 Over the last decades, the number of obese people has more than quadrupled. Nowadays, more than 200 million men and 350 million women in the world are obese. And the increase in obesity prevalence does not seem to slow down to date. Obesity is associated with severe medical consequences. It predisposes to non-communicable diseases such as type 2 diabetes, cardiovascular disease, as well as cancer. And the impact of those comorbidities on our healthcare systems, as well as on our societies, is enormous. As a scientist and passionate sportswoman, I've always found these data very intriguing, because the best treatment for obesity and its related disorder has been known since many years. Whether it's running or cycling or just taking the stairs instead of the elevators, any type of exercise protects against disease and promotes health. The concept that exercise is medicine has been put forward some years ago. Yet, while a lot of effort is put on trying to understand specific disease mechanisms, we still do not understand how exercise promotes health. In other words, how muscle contraction can start up a cascade of events that ultimately lead to health is poorly understood. And what I would like to propose here is to use exercise as a model to study health. Would it not be better to prevent disease rather than treating it? Or what can we learn from studying health? And perhaps instead of restricting our research focus only on searching for novel or understanding disease mechanisms, perhaps we can find novel therapies to fight disease by understanding how exercise promotes health. But this might be more difficult than initially anticipated, because exercise does not only increase health inside the active muscles. No, the muscle also secretes factors that circulate through the body and might have impact on other organs. Exercise makes you healthy, but also happy and smart. Moreover, the muscle is not, while much research has been focusing on the muscle fiber itself, the muscle in fact contains many other cell types, which all together form the so-called muscle microenvironment. During exercise, those cell types closely interact and they coordinate adaptations to training. And one particularly interesting is the role of the blood vessels. Blood vessels deliver oxygen and nutrients, but also remove waste products. And at the same time, they provide the niche where other cell types, including muscle stem cells, like to reside. Now, one of the very early adaptations to exercise is the expansion of the vascular network. My lab studies how blood vessels grow inside the muscle and how blood vessels interact with other cell types within this muscle microenvironment. And we study in great detail how blood vessels grow inside the muscle. In fact, the activation of one single vascular cell can initiate the formation of a completely new blood vessel where every cell instructs its neighboring cell to take up a specific and specialized role. But the muscle has also developed a distinct way to increase its vascular bed. The coordinated growth of vascular cells can lead to the splitting of the vessel and the formation of a parallel vascular structure. Whenever those blood vessels grow, we think that this, the increase in blood vessel growth instructs other cells to also reshape and optimize the muscle microenvironment. In fact, we believe that those newly growing blood vessels can actually sense the nutrient requirements of the adjacent muscle fibers and can adapt themselves to promote optimal oxygen and nutrient delivery to the fiber. We hypothesize that the increase in vascular growth in the muscle therefore leads to a complete reshaping of the muscle microenvironment, which ensures long-term training adaptations but also provides a platform for the delivery of health-promoting effects through the rest of the body. By understanding the key steps that control vascular growth in the muscle and the molecular mechanisms underlying the communication between the muscle fibers and its microenvironment, we think that we can discover innovative and unexplored therapies for the treatment of disease and the promotion of health. Thank you.