at various stages of magnesium repletion of the patient represented in fig3 a 3c in calcium deficiency the rise time is prolonged and heat production continues to exceed the cooling efficiency of the circulation for some seconds after the muscle movement ceases the base line is very stable and there is a marked increase in stable heat see fig5 a and 5b iron deficiency has a marked effect on the test in children the stable heat is absent which presumably reflects changes in the cytochrome cascade which is iron dependent the effect is not nearly so marked in iron deficient adults fig6 shows the pattern obtained from an iron deficient 7 year old girl who had reduced serum iron and ferritin levels and an increased transferrin level in four teenaged patients without vascular problems or magnesium deficiency the widening of the contraction peak that is seen in reduced oxygenation or perfusion was found these patients had low serum manganese levels all four were given manganese supplements in all cases the test results normalised within four weeks and three of the four had complete correction of the clinical muscle problem the fourth had only about 50 improvement patients taking lithium compounds have decreased resting heat and stable heat there is also a tendency towards base line drift some organic drugs including barbiturates have effects on the recovery heat and the relaxation heat decreased resting heat stable heat recovery heat and relaxation heat are seen in hypothyroidism this is shown in fig7 hyperthyroidism and pyrexia lead so similar changes in the test results as shown in fig8 and 9 in folate deficiency the changes seen include an erratic contraction peak as demonstrated in fig1 in lacticacidosis the changes are those that have.