Effect of exercise on erythrocyte count and blood activity concentration after technetium-99m in vivo red blood cell labeling.

Abstract

SUMMARY We studied the effect of exercise on blood radiotracer concentration after technetium-99m in vivo red blood cell labeling. After red blood cell labeling, 13 subjects underwent maximal supine bicycle exercise. Radioactivity, analyzed with a well counter, was measured in heparinized venous blood samples drawn at rest and during peak exercise. Changes in activity were compared with changes in erythrocyte count. Activity and erythrocyte counts increased during exercise in all 13 subjects. Percent increase in activity correlated with percent increase in erythrocyte count (r = 0.78), but did not correlate with either duration of exercise or maximal heart rate. Twenty minutes after termination of exercise, activity and zrythrocyte count had decreased from peak exercise values but remained higher than preexercise values. In iiine nonexercised control subjects, samples drawn 20 minutes apart showed no change in activity or in erythrocyte count. We conclude that exercise increases blood activity, primarily because of an increase in erythrocyte count. During radionuclide ventriculography, blood activity must be measured before and after any intervention, particularly exercise, before a change in left ventricular activity can be attributed to a change in left ventricular volume.EQUILIBRIUM radionuclide ventriculography is a useful method of estimating left ventricular volume and output. '4 After blood pool labeling, which may be achieved by erythrocyte tagging with technetium-99m (9 mTc),. "the ratio of left ventricular activity to peripheral blood activity concentration is proportional to left ventricular volume. The effect of exercise on left ventricular volumes has been examined by observing the changes in left ventricular counts.7-9 As long as the radiotracer remains in constant concentration within the circulation during exercise, no measurement of blood activity is needed to assess the percent change in left ventricular volume. Furthermore, using a single determination of blood activity, absolute ventricular volumes can be determined at rest and during exercise. However, if blood activity changes during exercise, the magnitude of the change must be known before alterations in ventricular volumes can be determined based on changes in ventricular activity.Studies in animals'0 "I and in man'1 have demonstrated an increase in hemoglobin concentration during exercise. We studied the effect of exercise on blood activity concentration after 99mTc in vivo red blood cell labeling, and compared changes in blood activity with changes in erythrocyte count. MethodsThe study population consisted of 22 subjects who had been referred for radionuclide ventriculography. Red of these patients, blood samples were also drawn 20 minutes after termination of exercise. In nine nonexercised controls, blood samples were drawn 10 and 30 minutes after pertechnetate injection. Each 10-ml venous blood sample was drawn through a separate venipuncture in the arm not used for pertechnetate injection and was injected into an evacuated hepari...

Association of physical activity and sedentary time with blood cell counts: National Health and Nutrition Survey 2003-2006

“…Conflicting results in the literature have shown MVPA may decrease [ 33 , 34 ] or increase levels of RBCs [ 35 ]. While we observed a borderline significant linear trend in RBCs with greater MVPA using model 1, the trend was not observed after including additional covariates in model 2, suggesting potential confounding by health status or other factors.…”

Contrasting response of haematological variables between long-term training and short exercise bouts in zebra finches (Taeniopygia guttata)

“…Regular training of different modes and intensity frequently leads to decreases in haematological variables, particularly Hct and Hb content, compared with pre-training values or those in untrained individuals (Puhl and Runyan, 1980;Dressendorfer et al, 1981;Green et al, 1991). By contrast, elevation of Hct, Hb content and/or RBC count occurs as an immediate response to a single and intensive exercise bout (Novosadová, 1977;Konstam et al, 1982;Ernst et al, 1991). This latter pattern is often found in other mammal groups, in particular in dogs and horses, which have been extensively studied in terms of cardiovascular adaptations to physical activity.…”

Physical Activity Increases the Total Number of Bone-Marrow-Derived Mesenchymal Stem Cells, Enhances Their Osteogenic Potential, and Inhibits Their Adipogenic Properties

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