Exercise metabolism and

Graham TE, Rush JWE, Van Soren MH. Caffeine and exercise metabolism and performance. Can J Appl Physiol 1994 19(1) 111-138. 

Carbon dioxide is produced as a byproduct of exercise metabolism, and breathing is stimulated during exercise to remove this CO2 excess. In this case, however, all the metabolically produced CO2 is removed and there is no measurable increase of CO2 dissolved in the blood. Furthermore, inhaled CO2 during exercise results in an increase of dissolved CO2 just as it did at rest. This difference between responses to inhaled CO2 and metabolically produced CO2 has baffled scientists and engineers for many years. Exercise apparently recruits different respiratory mechanisms to compensate for CO2 produced internally. Some (Whipp, 1981) have... 

Lambert, E.V., Goedecke, J.H., van Zyl, C., Murphy, K., Hawley, J.A., Dennis, S.C., and Noakes, T.D. High-fat diet versus habitual diet prior to carbohydrate loading effects on exercise metabolism and cycling performance. Int. J. Sports Nutr. Exerc. Metab. 11, 209-225, 2001. 

Horton, E. S., and Terjung, R. L., eds. 1988. Exercise, Nutrition and Energy Metabolism. New York Macmillan. 

Metabolic acidosis is caused by the release into the bloodstream of excessive amounts of lactic acid and other acidic byproducts of metabolism. These acids enter the bloodstream, react with hydrogen carbonate ion to produce H2CX)5, and shift the ratio HC03 /H2C03 to a lower value. Heavy exercise, diabetes, and fasting can all produce metabolic acidosis. The normal response of the body is to increase the rate of breathing to eliminate some of the CO,. Thus, we pant heavily when running uphill. 

Saltin, B. Costill, D.L. (1988). Fluid and electrolyte balance during prolonged exercise. In Exercise, Nutrition, and Energy Metabolism (Horton, E.S. Teijung, R.L., ed), pp. 150-158, MacMillan. New York. 

A knowledge of normal metabohsm is essential for an understanding of abnormalities underlying disease. Normal metabolism includes adaptation to periods of starvation, exercise, pregnancy, and lactation. Abnormal metabolism may result from nutritional deficiency, enzyme deficiency, abnormal secretion of hormones, or the actions of drugs and toxins. An important example of a metabolic disease is diabetes mellitus. 

Powers, S., Byrd, R., Tulley, R., and Callendar, T., Effects of caffeine ingestion on metabolism and performance during graded exercise, European Journal of Applied Physiology, 50, 301, 1983. 

Weir, J., Noakes, T.D., Myburgh, K., and Adams, B., A high carbohydrate diet negates the metabolic effects of caffeine during exercise, Medicine and Science in Sports and Exercise, 19, 100, 1987. 

Q. Ding, S. Vaynman, P. Souda, J. P. Whitelegge, and F. Gomez-Pinilla. Exercise Affects Energy Metabolism and Neural Plasticity-Related Proteins in the Hippocampus as Revealed by Proteomics Analysis. Eur. J. Neurosci., 24(2006) 1265-1276. 

The calorific capacity of amino acids is comparable to that of carbohydrates so despite their prime importance in maintaining structural integrity of cells as proteins, amino acids may be used as fuels especially during times when carbohydrate metabolism is compromised, for example, starvation or prolonged vigorous exercise. Muscle and liver are particularly important in the metabolism of amino acids as both have transaminase enzymes (see Figures 6.2 and 6.3 and Section 6.4.2) which convert the carbon skeletons of several different amino acids into intermediates of glycolysis (e.g. pyruvate) or the TCA cycle (e.g. oxaloacetate). Not all amino acids are catabolized to the same extent... 

Day WW, Weiner M. 1991. Short communications Inhibition of hepatic drug metabolism and carbon tetrachloride toxicity in Fisher-344 rats by exercise. Biochem Pharmacol 42 181-184. 

Mechanism of Action An antihypertensive that blocks endothelin-l, the neurohormone that constricts pulmonary arteries. Therapeutic Effect Improves exercise ability and slows clinical worsening of pulmonary arterial hypertension (PAH). Pharmacokinetics Highlybound to plasma proteins, mainlyalbumin. Metabolized in the liver. Eliminated by biliary excretion. Half-life Approximately 5 hr. 

G. H. Raymer, H. J. Green, D. A. Ranney, G. D. Marsh and R. T. Thompson, Muscle metabolism and acid-base status during exercise in forearm work-related myalgia measured with 31P-MRS. /. Appl. Physiol., 2009,106,1198-1206. 

Because insomnia is often transient and intermittent, the prolonged administration of estazolam is generally neither necessary nor recommended. Caution should be exercised in prescribing this hypnotic for elderly or debilitated patients, as well as for those with impaired renal or hepatic function, because of increased sensitivity or reduced capacity to metabolize and eliminate the drug. The recommended initial dose is 1 mg, but some may need a 2 mg dose. For the elderly, a 0.5 or 1 mg dose is appropriate. 

The effects of coenzyme Q10 on coronary artery disease and chronic stable angina are modest but appear promising. A theoretical basis for such benefit could be metabolic protection of the ischemic myocardium. Double-blind, placebo-controlled trials have demonstrated that coenzyme Q10 supplementation improved a number of clinical measures in patients with a history of acute myocardial infarction (AMI). Improvements have been observed in lipoprotein a, high-density lipoprotein cholesterol, exercise tolerance, and time to development of ischemic changes on the electrocardiogram during stress tests. In addition, very small reductions in cardiac deaths and rate of reinfarction in patients with previous AMI have been reported (absolute risk reduction 1.5%). 

As complex as the regulation of carbohydrate metabolism is, it is far from the whole story of fuel metabolism. The metabolism of fats and fatty acids is very closely tied to that of carbohydrates. Hormonal signals such as insulin and changes in diet or exercise are equally important in regulating fat metabolism and integrating it with that of carbohydrates. We shall return to this overall metabolic integration in mammals in Chapter 23,... 

Graham TE. Caffeine and exercise metabolism, endurance and performance. Sports Med 2001 31 785-807. 

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