Exercise and energy

Elucidating the mechanisms of energy metabolism and its implications for exercise physiology is a classic subject of physiological research. The majority of the great minds in antiquity who wrote about physiology, medicine, and healthcare, did agree on the benefits of exercise for both a healthy body and a healthy mind. Around 400 BC, Hippocrates promoted exercise in moderation as a means to become and stay healthy.1 In ancient Persia, Avicenna's canon tried to explain the assumed mechanisms by which exercise was beneficial, and warns its followers not to overdo it.2 Exercise physiology can be considered an old and honorable subject.3 Given its long history, the sheer volume and quality of rather recent study results regarding exercise physiology and energy metabolism, which are continuously published in Acta Physiologica, is impressive. Research has recently focussed on, for example, the differential effects of exercise in subjects of different age groups4, 5 and the beneficial effects of endurance exercise on pathologies associated with an aging population, e.g. neuromuscular degenerative diseases6 and type 2 diabetes.7 Another societal challenge that exercises physiology—interestingly and successfully—addresses, is the health risks of children exposed to parental inactivity8 and metabolic disease.9 Interestingly, it is not always and only the mother who counts, and the potential preventive strategies resulting from these insights are of great value for the early prevention of metabolic disease.8 Another interesting publication has studied, in detail, the mechanism and energetic costs of rebuilding muscle following immobilization.10 Another concept that has only rather recently been investigated in relation to exercise is autophagy: The positive modulating effect of exercise on autophagy seems to mediate the cardiovascular protective mechanisms of exercise.11 Studies of athletic rather than regenerative or therapeutic exercise often focus on the ergogenic mechanisms that enable high performance. However, the interrelation of ergogenic mechanisms and pathophysiology have been investigated by,12 showing how the Na/K ATPase regulates metabolic reserve—and susceptibility to Western diet-related diseases.12, 13 Other interesting studies have focussed on the concepts of (a) fatigability14 and (b) muscle metabolism at rest and during different levels of use and stress, elucidating both the mechanisms of energy generation and consumption with regard to both physiological function and pathophysiology.15-17 Exerkines have been studied since IL-6 had originally been identified to be released systemically in response to exercise, however, have only recently emerged in all their relevance: they are defined as exercise-associated signaling molecules which act via endocrine, paracrine, and/or autocrine pathways, and may be involved in several of the systemic beneficial effects of exercise that have yet to be elucidated in full.18, 19 While most of the Northern Hemisphere feels asleep after the midwinter holidays and lots of good food, consider this a motivational aid to get back to the lab, the bench, and the running tracks, to investigate the full potential of this incredibly powerful, non-invasive lifestyle intervention, exercise. The authors declared no conflict of interest for this article.