (Convertino, 1991; Hayward, 1977) . In addition, the stimulation of the nervous sympathetic system appears in times of rain by an increase in SBP and DBP (Convertino, 1991) , by a rise of HR (Convertino, 1991) , like by a change of the cardiac flow (Green et al., 1996) . These reactions are typical cooling of the distal parts. However, the exposure of the figure to rainwater, in equatorial climate, also brings a tachycardia related to a lifting of vagal inhibition; what explains the no significant rise in the blood pressure by reduction of the peripheral blood flood to the profit of an adequate central circulation. Moreover, rises in SBP and DBP in the players evolving/moving in rainy weather can be also explained by the relations of Fagard (Fagard, 1985) , connecting the blood pressure noted to the beginning of the match with the intensity of work. As for the rectal temperature, it increased on average, during meetings, of +7.7% in the players carrying out of the meetings of football in rainy weather against +3.2% in no rainy weather, the difference being significant (p < 0.05). The weak variations observed are undoubtedly ascribable by character little differentiated from the dissipative function of energy [Q−1] for the whole of the cardiorespiratory system. These factors thus contributed in a way significant to cause a considerable hydrous loss by sudation, contrary to the subjects evolving/moving in rainy weather.
Lastly, with regard to the temperatures coetaneous and central, they differ significantly in rainy and no rainy weather. Moreover, Cissé et al. (1997) concern in young Senegalese sportsmen comparable age, a change of the coetaneous temperature (thorax) and intern, in no rainy weather and heat: θcut = 35.31˚C ± 0.52˚C and θrect = 37.29˚C ± 0.40˚C. Our observations confirm a well-known concept: the coetaneous temperature varies with the ambient temperature (Benzinger, 1969; Casa, 1999) . The thermal rise caused by rainwater is in relation to the more increased activation of the nervous sympathetic system. Indeed, catecholamines stimulate the use of the muscular system and the production of lactates. The values of the internal temperature are less low at our subjects in rainy weather. Thus, the internal temperature is in relation to the ambient temperature. However, one should not neglect in rainy weather the role of thermogenesis induced by the acclimatization (Prentice, 2003; King et al., 1985) . Moreover, one precise determination of the internal temperature is related on the coetaneous temperature and the rectal temperature as Kuznetz (1979) bring it back. Indeed, the first which translates the mechanisms of thermoregulation better carries out by the use of a relation taking of account the temperatures of the face, the chest, the leg and the thigh, in accordance with the methodology of Savalli et al. (2006) . All things considered, the variations in the coetaneous temperature, rectal temperature and central temperature during meetings in rainy weather are of not to be doubted due to the increase in the rate of adrenalin in blood.
The present study has showed that rainy environment modified body weight, haemodynamic adaptations and thermoregulatory profile in the football players in Congolese equatorial climate. These variations were more significant in the players evolving/moving in rainy weather, in particular at those of the medium of the ground. Thus, it is advisable to acclimate the footballers in rainy ambient for minimizing the stress of training in such environment.
 Clairac, B. (2000). Climate of the Area of the Pool-Brazzaville. In: Senechal, A., Kabala, M. and Baker, R., Eds., Review of Knowledge on the Climate of Congo-Brazzaville, UNESCO-UNDP, Paris, 45-68.
 Savalli, L., Olave, P., Hernandez Sendin, M. I., Laboute, E., Trouvé, P., & Puig, P. L. (2006). Whole-Body Cryotherapy -110℃. Measure of Skin and Central Temperature to the Sports- man. Science & Sports, 21, 36-38.