The effects of carbohydrate supplementation on ...

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The effects of carbohydrate supplementation on immune responses to a soccer-specific exercise protocol N.C. Bishop, A.K. Blannin, P.J. Robson, N.P. Walsh & M. Gleeson Version of record first published: 09 Dec 2010.

To cite this article: N.C. Bishop, A.K. Blannin, P.J. Robson, N.P. Walsh & M. Gleeson (1999): The effects of carbohydrate supplementation on immune responses to a soccer-specific exercise protocol, Journal of Sports Sciences, 17:10, 787-796 To link to this article: http://dx.doi.org/10.1080/026404199365506

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Jour nal of Sports Sciences, 1999 , 17, 787± 796

The eV ects of carbohydrate supplementation on immune responses to a soccer-speciW c exercise protocol N.C. BISH OP, A.K . BLAN N IN , P.J. RO BSO N, N.P. WALSH and M . GLEESON * School of Sport and E xercise Sciences, U niversity of B ir m ingham , E dgbaston, B ir m ingham B 15 2TT, U K

Downloaded by [Bangor University] at 09:45 20 October 2012

Accepted 1 August 1999

The aim of this study was to determine the e V ect of carbohydrate (CHO) versus placebo (PLA) beverage consumption on the immune and plasm a cortisol responses to a soccer-speciW c exercise protocol in 8 university team soccer players. In a randomized, counterbalanced design, the players received carbohydrate or placebo beverages before, during and after two 90 m in soccer-speciW c exercise bouts (3 days apart) designed to m imic the activities performed and the distance covered in a typical soccer m atch. Blood and saliva samples were collected - 1 before, during and after the exercise protocol. Plasm a lactate concentration increased to ~ 4 mmol ´ l at 45 and 90 min of exercise in both treatments ( P < 0.01). Plasma glucose concentration was signiW cantly lower after 90 m in of exercise with ingestion of the placebo than the carbohydrate (PLA: 4.57 ± 0.12 mm ol ´ l- 1; CH O: 5.49 ± 0.11 mmol ´ l- 1; P < 0.01). The pattern of change in plasma cortisol, circulating lymphocyte count and saliva immunoglobulin A secretion did not di V er between the carbohydrate and placebo trials. Blood neutrophil counts were 14% higher 1 h after the placebo trial than the carbohydrate trial (PLA: 4.8 ± 0.5 ´ 10 9 cells ´ l- 1 ; CH O: 4.2 ± 0.5 ´ 10 9 cells ´ l- 1 ; P = 0.06), but the treatm ent had no e V ect on the degranulation response of blood neutrophils stimulated by bacterial lipopolysaccharide. We conclude that, although previous studies have shown that carbohydrate feeding is e V ective in attenuating immune responses to prolonged continuous strenuous exercise, the same cannot be said for a soccer-speciW c interm ittent exercise protocol. When overall exercise intensity is moderate, and changes in plasm a glucose, cortisol and imm une variables are relatively small, it would appear that carbohydrate ingestion has only a minimal in X uence on the imm une response to exercise. K eyw ords : cortisol, immune, imm unoglobulin, leucocyte, neutrophil, saliva, soccer.

Introduction An increasing scienti W c body of evidence suggests that athletes involved in heavy schedules of training and com petition are m ore susceptible to upper respiratory tract infection than their m ore sedentary counterparts (Peters and Batem an, 1983; N iem an et al., 1990). In support of this, m any studies have shown that various aspects of im m une function are tem porarily suppressed follow ing strenuous exercise (for recent review s, see Pedersen and Bruunsgaard, 1995; Shephard, 1997). T his eV ect m ay be m ediated via the actions of stresshorm ones, particularly glucocorticoids and catecholam ines. Recent studies (Nehlsen-C annarella et al., 1997; N iem an et al., 1997a,b; Gleeson et al., 1998) have show n that the ingestion of carbohydrate before and at regular inter vals during prolonged exercise * Author to whom all correspondence should be addressed. e-m ail: m .gleeson@ bham .ac.uk Jour nal of Sports Sciences ISSN 0264-041 4 print/ISSN 1466-447 X online Ó

attenuates m any of the im m unosuppressive eV ects of the activity itself. It is probable that part of the underlying m echanism behind these responses is the attenuation of the cortisol response to the exercise, owing to the m aintenance of plasm a glucose concentrations. H owever, the eV ects of carbohydrate feeding on the im m une responses to interm ittent exercise have yet to be investigated, even though carbohydrate feeding has been show n to be bene W cial during sports involving high-intensity interm ittent exercise that cause fatigue through glycogen depletion (C oyle, 1992). In addition, it has been show n that circulating leucocyte num bers are elevated after 45 m in of both m oderate- (50% VÇ O 2max ) and high-intensity (80% VÇ O 2max ) exercise (Nieman et al., 1993, 1994). High-intensity exercise has also been associated with elevated plasm a cortisol and reduced lym phocyte proliferative responses to phytohaem agglutinin; these eV ects are attenuated when carbohydrate drinks are consum ed during the activity (H enson et al., 1998). Taylor & Francis Ltd


