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Clinical exercise tests are used primarily for diagnosis of coronary insufficiency or appraisal of working capacity. Occasionally hemodynamic responses are observed during diagnostic catherization of the heart. Since interpretation of findings depends upon quantitative differences from normal values, variations due to age, sex, physical status and circumstances of the test need to be appreciated. To be effective, exercise stresses must involve large muscle masses, and the patient or subject must be ambulatory, cooperative and properly motivated. Some of the approaches to testing will be reviewed, and preliminary observations on a new technique will be presented.The simplest test of exercise tolerance is for a physician to accompany a cardiac patient over one or more flights of stairs and to observe the symptoms. If this is not rewarding, increasing the work load by accelerating the pace or taking two steps at a time is more likely to be informative. But under these conditions the work loads are not well standardized, physiological responses are not usually monitored, and the physician is not necessarily of the same sex and comparable age.Master's two step test is familiar to most internists; its value for diagnosis and prognosis of coronary insufficiency has been established. 1,2 An abnormal resting electro-cardiogram is considered a contraindication for performance of this test. Although interpretation of results depends upon electrocardiographic changes, these have not been monitored routinely during exertion, even though a suitable technique was described 10 years ago. 3 The exercise stress varies with age, sex and body weight, but in terms of energy expenditure per unit of weight the underweight individual is stressed much more than the overweight person.

Krogh in 1912 (1) postulated the necessity for a large capacity venous reservoir capable of quickly delivering an autotransfusion of blood into the right heart during exercise, particularly in upright man, where Krogh felt venous return may at times be inadequate. Bock and co-workers (2) in their classical work reasoned that increased blood flow to working muscle, related in part to local vasodilation, must be partially effected by decreased splanchnic blood flow. Since the splanchnic region receives 20 to 25% of the total left ventricular output but extracts only 10 to 25% of the available oxygen (3), the splanchnic bed is ideally suited for rapid correction for any residual inbalance between left ventricular output and peripheral distribution of flow.The experimental evaluation of the influence of exercise on splanchnic blood flow, however, has produced conflicting results. Herrick, Grindlay, Baldes, and Mann (4), and more recently Rushmer, Franklin, Van Citters, and Smith (5) did not find a decrease in splanchnic blood flow in dogs undergoing an intensity of exercise far below their maximal capacities. Also plethysmographic studies in man by Sj6strand (6) led him to conclude that intrathoracic rather than splanchnic blood depots are functionally important in exercise.In contrast, a study by Bradley (7) and by Wade and co-workers (8)

The physiological benefit of the febrile response is poorly understood. Here we show that fever-range thermal stress enhances the function of the L-selectin lymphocyte homing receptor through an interleukin-6 (IL-6)-dependent signaling mechanism. Thermal stimulation of L-selectin adhesion in vitro and in vivo is mediated by engagement of the gp130 signal-transducing chain by IL-6 and a soluble form of the IL-6 receptor-alpha (sIL-6Ralpha) binding subunit. Thermal control of adhesion is maintained in IL-6-deficient mice through a gp130-dependent compensatory mechanism mediated by IL-6-related cytokines (i.e., oncostatin M [OSM], leukemia inhibitory factor [LIF], and IL-11). Combined biochemical and pharmacological inhibitor (PD98059, U0126, SB203580, SP600125) approaches positioned MEK1/ERK1-2, but not p38 MAPK or JNK, in the IL-6/sIL-6Ralpha signaling pathway upstream of activation of L-selectin/cytoskeletal interactions and L-selectin avidity/affinity. These results highlight a role for gp130-linked IL-6/sIL-6Ralpha transsignaling in amplifying lymphocyte trafficking during febrile inflammatory responses.

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The normal range of maximal values for oxygen consumption, heart rate, cardiac index, and stroke index during treadmill exercise testing are presented for 98 men and 104 women for ages 20-75 yr. These variables decrease with age in both sexes, but men show a significantly greater reduction than women with respect to oxygen consumption (P = 0.05), heart rate (P less than 0.02), and cardiac index (P less than 0.02). Comparison of the normal ranges of oxygen consumption, cardiac index, and stroke index indicated that men have significantly higher values than women (P less than 0.001). The normal range of heart rate was higher in younger men than women, but because of a more rapid decline with age in men, the older women had higher heart rates than the older men. Invasive measurements of cardiac index in 12 normal men and 11 normal women were within the defined normal range. These measurements showed that there was a greater increase in stroke index from supine rest to maximal upright exercise in men compared with the increase in women (means +/- SD, 12 +/- 9 m/m2 vs. 2 +/- 7 ml/m2, P less than 0.01).

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Surgical decompression of BRVO via A/V crossing sheathotomy is a technically feasible procedure that can result in rapid reperfusion of the retina. Resolution of macular hemorrhage, edema, and ischemia may improve visual prognosis in patients with this common retinal vascular disorder.