In recent years there has been a surge in interest concerning high intensity intermittent exercise training (HIT) due to its ability to confer rapid notable cardio-metabolic health benefits. Specifically, HIT has been shown to improve insulin sensitivity and glycaemic control as well as other cardiovascular health factors after just 2 weeks of training (typically 6 training sessions). This thesis investigated the potential therapeutic role of HIT training within obese cohorts specifically addressing metabolic health, inclusive of inflammatory profiles and glycaemic control.

The IL-6 system is key in the development of chronic low-grade inflammation. It is known to be upregulated in response to acute exercise and lowered at rest after exercise training. IL-6 has both anti- and pro-inflammatory properties and moderation of this cytokine could alleviate chronic low-grade inflammation which is associated with obesity and Type 2 diabetes mellitus (T2DM). This thesis investigated the interplay between inflammation, glycaemic control and high intensity intermittent training (HIIT) - an exercise regimen that has been shown to yield many health benefits. There was a greater increase in IL-6 after an acute bout of HIIT than continuous moderate intensity exercise, where external work was matched (Chapter 4). Although sIL-6R and the IL-6/sIL-6R complex were both significantly increased after acute exercise there were no differences between HIIT and moderate intensity exercise. In response to 2 weeks HIIT there was a significant reduction in IL-6 and increase in IL-6R in adipose tissue in overweight and obese males (Chapter 5). It was also determined that IL-6R present in adipose tissue is at least partly composed of the membrane-bound IL-6R isoform (Chapter 6). Reductions in circulating sIL-6R, the IL-6/sIL-6R complex, MCP-1 and adiponectin, as well as a decrease in waist circumference and increase in peak oxygen uptake during exercise were also induced after 2 weeks HIIT (Chapter 5). Young adults with T2DM (< 40 y) displayed elevated levels of inflammatory proteins in comparison to lean controls, however there were no significant differences in comparison to obese controls (Chapter 7). In conclusion, the findings of this thesis demonstrate that acute and repeated bouts of HIIT have positive effects on the inflammatory profile in the circulation and adipose tissue, particularly in relation to the IL-6 system. It should be determined if HIIT is an achievable mode of exercise for patient populations, including T2DM patients, in order to downregulate the inflammatory profile.

Submitted by FLAVIANE POLETO DE OLIVEIRA null (fla_vb13@hotmail.com) on 2018-03-24T13:04:27Z No. of bitstreams: 1 Dissertação de mestrado_Flaviane Poleto_versão definitiva.pdf: 677650 bytes, checksum: b1dd23673956cadc620d339f8764038f (MD5) / Approved for entry into archive by Claudia Adriana Spindola null (claudia@fct.unesp.br) on 2018-03-26T12:39:15Z (GMT) No. of bitstreams: 1 oliveira_fp_me_prud.pdf: 677650 bytes, checksum: b1dd23673956cadc620d339f8764038f (MD5) / Made available in DSpace on 2018-03-26T12:39:15Z (GMT). No. of bitstreams: 1 oliveira_fp_me_prud.pdf: 677650 bytes, checksum: b1dd23673956cadc620d339f8764038f (MD5) Previous issue date: 2018-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O Treinamento Concorrente (a combinação de exercício aeróbio com treinamento de força) pode resultar em uma interferência negativa no desempenho de força. Além disso, há indicações de que a magnitude dessa interferência é dependente do modo/intensidade do exercício aeróbio. OBJETIVO: Sendo assim, o objetivo deste estudo foi comparar o efeito agudo do Treinamento de Força (TF) e do Treinamento Concorrente (TC) consistidos do Treinamento Intermitente de Alta Intensidade (HIIT) sob os ganhos de força máxima e volume durante 12 semanas. MÉTODOS: A amostra foi composta por 19 homens recreativamente ativos divididos entre o grupo TC (n=11) e grupo TF (n=8). O grupo TC realizou o HIIT (1min de corrida a 100% da velocidade aeróbia máxima intercalado por 1min de recuperação passiva até atingir 5 km) e em seguida uma sessão de treinamento de força constituída por oito exercícios com cargas de 8-12 repetições máximas, enquanto o grupo TF realizou apenas as sessões de treinamento de força. Ambos os grupos treinavam duas vezes por semana durante 12 semanas. A força máxima e o volume de treinamento durante uma sessão aguda foram avaliados pré, após oito e 12 semanas de treinamento. RESULTADOS: Um pequeno efeito de interferência foi observado na força máxima em relação à massa corporal após 12 semanas de treinamento com maiores melhorias no grupo TF quando comparado ao grupo TC. A mesma não foi observada após oito semanas de treinamento. CONCLUSÃO: Esses resultados sugerem que o volume realizado não exerceu impacto nos ganhos de força até oito semanas de treinamento concorrente constituído por HIIT. / The concurrent training (i.e., combination of endurance with strength training) may result in negative interference on strength performance. Moreover, there are indications that the magnitude of this interference is dependent on endurance exercise mode. PURPOSE: The purpose of this study was to compare maximal strength gains and acute volume performed during strength training (ST) and concurrent training (CT) consisting of high-intensity intermittent training plus strength training over the course of a 12-week intervention. METHODS: Nineteen recreationally active males were divided in CT (n=11) and ST (n=8) groups. The CT group performed repeated 1 min efforts at 100% of maximal aerobic velocity interspersed by 1 min of passive recovery until accumulating a total running distance of 5km followed by a strength session (consisting of three sets of eight exercises with loads of 8-12 repetition maximum) twice weekly for a period of 12 weeks, while the ST group performed only strength training sessions. Maximal strength and training volume during an acute exercise session were evaluated at baseline and after eight and 12 weeks of training. A two-way analysis of variance (group and training period) with repeated measures in the second factor was conducted to compare maximal strength values. A three-way analysis of variance (group, training period and set) was conducted to compare the volume performed in the acute exercise sessions. RESULTS: A small interference effect was observed in maximal strength relative to body mass after 12 weeks of training with greater improvements in the ST group compared to the CT group, that were not observed after 8 weeks. The volume performed during the acute exercise session was lower in CT than ST after 8 and 12 weeks of training. In summary, executing high-intensity intermittent exercise before strength training impaired the total volume performed after 8 and 12 weeks compared with strength training alone but the impairment of maximal strength occurred only after 12 weeks. CONCLUSION: These results suggest that the impairment of volume performed did not have an impact on strength gains until after 8 weeks of concurrent training with high-intensity intermittent exercise.