Muscle Action, Trace Elements and Related Nutrients: The Myothermogram

Howard J In: Chazot G, Abdulla M, Arnaud P, eds. Current Trends in Trace Element Research: Proceedings of International Symposium on Trace Elements. Paris, 1987, Smith-Gordon, London, 1989, pp79-85 Introduction In the investigation of muscle problems it is relatively easy to measure the circulating levels of nutrients known to be involved in muscle function. Such data frequently fail to provide enough information about metabolic problems within the muscle. In diagnosis and in following the treatment of muscle-related problems a functional test is needed. In the subcellular events responsible for muscle contraction the biochemical energy utilized must equal the energy output of the system and this is essentially the external work done plus the heat energy produced. The external work can be limited so that a plot of the heat produced during contraction and relaxation should reflect the subcellular chemistry. The limiting factors are the difficulty of detecting very small temperature changes and the efficient way in which muscle heat is conducted away by the circulation. The use of sensitive temperature recording equipment in a clinical test of muscle action is described. Abnormalities of potential diagnostic significance are demonstrated in deficiencies of magnesium, calcium, iron (in children), manganese and folate. The test also detects reduced oxygenation or perfusion and abnormal results are seen in thyroid disorders. It will be shown that muscle damage can result from exercise during magnesium deficiency.