788 Interm ittent exercise is characterized by highintensity activity punctuated by short periods of exercise at a lower intensity or by rest, as occurs in soccer. Exercise intensity and energy expenditure are increased by frequent short bouts of acceleration, sprinting, turning and jum ping. According to Shi and GisolW (1998), the high intensity of exercise during interm ittent activity m eans that sweat losses and glycogen depletion are at least as great as those obser ved during continuous exercise over a sim ilar period of tim e. Therefore, the need to ingest a carbohydrate beverage during interm ittent exercise to m aintain high perform ance m ay be even greater than during continuous exercise over a sim ilar period of tim e. T he m ean relative work rate in soccer has been reported to be around 70% of m axim al oxygen uptake (VÇ O 2 max ; Bangsbo, 1994), and a signiW cant increase in plasm a cortisol concentration com pared with pre-m atch values has been reported in Italian sem iprofessional players (C arli et al., 1986). In addition, a progressive depression of neutrophil function has been reported throughout a season in professional Belgian First D ivision soccer players (Bury et al., 1998). Taken together, it would appear that this type of exercise could have im m unosuppressive eV ects that m ay be attenuated by regular ingestion of carbohydrate beverages. T he aim of the present study was to establish the inX uence of regular ingestion of a carbohydrate beverage on hum oral and im m unological responses to a prolonged bout of interm ittent exercise that sim ulates the pattern of play in a soccer m atch.

M ethods Participants Eight healthy m ales (m ean ± s xÅ : age 21 ± 1 years, height 183 ± 2 cm, body m ass 78.1 ± 2.3 kg), all m em bers of a university soccer team , volunteered to participate in the study. All participants provided written inform ed consent before the study, w hich was approved by the local ethics com m ittee. T hey reported no sym ptom s of infection and were not taking any m edications in the 6 weeks before the study.

Experimental procedures The par ticipants com pleted two exercise trials, each separated by 3 days. T he order of the trials was random ized. Im m ediately before, during and after the exercise trials, X uid intake was as follow s: In the carbohydrate treatm ent, par ticipants consum ed 400 m l of a lem onXavoured glucose solution (6% w /v) 10 m in before the start of each 45 m in of exercise and at 5 m in postexercise; a further 150 m l of this solution was consum ed

B ishop et al. 14 and 29.5 m in into each period of exercise. In the placebo treatm ent, the participants consum ed equal volum es of a lem on-X avoured placebo drink (containing aspartam e as a sweetener) at the sam e tim es as in the carbohydrate treatm ent. T he par ticipants repor ted to the laboratory at 09.00 h on each occasion, after an overnight fast, and were required to em pty the bladder before body m ass (wearing shorts only) was m easured. They were then seated quietly for 10 m in during which a 2 m in unstim ulated saliva collection was obtained using a salivette swab (Sarstedt, N m brecht, G erm any) placed under the tongue. A blood sam ple (11 m l) was then taken from an antecubital vein by venepuncture. At this stage, 400 m l of the prescribed drink was consum ed and the participants sat quietly for a further 5 m in, before m aking their way to the training pitch w here the exercise trials were to take place. Each trial com prised two 45 m in periods of interm ittent exercise that sim ulated the activity patterns of a soccer m atch, using the activity pro W le described by Bangsbo et al. (1991). BrieX y, this activity pro W le categorizes the m ovem ent patterns of top professional players as follow s: standing, walking, low -intensity running, high-intensity running, and heading and tackling. For sim plicity, heading the ball, tackles and jum ping were not included in our protocol. F rom the percentage of total tim e and the m ean speeds for each activity, we calculated the approxim ate distance that should be covered for each activity. T hese distances were then divided by 42, since each activity was to be perform ed in 2 ´ 3 bouts of seven circuits. T he W ndings were then sim pliW ed to form a protocol of regular circuits that could be used in a W eld setting. For exam ple, according to Bangsbo et al. (1991), on average 16.7% (15 m in) of total tim e is spent jogg ing at a speed of 8 km ´ h - 1 (2.22 m ´ s - 1 ). This corresponds to a distance of 2.0 km and, therefore, a distance per circuit of 48 m . For sim plicity, the distance per circuit used in our protocol was 50 m . T he two 45 m in periods were separated by a 15 m in half-tim e inter val. Each 45 m in period was divided into three bouts of exercise. E ach bout was separated by 1.5 m in of rest, during w hich 150 m l of the prescribed drink was consum ed. T he bouts com prised seven circuits of 2 m in each: 50 m dribbling the ball through cones placed 5 m apart, 50 m backwards running, 25 m cruise running, 25 m m axim al sprint and 50 m walking (Fig. 1). Any rem aining tim e at the end of each 2 m in circuit was a rest period. A total distance of ~ 9.7 km was covered during the 90 m in exercise protocol; this is sim ilar to that reported to be covered during English First D ivision m atches by m id W eld players (Reilly and T hom as, 1976). Heart rates were recorded continuously during exercise using short-range radio telem etry (Sportstester PE3000, Polar Electro, Kem pele, Finland). Subjective ratings of perceived exertion (RPE) were obtained ever y

789


Immune responses to soccer-speciW c exercise

F igu re 1

Schematic illustration of the soccer-speciW c exercise protocol (adapted from Nicholas et al. , 1995).

