Background: Axial Spondyloarthritis (axSpA) is an autoimmune, chronic, rheumatic and inflammatory disease. In axSpA, the sacroiliac joint and the spine are affected, and common symptoms are stiffness and pain. For axSpA patients, systemic inflammation is a contributing factor to an increased risk of cardiovascular diseases (CVD). Calprotectin is a protein with multiple functions involved in the inflammatory response, and axSpA patients' calprotectin levels are elevated due to inflammation. Exercise is a non-pharmacological treatment, and for axSpA patients, it can reduce pain and increase mobility. The effects of High-intensity Interval Training (HIIT) have yet to be extensively researched in this patient group. Performing HIIT can increase maximal oxygen uptake (VO2max), reducing the risk of CVD. HIIT may also reduce inflammation, an essential factor in reducing the risk of CVD. Aim: The aim is to investigate how HIIT can affect calprotectin serum levels in axSpA patients and how calprotectin serum levels differ between healthy controls and axSpA patients. Method: Serum was collected before and after a HIIT bout from a cross-sectional pilot study, including axSpA patients (n=10) and healthy age- and sex-matched controls (n=11) and at baseline and after three months from a randomised control trial (RCT), which consisted of axSpA patients. The patients in the RCT were split into two groups: a control group (n=14) performing regular exercise and an intervention group (n=15) performing three HIIT sessions per week. Calprotectin in patients and healthy controls serum was analysed with a sandwich ELISA. Results: The comparison of serum calprotectin before and after a HIIT bout decreases in healthy controls (p=0.013) and indicates an increase of calprotectin in axSpA patients (p=0.059). After three months, the mean value of serum calprotectin in axSpA patients indicates a decrease in both the control and HIIT intervention groups. Conclusion: Our results suggest a trend towards regular HIIT, which can decrease serum calprotectin levels after three months. Therefore, HIIT could be considered a non-pharmacological treatment for axSpA patients. More studies with a larger axSpA population are necessary to investigate whether HIIT impacts serum calprotectin. / Bakgrund: Axial spondylartrit (axSpA) är en autoimmun, kronisk, reumatisk och inflammatorisk sjukdom. I axSpA påverkas sacroiliacaleden och ryggraden och vanliga symtom är stelhet och smärta. Patienter med axSpA har systemisk inflammation som är en bidragande faktor till ökad risk för hjärt-kärlsjukdomar (CVD). Kalprotektin är ett protein med flera funktioner som är involverat i den inflammatoriska responsen och hos patienter med axSpA är nivåerna av kalprotektin förhöjda på grund av inflammationen. Träning är en icke-farmakologisk behandling som kan minska smärta och öka rörlighet för axSpA patienter. Effekterna av högintensiv intervallträning (HIIT) har inte studerats i stor utsträckning i denna patientgrupp. Genom att utföra HIIT kan den maximala syreupptagningen (VO2max) förbättras, vilket kan minska risken för CVD. HIIT kan bidra till minskad inflammation, vilket kan minska risken för CVD. Syfte: Syftet är att undersöka hur HIIT kan påverka nivåerna av kalprotektin i serum hos patienter med axSpA och hur dessa nivåer skiljer sig mellan friska kontroller och patienter med axSpA. Metod: Serum har samlats in innan och efter ett HIIT pass från en tvärsnittsstudie och vid baseline och efter tre månader från en randomiserad kontrollstudie (RCT). Tvärsnittsstudien bestod av patienter med axSpA (n=10) samt friska ålders- och könsmatchade kontroller (n=11). RCTn bestod av patienter med axSpA som delades in i två grupper: en kontrollgrupp (n=14) som utförde regelbunden träning och en interventionsgrupp (n=15) som utförde tre HIIT-pass per vecka. Patienternas och de friska kontrollernas serum kalprotektin analyserades med en sandwich-ELISA. Resultat: Jämförandet av serum kalprotektin innan och efter ett HIIT pass hos friska kontroller visar en minskning av kalprotektin (p=0,013) och hos axSpA patienterna finns det en trend till en ökning av kalprotektin (p=0,059) efter HIIT-passet. Medelvärdet av serum kalprotektin hos axSpA patienter efter tre månader visar en tendens till en minskning i både kontroll- och HIIT-interventionsgruppen. Konklusion: Våra resultat indikerar att regelbunden HIIT efter tre månader kan minska nivåerna av serum kalprotektin. HIIT kan därför övervägas att vara en icke-farmakologisk behandling för axSpA patienter. Fler studier med en större axSpA population är nödvändigt för att vidare studera om HIIT påverkar serum kalprotektin.

