Exercise training duration

Phillips SM, Green HJ, Tamopolsky MA, et al. Effects of training duration on substrate turnover and oxidation during exercise. JAppl Physiol 1996 81 2182. 

Exercise intensity, duration, frequency, training experience, and total energy intake can all presumably affect protein requirements with total energy intake having the greatest impact,2S2 283 followed by training experience, jjjost dietary... 

The observation of possibly increased IMCL levels in highly trained athletes led to a second focus of research in the field of sports medicine. Besides carbohydrates, lipids are the major fuel of skeletal muscle during work and rest. A variety of questions have to be answered. It was examined, whether exercise of various intensities alters IMCL levels, whether those changes depend on the duration of exercise, and finally, how IMCL are replenished during post-exercise recovery. 

The effects of aerobic exercise of different workloads and durations on IMCL were examined in several studies. Twelve well-trained male Caucasian subjects participated in these studies. All volunteers were in good health and none was taking any medication. BMI and V02max were comparable in all volunteers. 

Some of the responses by the body to anaerobic exercise are visually obvious. Greater strength, speed, and muscle development are reasons that athletes emphasize anaerobic training. However, research has shown that these results are not easily predicted, and even the effects on the amouit of muscle mass are not entirely clear (9). The effects of these short-duration exercises on cardiopulmonary function and on nutritional requirements are minimal. 

Several Important training variables are known to Influence the magnitude of the biochemical response. These Include the duration of the training program, the Intensity of the exercise effort, the duration of each exercise bout (mlnutes/day), and the frequency of exercise (l.e., days/week). 

The likelihood for the development of symptoms following inhalation exposure and the nature and severity of respiratoiy tiact injuiy depends on a number of factors, which include the chemical namre of the smoke, concentration and toxic potency of inhaled materials, particle size and vapor proportion, duration of exposure, water solubility, respiratory minute volume, and personal characteristics (e.g., differential susceptibility, exertion). During training and operational use, exercise will result in an increased respiratory minute volume (effect of tachypnea and increased tidal volume) and thus a greater inhalation exposure dose. Most of the more soluble inhaled material will tend to predominantly affect the upper airways, and the less soluble materials affect mainly the peripheral airways and alveoli. 

Exercise - even of short duration - causes changes in blood serum constituents, possibly due to leakage of intracellular components, e.g. enzymes from muscles. Continuous training may cause hemodilution this may in turn lead to apparently too low values of blood components. Changes caused by physical strain may even be seen in urinary excretion of trace elements, as exemplified by a 5-fold Increase of the urinary chromium excretion after running for 2 h (Anderson et al., 1982a). 

As with hypocalcemia, patient education related to self-care is important. The patient should be instructed to drink plenty of fluids, take only the medications prescribed by the physician, refrain from smoking, and exercise once cleared to do so by the physician. Both strength training and weight-bearing exercises are recommended. The patient should increase the time and duration of exercise sessions gradually,... 

In contrast to endurance exercise, resistance exercise results in muscle hypertrophy rather than an increase in amino acid oxidation and mitochondrial biogenesis. If, for example, there are no changes in efficiency of amino acid retention, there must, at some point, be a protein intake in excess of basal requirements to provide the amino acids required for anabolism. The extent of this increased need is again a fimction of the basal state of training, the duration, and the intensity of the training program. 

Horton, T.J., Pagliassotti, M.J., Hobbs, K., and Hill, J.O., Fuel metabolism in men and women during and after long-duration exercise, J Appl Physiol, 85, 1823, 1998. Friedlander, A.L, Casazza, G.A., Homing, M.A. et al.. Training-induced alterations of carbohydrate metabolism in women women respond differently from men, J Appl Physiol, 85, 1175, 1998. 

Up to this point we have examined the influence of acute and chronic exercise on carnitine levels in the muscle, plasma, and urine. The hterature is fairly consistent in that there does not seem to be a depletion of total muscle carnitine and that an acute bout or chronic training does not change these levels. It is important to now focus on the performance aspect of these and other studies. The intent is to ascertain whether carnitine supplementation enhances performance as measured by such variables as VOj max, RQ, exercise duration, blood lactate concentrations, substrate metabolism, and glycogen sparing. There have been several studies that measured all or some combination of tliese markers, and they will be presented in ehronological order to help follow the progression of eamitine researeh. 

Table 6 Duration, distance, and percentage of distance driven by the experts when exercising the CMS during the training phase (N = 11)...

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