15 m in using the revised scales of N oble et al. (1983). F urther blood sam ples were obtained at the half-tim e interval, at full-tim e and 1 h post-exercise. Saliva sam ples were also collected at these tim es. N o food was consum ed during this period and liquid ingestion was as prescribed. T he weather was dry and the tem perature was 20.5 ± 0.5 °C. B lood analyses Blood sam ples were collected into two separate vacutainer tubes (Becton D ickinson, U K), one containing

tripotassium ethylene diam ine tetraacetic acid (K 3 ED TA) and the other containing lithium heparin. Blood taken into K 3 ED TA vacutainers (4 m l) was used for haem atological analysis, including diV erential leucocyte counts using a Technicon H -2 laser system . Plasm a volum e changes were estim ated according to D ill and C ostill (1974). O f the 7 m l of blood dispensed into the lithium heparin vacutainers, 1.0 m l of the pre-exericse, im m ediately post-exercise and 1 h post-exercise sam ples was im m ediately added to separate snap-seal m icrocentrifuge (Eppendorf ) tubes containing 50 ml of bacterial lipopolysaccharide solution (Stim ulant, Sigm a, Poole,


790 UK ). Blood and lipopolysaccharide were m ixed by gentle inversion and then incubated for 1 h at 37 °C, and gently m ixed again after 30 m in. After incubation, the m ixture was centrifuged for 2 m in at 5000 g. T he supernatant was im m ediately stored at - 70 °C before analysis of elastase concentration. Plasm a elastase concentration was m easured using an E LISA kit (M erck, Lutterworth, UK ) and the am ount of elastase released from the stim ulated neutrophils was calculated as described by Blannin et al. (1997). For all sam ples, blood taken into lithium heparin vacutainers was spun at 1500 g for 10 m in in a refrigerated centrifuge to obtain plasm a, w hich was im m ediately stored at - 70 °C. After thaw ing, 100 ml aliquots of plasm a were deproteinized by m ixing w ith 1.0 m l of icecold perchloric acid (0.3 m m ol ´ l - 1 ). T he suspension was vortex-m ixed and then centrifuged for 1 m in at 5000 g. The supernatant was analysed for lactate using the m ethods described by F ink and C ostill (1995). Aliquots of plasm a were also analysed to determ ine the concentration of cortisol (EL ISA kit, Boehringer M annheim , Lewes, U K) and glucose (Hexokinase m ethod using N o. 16-50 kit, Sigm a, Poole, U K). Saliva collection and analysis

B ishop et al. analysis of variance w ith repeated m easures (2 ´ 3 for plasm a lactate and lipopolysaccharide-stim ulated elastase release per neutrophil and 2 ´ 6 for heart rate and RPE ). T he post-hoc Tukey test was used to assess any signiW cant diV erences. Certain sets of data were found to be skewed and, in these cases, statistical analysis was perform ed on the logarithm ic transform ation of the data. Statistical signi W cance was accepted at P < 0.05.

Results Changes in body mass and plasma volume Changes in body m ass, corrected for X uid intake, were sim ilar for both treatm ents (carbohydrate: 1.8 ± 0.2 kg; placebo: 1.5 ± 0.2 kg). There were no signiW cant interactions between treatm ent and tim e for changes in plasm a volum e. H owever, there was a signiW cant m ain eV ect of tim e, with the plasm a volum e at 45 m in of exercise and at the end of exercise being signiW cantly lower com pared with pre-exercise values (F 3,21 = 17.8, P < 0.01; Table 1). Heart rate and subjective ratings of perceived exertion du ring the soccer-speciW c exercise protocol

Each participant was asked to swallow to empty the m outh before the salivette swab (Sarstedt, N m brecht, Germ any) was placed under the tongue for 2 m in. All saliva swabs were then placed in their plastic containers and stored frozen at - 70 °C until analysis. After thawing, the swabs were spun at 5000 g for 5 m in at room tem perature and the volum e of saliva was recorded. From this, the saliva X ow rate ( ml ´ m in - 1 ) was determ ined by dividing the volum e of saliva by the collection tim e. Saliva volum e was estim ated by weighing to the nearest m illigram and saliva density was assum ed to be 1.00 g ´ m l - 1 (C ole and Eastoe, 1988). The concentration of im m unoglobulin A (IgA; m g ´ l- 1) in the saliva was determ ined by a sandwich-type ELISA m ethod (Blannin et al., 1998). Saliva IgA secretion rate ( mg ´ m in - 1 ) was then calculated from the saliva X ow rate and the concentration of IgA in the saliva. T he intra-assay coeY cient of variation of the m ethods based on analysis of 64 (48 for lactate) duplicate sam ples was 9.1%, 8.5% , 3.7% , 1.8% and 5.6% for IgA, glucose, lactate, cortisol and elastase, respectively. T he coeY cient of variation for the diV erential blood counts is