Doctor of Philosophy / Department of Human Nutrition / Craig A. Harms / The overall aim of this dissertation was to ascertain the influences of lifestyle factors on airway health in children and young adults. In Study 1 (Chapter 2) the effect of a high-fat meal on airway inflammation and hyper-responsiveness was examined. Results revealed a post-prandial increase (p<0.05) in total cholesterol (~4%), triglycerides (~93%), and exhaled nitric oxide (a marker of airway inflammation, ~19%) two-hours following a high-fat meal (74.2±4.1g fat). These novel findings suggest that a high-fat meal may contribute to impaired airway function. In study 2 (Chapter 3) we assessed the role of body fat and physical activity (PA) on airway health in prepubescent children. This study revealed that children with higher-body-fat levels (>21%), who were not meeting current PA recommendations, experienced greater (p<0.05) amounts of post-exercise airway narrowing (FEV1, forced expiratory volume in 1-second, ~11%), as compared to children with lower-body-fat (<21%), who were meeting PA guidelines. These findings suggest that elevated adiposity and low PA levels may place children at risk for development of asthma and asthma-like symptoms. In study 3 (Chapter 4), based on study 2 results, we assessed the impact of 8 weeks of high-intensity interval training on airway health in children who were not meeting PA guidelines. We determined that high-intensity training significantly increased V02max (~24%), and decreased total cholesterol (~11%) and LDL cholesterol (~35%). Additionally, we found improvements (p<0.05) in ∆FEV1 both post-exercise (pre: -7.6±2.2%, post: -1.3±1.8%) and post-eucapnic voluntary hyperventilation (pre: -6.7±2.2%, post: -1.4±1.5%) with training. Further, Lower-body-fat and higher V02max subjects experienced significantly greater improvement in ∆FEV1 following training than higher-body-fat and lower V02max subjects (r=-0.80, r=0.73, respectively). These results suggest that in children, high-intensity training can ameliorate the negative health consequences of inactivity. However, increased body fat, and low V02max levels may constrain these improvements. This series of studies underscores the importance of dietary habits, body composition, and PA for airway health in children and young adults. These findings may be useful in determining policies and practices impacting children’s health, and could facilitate protocol development for prevention of asthma-like symptoms.

The following thesis investigates contemporary issues within the applied physiology of soccer refereeing. 1) Training performance. The impact of a high intensity training regime was examined in a group of elite-level soccer referees. Following a 16-month training period the referees’ performance on the YoYo Intermittent Recovery Test (level 1) improved by 46.5%. 2) Match Demands. The effect of match standard and referee experience upon the objective and subjective match loads of referees was investigated. Match heart rates (HR) and ratings of perceived exertion (RPE) were both related to standard of competition, with the match loads being higher on the higher standard of competition. Referee experience had no effect upon the referees’ match responses. Using a semi-automatic, video match analysis system the referees’ match activities and factors affecting these activities were also examined. Physical performances were related in part to the physical performances of the players; whilst the distances covered during the first half were related to second half coverage. 3) Ageing and performance. The effect of ageing upon referees’ fitness levels and physical match performances was addressed. Regression analysis revealed a trend towards an agerelated reduction in physical fitness, as determined by the referees’ fitness tests. Match activity analysis demonstrated a clear age-related decline in physical match performance, although this decline did not impair the referees’ ability to keep up with play. 4) Fitness and match performance. The validity of the FIFA referees’ fitness tests was examined. Interval test HR load was significantly correlated to the referees’ match coverage, both total distance and high intensity running. Sprint test scores also demonstrated a significant relationship with the referees’ match sprinting distances. However, given the strength of the relationships only the sprint test showed appropriate construct validity for the physical assessment of soccer referees.

