Seasonal variations of hydration status of professional soccer players in Saudi Arabia during training sessions and match play

Alshuwaier, Ghareeb (2017) Seasonal variations of hydration status of professional soccer players in Saudi Arabia during training sessions and match play. PhD thesis, University of Glasgow.

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Soccer is the most widely played sport in the world. Consequently, players train and compete in a wide variety of environmental conditions. Professional soccer players normally train daily and compete once or twice a week. Exercise hot environments can lead to dehydration because sweat losses often exceed fluid intake. Sweat rate can range between 1 to 2.5 L.h-1 depending on factors such as environment conditions, fitness and clothing. Previous studies of soccer players have found that players are often dehydrated.
This thesis consists of three studies conducted in Riyadh, Saudi Arabia. Young Saudi professional soccer players based at the Al Hilal club were recruited to the study. The author worked them during their training and matches at different periods during the year to study the effects of exercise in warm and cool conditions. Their hydration status was studied using a range of methods including analysis of the blood and urine. The main aims of these experiments were to examine the effect of exercise intensity in temperate and hot environments on blood, urine, core body temperature and aldosterone concentrations.
The first study evaluated their hydration status over three days of training and one match in temperate conditions. The aim of this study was to establish that research could be conducted as players went through their normal routines determined by the club management and coaches. Change in body weight, serum osmolality and electrolytes, sweat loss, fluid intake and aldosterone concentrations were measured. The range of ambient temperatures was between 23.4 and 30.6 oC and the relative humidity ranged between 14.2 and 23.2 %. Eleven Saudi professional soccer players participated in this study. Their body weight significantly decreased during exercise. Serum osmolality was always high indicating dehydration. It increased significantly during match play, from pre 288 ± 3 mOsm/kg to 293 ± 4 mOsm/kg. Day by day changes of serum osmolality before training sessions and match were small and on some days statistically significant. Plasma aldosterone concentrations significantly increased after the match. The magnitude of dehydration was affected by the intensity of the training sessions GPS was used to measure distance covered. Players covered more distance in match play (7326 m) than in training sessions. Core body temperature was elevated during exercise but not to dangerous levels.
The second study was aimed to repeat these measurements in the summer time during the early season in September. Again, three training sessions and one match were studied. The environment conditions were above 35 oC on all days and the relative humidity was between 10.5 and 13.0 %. The success of the first study in establishing a good relationship allowed some expansion and sixteen soccer players were recruited. Similar results were obtained and fluid losses were greater in the hotter conditions. None of the players replaced all of the fluid lost in training sessions or match play. The mean of sweat rate was 1932 ± 512 ml.h-1 and players dehydrated by 1.8 ± 0.7 % during match play. The serum sodium concentrations were small but statistically significant for some sessions. Similar changes were seen in serum osmolality. Estimated urine osmolality and specific gravity values were high on all days. Plasma aldosterone concentrations increased significantly during two training sessions and match play. On all days the mean of core temperature during exercise increased significantly.
The third study aimed to improve hydration in a group of players before they started training. Responses were compared in hydration intervention (HI) and hydration control (HC) groups. Each group comprised of eight soccer players. The ambient temperature during this study was about 29 oC. Measurements were taken on three days; the first day was as base line. Next two days, intervention group were instructed to consume 500 ml before attending the club. Independent t-test showed no significant differences between the two groups in base line of age, body weight, height and BMI (P > 0.05). Blood, urine, intensity of exercise, aldosterone and core body temperature were measured between groups. Serum electrolyte concentrations were not different in the two groups on three days. The serum osmolality of HI was significantly lower than HC before training two (T2) during the study (P < 0.05). No differences in fluid intake were observed during training and sweat rate and loss did not differ during training sessions in the two groups. In addition, serum osmolality did not change after T2 in HI, where the control group had significant increase in osmolality after this training session (P < 0.05). On the third day, serum osmolality did not differ between the two groups. However, after exercise serum osmolality elevated from pre to post exercise. The HI group had lower aldosterone concentrations before T2 started than HC group (P < 0.05). The core temperatures rose during exercise in both groups and there were no differences between the two groups.
In conclusion, the three studies were completed successfully. Good data were obtained and it was possible to conduct research with the players as they followed their normal routines of training and playing. These data showed that the players were dehydrated before and during training and match play. Sweat loss was greater in hot conditions than in temperate conditions. Serum osmolality elevated after exercise in hot and temperate conditions and by different intensity of exercise. Plasma aldosterone concentrations were affected by the exercise in all studies.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Hydration, soccer, GPS, and aldosterone.
Subjects: R Medicine > RC Internal medicine > RC1200 Sports Medicine
Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Life Sciences
Supervisor's Name: Baxendale, Dr. Ronald
Date of Award: 2017
Embargo Date: 14 November 2021
Depositing User: Mr Ghareeb Omar Alshuwaier
Unique ID: glathesis:2017-8598
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 14 Nov 2017 14:32
Last Modified: 16 Nov 2020 06:23

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