Retention of blood oxygen and loss of tissue Mg is proportional to sympathetic activity – practical consequences

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Abstract

Abstract. To investigate the impact of mental excitement on metabolism we collected pH, pCO 2 , pO 2 , and ionized Mg values out of capillary blood of 192 cadets, won during the expectation phase before a running trial, important for their military officer career. Mostly by linear correlation analyses, we could show that probable higher catecholamine levels, not uncommon in sympatho-adrenal anticipation, seem to ultimately provoke increased oxygen binding in blood as well as (temporary) Mg increase in blood as a consequence of Mg loss from tissues. Both processes, O 2 retention in blood and Mg loss from tissues contribute to impaired workload resistance of the metabolism. 

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Influence of magnesium status and magnesium intake on the blood glucose control in patients with type 2 diabetes.

Cristiane Hermes Sales, Lucia Fatima Campos Pedrosa, Josivan Lima … (2011)

This study was undertaken to assess magnesium intake and magnesium status in patients with type 2 diabetes, and to identify the parameters that best predict alterations in fasting glucose and plasma magnesium. A cross-sectional study was carried out in patients with type 2 diabetes (n = 51; 53.6 ± 10.5 y) selected within the inclusion factors, at the University Hospital Onofre Lopes. Magnesium intake was assessed by three 24-h recalls. Urine, plasma and erythrocytes magnesium, fasting and 2-h postprandial glucose, HbA1, microalbuminuria, proteinuria, and serum and urine creatinine were measured. Mean magnesium intake (9.37 ± 1.76 mmol/d), urine magnesium (2.80 ± 1.51 mmol/d), plasma magnesium (0.71 ± 0.08 mmol/L) and erythrocyte magnesium (1.92 ± 0.23 mmol/L) levels were low. Seventy-seven percent of participants presented one or more magnesium status parameters below the cut-off points of 3.00 mmol/L for urine, 0.75 mmol/L for plasma and 1.65 mmol/L for erythrocytes. Subjects presented poor blood glucose control with fasting glucose of 8.1 ± 3.7 mmol/L, 2-h postprandial glucose of 11.1 ± 5.1 mmol/L, and HbA1 of 11.4 ± 3.0%. The parameters that influenced fasting glucose were urine, plasma and dietary magnesium, while plasma magnesium was influenced by creatinine clearance. Magnesium status was influenced by kidney depuration and was altered in patients with type 2 diabetes, and magnesium showed to play an important role in blood glucose control. Copyright © 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

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Stress and acid-base balance in chickens.

H.A. Olanrewaju, S Wongpichet, J.P. Thaxton … (2006)

Two trials were conducted to study the effects of continuous infusion of adrenocorticotropic hormone (ACTH) on acid-base balance in broiler chickens. Osmotic pumps delivered 8 IU of ACTH in saline/kg of BW/d for 7 d or the same saline volume as used in ACTH at 1 microL/h for 7 d. Blood samples were taken on d 0 (baseline values) and on d 4, 7, and 14 after onset of the infusions. The ACTH treatment increased the hematocrit, partial pressure of CO2, anion gap, corticosterone, mean corpuscular hemoglobin concentration, the blood concentrations of hemoglobin and HCO3-, and reduced the partial pressure of O2, plasma concentrations of Na+, K+, and Cl-. Blood pH values and plasma concentrations of Ca2+ were unaffected by ACTH treatment. The ACTH infusion also resulted in a significant increase in plasma glucose, cholesterone, high-density lipoprotein, and triglyceride. There were no differences in any of the blood constituents measured from control groups. Results indicate that infusion of ACTH resulted in changes in plasma acid-base status along with changes in other blood metabolic variables. However, the ACTH treatment did not prevent homeostatic regulation of acid-base balance, as indicated by constant blood pH. There was, however, an increased need for O2 to support gluconeogenic energy production; the birds responded by increased erythropoiesis. This adaptive response provided greater numbers of erythrocytes and thus a higher amount of circulating hemoglobin to deliver O2 for metabolism.

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Cardiovascular, respiratory, and metabolic responses to upper body exercise.

D R Pendergast (1989)

Many studies have suggested that arm exercise, particularly in the supine position or with arms elevated, is more stressful than leg exercise. Arm exercise at a given workload is typified by cardiac output and oxygen consumption values slightly higher and heart rate, blood pressure, ventilatory and blood lactic acid responses that are significantly higher than those observed during leg exercise. Part of the increased physiological stress during arm exercise may be due to sluggish kinetics of oxidative metabolism and increased glycolysis leading to lactic acid production and accumulation in blood. This physiological state would lead to a cardiovascular and respiratory pressor effect. The limitations of VO2 adjustment in the arms are not due to cardiac or muscle blood flow limitations as these are quick to adjust and reach higher absolute levels than during leg exercise. Specific arm training increases the VO2 adjustment, and the physiological values in these subjects during arm exercise are similar to those observed during leg exercise.