Elevated postprandial triacylglycerol concentrations ([TAG]) are associated with the development and progression of atherosclerosis, and are established as an independent risk factor for future cardiovascular disease. Considering the majority of the daytime is spent in a postprandial state typically, and the paediatric origins of atherosclerosis are well established, lifestyle interventions including manipulations of exercise energy expenditure and dietary energy intake should be initiated early in life. Therefore, this thesis aimed to investigate the postprandial metabolic responses to different exercise and energy intake manipulations in boys and girls, with concentrations of circulating TAG representing the primary outcome of interest. To achieve this, a total of 60 healthy 11 to 13 year old boys and girls were recruited into five experimental studies. The first experimental study (Chapter 4) demonstrated that a single session of high-intensity interval running (HIIR) involving 10 x 1 min intervals at 100% maximal aerobic speed (MAS) resulted in a moderate reduction in postprandial plasma [TAG] in 11 to 12 year old boys. In the second experimental study (Chapter 5), immediate replacement of the moderate-intensity exercise-induced energy deficit negated the reduction in postprandial plasma [TAG] in 11 to 13 year old boys. Furthermore, an exercise-induced energy deficit was required to promote an increase in whole-body fat oxidation. The importance of the associated energy deficit was explored further in Chapter 6, which demonstrated that a moderate-intensity exercise-induced energy deficit elicited a greater reduction in postprandial plasma [TAG] than an isoenergetic diet-induced energy deficit in 11 to 13 year old girls (21% vs. 10% respectively). Chapter 7 compared the effect of 10 x 1 min interval runs at 100% MAS (HIIR) and 5 x 1 min interval runs at 100% MAS combined with a mild reduction in habitual energy intake by 0.82 MJ (195 kcal; HIIR-ER) on postprandial metabolism in 11 to 13 year old girls. Acute manipulations of low volume HIIR and ER reduced postprandial plasma [TAG] and increased resting whole-body fat oxidation, with the magnitude of effect marginally, although not meaningfully, greater following HIIR than HIIR-ER. The final experimental chapter (Chapter 8) compared directly healthy 11 to 13 year old boys and girls postprandial TAG responses to acute HIIR. Although postprandial plasma [TAG] was substantially lower in boys compared with girls, the magnitude of reduction following HIIR was similar between the sexes (11% vs. 10% respectively). Collectively, these studies demonstrate the efficacy of acute moderate- and high-intensity exercise, and to a lesser extent energy-intake restriction, to reduce postprandial plasma [TAG] and increase resting whole-body fat oxidation in boys and girls. Furthermore, the beneficial effect of exercise on postprandial metabolism appears dependent on the maintenance of the associated energy deficit. These lifestyle interventions have the potential to provide a practical, effective and engaging stimulus to promote a healthier cardiovascular risk profile in early adolescence.

High-intensity interval training (HIIT) consists of short intervals of exercise at high intensity intermitted by intervals of lower intensity and is associated with improvement of body composition and metabolic health in adults. Studies in overweight adolescents are scarce. We conducted a randomized controlled trial in overweight adolescents to compare acceptance and attendance of HIIT with or without weekly motivational encouragement through text messages and access to a study website. HIIT was offered for six months (including summer vacation) twice a week (60 min/session). Participation rates were continuously assessed and acceptance was measured. Clinical parameters were assessed at baseline and after six months. Twenty-eight adolescents participated in this study (age 15.5 +/- 1.4; 54% female). The standard deviation score for body mass index over all participants was 2.33 at baseline and decreased by 0.026 (95% CI - 0.048 to 0.10) units, p = 0.49. Waist to height ratio was 0.596 at baseline and decreased by 0.013 (95% CI 0.0025 to 0.024), p = 0.023. Participation within the first two months ranged from 65% to 75%, but fell to 15% within the last three months. Attendance in the intervention group was 14% (95% CI - 8 to 37), p = 0.18, higher than the control group. Overall program content was rated as \"good\" by participants, although high drop-out rates were observed. Summer months constitute a serious problem regarding attendance. The use of media support has to be assessed further in appropriately powered trials.

