Physical activity decreasing

Systemic effects of methamphetamine are similar to those of cocaine. Inhalation or IV injection results in an intense rush that lasts a few minutes. Methamphetamine has a longer duration of effect than cocaine. Pharmacologic effects include increased wakefulness, increased physical activity, decreased appetite, increased respiration, hyperthermia, euphoria, irritability, insomnia, confusion, tremors, anxiety, paranoia, aggressiveness, convulsions, increased heart rate and blood pressure, stroke, and death. 

Type 2 diabetes may be Hrst treated by increasing physical activity, decreasing carbohydrate intake and weight loss insuhn sensitivity can be restored with only moderate weight loss. 

Because methamphetamine elevates mood, people who experiment with it tend to use it with increasing frequency and in increasing doses, although this was not their original intent. The CNS actions that result from taking even small amounts of methamphetamine include increased wakefulness, increased physical activity, decreased... 

The rate of mitochondrial oxidations and ATP synthesis is continually adjusted to the needs of the cell (see reviews by Brand and Murphy 1987 Brown, 1992). Physical activity and the nutritional and endocrine states determine which substrates are oxidized by skeletal muscle. Insulin increases the utilization of glucose by promoting its uptake by muscle and by decreasing the availability of free long-chain fatty acids, and of acetoacetate and 3-hydroxybutyrate formed by fatty acid oxidation in the liver, secondary to decreased lipolysis in adipose tissue. Product inhibition of pyruvate dehydrogenase by NADH and acetyl-CoA formed by fatty acid oxidation decreases glucose oxidation in muscle. 

These animal studies should indicate to the pharmacist that blood flow can, under certain circumstances, be an important patient variable that may affect the absorption of drugs. Patients in heart failure would generally be expected to have a decreased cardiac output and, therefore, a decreased splanchnic blood flow. This could lead to a decreased rate of absorption for drugs when the blood flow rates in Eq. (7) become rate-limiting. In addition, redistribution of cardiac output during cardiac failure may lead to splanchnic vasoconstriction in patients [57], Other disease states and physical activity can also decrease blood flow to the GIT [2 4], Thus, the pharmacist must be aware of the possible effect of blood flow rate, especially alterations in the rate, on the availability of drugs. 

Decreases in physical activity can lead to weight gain. Ultimately, all the calories you eat are not utilized, or burned off. Calories that are not utilized are stored as fat tissue, which... 

Table 2.1 How Modernization Has Impacted Obesity by Decreasing Physical Activity...

Public Places Use of elevators, escalators, and automated doors Decrease in physical activity such as stair-climbing... 

Environmental factors include reduced physical activity or work abundant and readily available food supply increased fat intake increased consumption of refined simple sugars and decreased ingestion of vegetables and fruits. 

There is a decrease in basal metabolic rate with a decline in lean body mass and less physical activity. The caloric requirement may, therefore, be reduced... 

Interpretation of these studies is difficult, because of surface loss of contaminants in the chambers. The decrease in mouse fertility (duplicated in a second experiments ), the decrease in mouse physical activity, and the increase in susceptibility to infections suggest that some functional measurements were more sensitive for detecting effects than conventional histolc c, hematolc c, or growth measurements. It is doubtful, however, whether any of the observed changes could be considered chronic effects, i.e., irreversible or progressive in the absence of continued exposure. 

In skeletal muscle, glucose transport is non-equilibrium, so that an increase in activity of the transporter increases glucose utilisation. Factors that increase the activity of the transporter (e.g. the number of transporter molecules) in the membrane are insulin and sustained physical activity. In contrast, the hormone cortisol decreases the number of transporters in the membrane. This decreases glucose uptake and is one of the effects of cortisol that helps to maintain the normal blood glucose level (Chapter 12). 

Under the conditions when protons accumulate in muscle, the physical activity of muscle is decreased by fatigue, hence the rate of ATP utilisation and, therefore, ATP generation via glycolysis, are decreased. Consequently the rate of lactic acid formation is decreased. It is unclear it protons are directly involved in fatigue. It is discussed in Chapter 13. 

Figure 6.14 An increase in the rate of glucose transport, in response to insulin, which increases the rate of glycolysis. This is achieved by increasing the concentrations of all the intermediates in the pathway, indicated by the arrows adjacent to the intermediates. Insulin, physical activity or a decrease in the ATP/ADP concentration ratio all result in increased rates of glucose transport in skeletal muscle. Insulin increases the rate about fivefold, physical activity about 50-fold.

It is unlikely that the rate of ATP generation in the hver under normal conditions will be decreased to such an extent that ATP/ADP concentration will be seriously affected. However, some extreme physiological conditions, such as intense and prolonged physical activity, prolonged starvation and haemorrhagic shock may result in reduced perfusion of the liver and lack of oxygen that could result in a marked decrease in the rate of ATP generation. The effect... 

Figure 9.23 Properties of the three enzymes that control the flux through the Krebs cycle. During physical activity. The CoASH/ succinyl CoA concentration ratio increases whereas that of ATP/ADP ratio decrease. These changes increase the flux through the cycle.

Physical activity increases blood flow through the muscle by stimulation of cardiac output, by increasing the diameter of arterioles (vasodilatation) that supply the muscle and by decreasing the flow through abdominal and pelvic viscera and the Uver (vasoconstriction) so that more is... 

Inhibition or failure to activate any one of these factors could result in fatigue. The primary change within a muscle fibre that results in fatigue is a decrease in the ATP/ADP concentration ratio. This arises when the demand for ATP by physical activity exceeds the ability of the biochemical processes within the fibre to generate ATP at a sufficient rate to satisfy this demand. The raison d etre for fatigue is to restrict the extent of the physical activity so that the ATP/TYDP ratio does not fall to such low values that sufficient energy cannot be transferred to power processes that are essential to the life of the cell (e.g. maintenance of the ion balance within the cell). Two key questions arise ... 

In the endurance event, the pH does not change but the content of phosphate increases whereas the contents of glycogen and phosphocreatine decrease markedly. The change in phosphate is considered to be responsible for fatigue. Studies using P NMR spectroscopy indicate that the resting content of phosphate is about 1 mmol/L and increases more than 20 fold at exhaustion in these physical activities. 

Figure 13.28 A possible mechanism by which increased levels of tryptophan and/or tyrosine can occur in neurones and lead to fatigue. The mechanism proposes that physical activity increases the entry of tryptophan or tyrosine into the neurones which increases the concentration of the neurotransmitters, 5-hydroxy-tryptamine or dopamine, respectively. The neurotransmitters are present in vesicles in the presynaptic terminal (Chapter 14). (The pathways for the formation of 5-hydroxytryptamine and dopamine are described in Chapter 14.) This enhances the amount release into the synapses which decreases the excitation of 5-hydroxytryptamine or dopamine neurones in the motor control pathway. It is assumed that they are inhibitory neurotransmitters, they will reduce electrical activity in the motor control pathway and hence nervous stimulation of muscle fibres. This results in fatigue. Mechanisms by which physical activity might result in increased entry of these amino acids into the brain are presented in Appendix 13.5.

A decrease in fitness, due to less physical activity, results in ease of fatigue, which further reduces physical activity. 

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