A associação de uma série de influências ambientais como dietas com excesso de gordura ou falta de atividade física regular (sedentarismo) são importantes fatores que podem levar ao desenvolvimento da obesidade e dislipidemias. Portanto, a prática de atividade física regular, caracterizada pelo treinamento, mostra-se atualmente como parte de estratégias para combater problemas como dislipidemias. Sabe-se que o aumento do gasto calórico e a melhora no desempenho podem ser atingidos com treinamentos de endurance ou intermitentes, uma vez que ambos levam à alterações fisiológicas e metabólicas semelhantes. O treinamento intermitente é caracterizado pela execução de repetidas sessões de curtos ou longos períodos, preferencialmente de alta intensidade (aproximadamente 100% do VO2máx.), intercaladas por pausas ou períodos de menor intensidade, visando a recuperação do indivíduo. Dada a importância do fígado no metabolismo lipídico em repouso e no exercício foi nosso interesse avaliarmos o comportamento do fígado frente a oito semanas de treinamento intermitente de alta intensidade e comparar tais alterações às promovidas pelo treinamento de endurance em ratos, com especial atenção a síntese e secreção de VLDL. Os animais foram divididos em três grupos: sedentário (SD), treinamento contínuo (TC) e treinamento intermitente de alta intensidade (TI). Os dois protocolos de treinamento resultaram em menor ganho de peso em comparação com o grupo SD. Ainda o grupo TI apresentou maior secreção de VLDL em comparação aos grupos TC e SD. Além disso, a expressão gênica da MTP, proteína chave na montagem da VLDL e da LPL muscular responsável por catalisar a liberação de TAG da VLDL para captação pelo músculo esquelético demonstrou aumento no grupo TI em comparação ao SD. Tais resultados inferem que o treinamento intermitente modulou o transporte de TAG para a periferia e contribui para um efeito hipotrigliceridêmico após o exercício de alta intensidade / The combination of environmental influence, including high fat diets and lack of regular physical activity (sedentary lifestyle) are important factors leading to the development of obesity and dyslipidemias. Regular practice of physical activity, characterized by training, appears as important strategy to reduce such problems. Increased caloric expenditure and improvement of physical performance can be reached with endurance or intermittent training since both lead to similar physiological and metabolic adaptations. Intermittent training is characterized by the execution of repeated bouts of physical effort (high intensity, approximately 100% of VO2max.) Due to the importance of the liver in lipid metabolism during rest and exercise, we examined the adaptations of organ to 8 weeks of high intensity intermittent training, compared with the effect of endurance exercise with special attention to VLDL synthesis and secretion. The animals were randomized into three groups: sedentary (SD), continuous training (TC) and intermittent training (TI). Both training protocols resulted in reduced weight body gain compared with SD, although IT presents higher VLDL secretion, compared with TC and SD. In addition, gene expression of MTP, a key protein in the assembly of VLDL and LPL muscle responsible for catalyzing the release of TAG for VLDL uptake by skeletal muscle, showed an increase in TI compared to SD. These results suggest that intermittent training modulated the transport of TAG to the periphery and contributed to an hypotriglyceridemic effect caused by high intensity exercise

A manutenção da saúde, depende, dentre outros aspectos, do controle da massa corporal, uma vez que a obesidade está associada ao desenvolvimento de doenças crônicas. Sendo assim, o exercício pode ser considerado uma ferramenta eficaz nesse controle. Contudo, está evidenciado que o exercício realizado em alta intensidade pode ocasionar maior redução da gordura corporal. Dentre as hipóteses sugeridas para explicar tal fenômeno, a supressão do apetite pós-exercício foi levantada, no entanto, o efeito da intensidade sobre o apetite ainda é incipiente. Além disso, mulheres podem ter maior resposta compensatória que homens. Portanto, o objetivo do estudo foi comparar o efeito da intensidade no controle agudo do apetite, energia ingerida absoluta e relativa (energia ingerida menos o gasto calórico do exercício), percepção de fome e das concentrações sanguíneas de grelina acilada, peptídeo YY3-36, insulina, cortisol, glicose, ácidos graxos, colesterol e triacilglicerol em homens e mulheres. Para isso, 11 homens e 9 mulheres eutróficos, foram submetidos a 6 sessões, sendo a primeira destinada à determinação da potência aeróbia máxima (PAM) em cicloergômetro, e a segunda para realização do exercício intermitente de alta intensidade realizado na máxima intensidade (all out), composto por 60 x 8s:12s (EIAI-A), para determinação do trabalho total, o qual foi utilizado para equalização das demais sessões: a) EIAI-A; b) exercício intermitente de alta intensidade (EIAI) - 60s:60s a 100% da PAM; c) exercício contínuo de intensidade moderada (ECMI) a 60% da PAM; d) sessão controle (sem exercício). Cada visita teve duração de 4h, sendo que os participantes chegaram em jejum e receberam um café da manhã padrão. O exercício foi realizado 1,5h pós-café da manhã, e uma alimentação ad libitum foi servida 4h pós-café da manhã. Coletas de sangue e da percepção de fome (escala analógica visual) foram realizadas em jejum e em 2, 2,5, 3,25 e 4h de experimento e calculada a área sob a curva (ASC) para cada uma dessas variáveis. A comparação das variáveis sanguíneas e da percepção de fome foi feita através de análise de variância a três fatores (condição, sexo e momento), e das variáveis envolvendo a ASC e a energia ingerida foi conduzida através de análise a dois fatores (condição e sexo), seguida do pós-teste de Bonferroni se observada diferença significativa (P<0,05). Não houve diferença para a energia ingerida absoluta, porém, a energia ingerida relativa foi maior no controle quando comparada ao EIAI-A, EIAI, e ao ECMI, sem diferenças entre os tipos de exercício e sexos. A ASC da percepção de fome foi menor somente nos exercícios realizados em alta intensidade comparado com o controle, independentemente do sexo. O PYY3-36 foi inferior nas mulheres em relação aos homens ao passo que o cortisol foi inferior nos homens comparado com as mulheres. Houve interação entre situação e momento de coleta para o cortisol e insulina sendo os valores mais elevados no EIAI-A que no controle às 2,5 horas de experimento para o cortisol e às 3,25h para insulina. Portanto, embora não tenha havido diferença na energia ingerida relativa entre os tipos de exercícios, àqueles realizados em maior intensidade foram capazes de promover efeitos mais pronunciados na supressão do apetite, independentemente do sexo / Maintaining one\'s health depends, among other things, on controlling body weight, since obesity is associated with the development of chronic diseases. Accordingly, exercise is an effective tool in this control. It has been demonstrated that exercise performed at a high intensity can cause greater reduction in body fat. Among the hypotheses put forward of this phenomenon is the suppression of appetite. However, the understanding of the effect of the intensity on appetite is still incipient. In addition, women may have a greater compensatory response than men. Therefore, the aim of the study was to compare the effect of intensity on absolute and relative (energy intake less caloric expenditure of the exercise) energy intake, hunger and blood concentrations of acylated ghrelin, PYY3-36, insulin, cortisol, glucose, fatty acids, cholesterol and triacylglycerol in men and women. Accordingly, 11 men and 9 women, all eutrophic, underwent six sessions. The first was designed to determine their maximum aerobic power (MAP) on a cycle ergometer, and the second involved performing high-intensity intermittent exercise at maximum intensity (all out) for 60 x 8s: 12s (HIIE-A) in order to determine the total work, which was used for the equalization of the other sessions: a) HIIE-A; b) high intensity intermittent exercise (HIIE) - 60s: 60s at 100% of MAP; c) steady-state exercise (SSE) at 60% of the MAP; d) a control session. Each session lasted a total of 4 hours. The participants arrived in fasting and received a standard breakfast upon arrival. The exercise session was performed 1.5 h after breakfast, and an ad libitum meal was served 4 hours post-breakfast. Blood sample collection and perception of hunger were collected when fasting and at 2, 2.5, 3.25 and 4 hours into the experiment and the area under the curve (AUC) for each of these variables was calculated. A comparison of the blood sample variables and rating of hunger was performed by analyzing the variance of three factors (condition, sex, and time) and the analysis of the variables involving the AUC and energy intake was conducted through examination of two factors (sex and condition) followed by a Bonferroni post-test if significant differences (P<0.05) were observed. There was no difference for the absolute energy intake, however, relative energy intake was higher in the control compared to HIIE-A, HIIE, and SSE, with no differences between the types of exercise and sex. The AUC of hunger was lower in exercises performed at high intensity when compared to the control, regardless of sex. There was interaction between condition and time for cortisol and insulin, with higher levels in the HIIE-A than in the control at 2.5 hours for cortisol and 3.25 hours for insulin. Therefore, although there were no differences in energy intake relative to the types of exercises, those performed at a higher intensity promoted more pronounced effects on appetite suppression, regardless of sex

Embora os cavalos apresentem características excepcionais frente a situações de estresse na natureza, foi considerada a possibilidade do cavalo de corrida ser submetido, por vezes, a alguma situação de estresse, que afetasse sua saúde e bem estar. Foram verificadas alterações do número e da função de populações celulares implicadas com a defesa, principalmente neutrófilos e linfócitos. Trinta cavalos de corrida da raça puro-sangue inglês, locados no Jockey Club de São Paulo, na cidade de São Paulo, foram utilizados. Os animais foram divididos em dois grupos e as amostras de sangue foram coletadas em momentos diferentes da rotina dos animais. No grupo I, foram coletadas amostras onze dias antes da corrida (-11d), imediatamente após a corrida (0d), um dia após a corrida (+1d), dois dias após a corrida (+2d) e três dias após a corrida (+3d). Enquanto, no grupo II as amostras foram coletadas oito dias antes da corrida (-8d), imediatamente após a corrida (0d), um dia após a corrida (+1d) e cinco dias após a corrida (+5d). Foram realizados ensaios de fagocitose e burst oxidativo dos neutrófilos, determinação de cortisol sérico, ensaios de apoptose, linfoproliferação e hemograma. A função de fagocitose, tanto em porcentagem, quanto em intensidade, mostrou-se diminuída nas amostras coletadas imediatamente após a corrida, nos dois grupos de animais. Os valores médios de burst oxidativo das amostras coletadas imediatamente após a corrida, dos animais do grupo I apresentaram-se diminuídos. Não foram encontradas diferenças estatísticas significantes entre os resultados obtidos em relação às células apoptóticas, quando os diferentes momentos foram comparados; o mesmo ocorreu quando foi realizado o confronto dos valores do ensaio de linfoproliferação. Os valores médios dos níveis séricos de cortisol apresentaram-se aumentados no momento imediatamente após a corrida, em relação aos valores dos outros momentos, nos dois grupos de animais. Quanto aos dados de hemograma, houve aumento do número percentual de neutrófilos no momento imediatamente após a corrida quando foi realizada comparação com os demais momentos. Nos cavalos estudados, ainda que tenha sido encontrada uma diminuição transitória na função dos neutrófilos, a função adaptativa não chegou a ser acometida, que sugere que, embora se constitua em um exercício de alta intensidade, a fugacidade da corrida acabe por evitar danos maiores, em animais bem condicionados e adaptados a situações de estresse / Although horses can present exceptional responses during stress situations in nature, it was raised the possibility that racehorses under certain stress conditions could develop changes that may affect their health and welfare. Alterations of the number and function of cells that are involved with the defense response, mainly neutrophils and lymphocytes populations were verified. Thirty Thoroughbred racehorses housed at the Jockey Club de São Paulo, in São Paulo, Brazil, were used in the present study. The animals were divided in two groups and blood samples were collected at different moments of their routine. In group I, the samples were collected eleven days before race (-11d), immediately after race (0d), one day (+1d), two days (+2d) and three days after race (+3d). In group II, the samples were collected eight days before race (-8d), immediately after race (0d), one day (+1d) and five days after race (+5d). Phagocytosis assay and oxidative burst activity of neutrophils, serum cortisol determination, apoptosis and lymphocyte proliferation assay and haematology tests were performed. The percentage and intensity of phagocytosis functions decreased in samples collected immediately after race, in both groups of animals. The mean values of oxidative burst activity of samples collected immediately after race, from animals of group I also decreased. Statistically significant differences between the results were obtained in relation to the apoptotic cells, when compared on different moments and the same occurred in Relation to the lymphocyte proliferation values. The mean values of serum cortisol levels increased at the moment immediately after race when compared with the values of the other moments, in both groups of animals. In relation to the haematologycal values, the percentage of neutrophils was increased at the moment immediately after race when compared with the other moments. Even though a transitory reduction in the neutrophils function has occurred, the adaptive function was not impaired, which suggest that, in spite of the high intensity of this exercise, the short-term race can prevent further damages in well-conditioned and stress-adapted animals

Recent years have witnessed significant research into the acute effects of exercise on appetite, energy intake and gut hormone responses. The experiments in this thesis have further investigated this topic by examining the appetite, acylated ghrelin, peptide YY and energy intake responses to energy deficits induced via different exercise protocols and food restriction. To achieve this, 48 young healthy males (mean (SD): age 23 (3) years, body mass index 23.7 (2.7) kg.m-2, maximum oxygen uptake 52.9 (9.8) mL.kg 1.min-1) were recruited into four studies. In study one, 60 min of treadmill running at 70% of VO2 max did not stimulate any increases in appetite or daily energy intake regardless of whether the exercise was performed after breakfast or in the fasted state. In study two, six 30 s Wingate tests stimulated increases in appetite during the subsequent hours compared with 60 min of cycling at 68% of VO2 max. Differences in appetite appeared to be unrelated to changes in plasma acylated ghrelin concentrations and did not influence ad libitum energy intake. Subsequently, endurance exercise resulted in a significantly greater negative daily energy balance than sprint exercise due to a larger exercise energy expenditure. Study three revealed that appetite and energy intake did not differ from a resting control trial after either ten, 4 min cycling bouts at 85 90% of VO2 max separated by 2 min of rest or 60 min of constant cycling at 60% of VO2 max. This occurred despite elevated PYY3-36 concentrations during the hours after exercise. Finally, study four showed that an energy deficit of ~1475 kJ stimulated increases in appetite when induced via food restriction but not when achieved by an acute bout of exercise. This was associated with differences in plasma PYY3-36 concentrations but did not appear to be related to changes in circulating levels of acylated ghrelin and did not influence energy intake. This thesis has shown that appetite perceptions do not differ from a resting control trial during the hours after continuous endurance exercise. Alternatively, supramaximal cycling exercise and subtle reductions in food intake stimulated increases in appetite during the subsequent hours. Such increases in appetite do not appear to be related to changes in acylated ghrelin but may be influenced by plasma PYY3-36 concentrations. Despite differences in appetite, daily energy intake was unaffected by all interventions.

No description available.