July 2009 - Living Healthfully

Because of carbon dioxide retention, patients tend to have enlarged chest (barrel chested). And since carbon dioxide occupies most of the lung areas, there will be no more room for oxygen diffusion among the alveoli. and therefore an emphysemic patient becomes hypoxic (loses significant amount of blood oxygen).

And how bad this condition is? A cell, a tissue, or an organ needs oxygen to function properly. Without oxygen, the body will become defective.

To compensate, patient is expected to have rapid breath cycles. Pulmonary hypertension also may ensue due to decreased lung oxygenation. Eventually the right side of the heart will exert more effort to counteract pressure in the pulmonary circulation. when the heart gets tired of the set-up, it eventually ceases to pump. This will lead to congestive heart failure, and generalized edema.

from www.heart-watch-blog.com

And so what can we conclude from these clinical manifestations? If I were you I would quit smoking, and start to take good care of myself. a healthy lifestyle always gives us rewards.

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Make Use of Your Hormones to Improve Exercise results...the Natural way! (LAST PART)

July 6th 2009 17:59

Glucose Utilization during Exercise- A Function of the Insulin
Insulin, though not mentioned in Table 2, is also important in both aerobic and anaerobic exercise. As discussed, during these two types of exercise, glucose is one of the fuels that energize the body. And so glucose production has been shown to be stimulated by the catecholamines (and at rest, the glucagon). But how can the glucose produced and delivered to the blood be consumed by the cells in the body? The answer to this is through insulin coming from the pancreas.

Insulin facilitates entry of glucose into the cells in order for it to be transformed into energy (glucose utilization). Without insulin, glucose would only be left within the plasma and would be useless. This would also lead to complications as seen in Diabetes Mellitus patients.

The effect of insulin to the body processes is naturally delayed, as seen in Figure 4. We can only observe sudden rush in insulin secretion after exercise (Scheen et al., 1998). This is because the catecholamines limit such secretion during exercise, since the body needs to produce glucose into the blood as energy reserves. And presence of insulin would impede such process.

However after exercise when glucose within the muscle fibers and other cells is depleted, the glucose reserves in the blood have to be mobilized towards the cells to replenish such depletion. This is where insulin comes into play.

Figure 4. Mean profile of Insulin Secretion Rate (ISR) in the resting condition (unshaded) and in the exercise condition (shaded)

The above concepts are useful when choosing what type of exercise a Diabetes Mellitus (DM) patient (especially Type I) is to perform. If we are to exercise a DM patient, what type of exercise is applicable? In order to answer this we have to consider which type of exercise stimulates more glucose production. Obviously this would be the anaerobic type. But as stated glucose produced in this occasion stays in the blood. And so the tendency to have hyperglycemia is natural. And among the normal individuals, this would not be a problem since post-exercise hyperinsulinemia occurs immediately. This hyperinsulinemia would then control excessive blood sugar. But among DM patients, hyperinsulinemia does not take place. And so hyperglycemia remains leading to worsening of the patientsÂ’ conditions.

On the other hand, what happens during aerobic exercise? Scheen et al. (1998) do not deny that glucose in blood increases during aerobic exercise (but not as much as in anaerobic). And together with this insulin secretory rate decreases. Nevertheless this would not be a problem. Since the glucose level during aerobic exercise does not cause hyperglycemia, unlike in anaerobic exercise. Also, increased peripheral blood flow augments total insulin delivery to muscles and thus compensates at least in part for the decreases plasma insulin concentration.

We can therefore conclude that aerobic exercise is better among DM patients than anaerobic exercise. However if we still opt to continue with anaerobic programs, we have to ensure that patient has administered insulin infusion before activity.

Oxidation in Aerobic Activity- A Role of the Thyrotropin and Thyroid Hormones
Another question that has to be answered is this: how does the body constantly sustain oxygen to produce aerobic energy? This is through the thyrotropin (TSH) and thyroid hormones. According to a certain Dr. Kennedy, TSH and the thyroid hormones control the rate of oxidation or oxygen utilization in energy production. Figure 5 shows the increase in TSH in response to aerobic exercise.

Figure 5. Mean plasma TSH during resting condition (unshaded) and exercise condition (shaded).

Without TSH and the thyroid hormones, energy from fats cannot be utilized. This is especially manifested in patients with hypothyroidism, as their physique shows increased fat deposition.

On the other hand excess of these hormones further increases metabolism and fat utilization. This condition results in being ectomorph (as in patients with hyperthyroidism).

Growth in Exercise

Lastly, let us talk about growth in exercise. Growth is another important result of exercise. In an individual exposed to long-term exercise, one of the most significant manifestations of growth is hypertrophy of muscles. We can especially observe this muscle building process during resistance training exercise, which might be considered as anaerobic in nature.

In the case of a muscle fiber, it must be broken down systematically through resistance training. The fiber responds with an increase in the synthesis of new contractile proteins that result in the fiber becoming larger and stronger. This growth response is the result of the presence of potent anabolic (muscle-building) hormones whose function is to promote protein synthesis. And so we can infer that protein synthesis does not only occur to produce energy. It also occurs with the aid of such hormones in order to promote growth especially at the muscular level. The anabolic hormones involved are GH, IGF-1, and the testosterone (Taylor et al., 2000). As more fibers are involved, a greater hormonal response is necessary, and thus greater changes in whole muscle are possible (Stout).

Conclusion
Truly the endocrine system presents different facets of response during exercise. A more comprehensive description of these facets would be more complicated. And so this discourse has presented the basic activities our endocrine glands do in order to sustain homeostasis and provide adaptations to the body in order for it to keep up with the demands of activities. Understanding these basic concepts can give us a huge foundation if we are to pursue more advanced endocrinology. These concepts would also come in handy when we are to choose which exercises are we to prescribe for patients with different conditions and different needs.

And so if we opt to improve strength, agility, and speed, and increase energy storage for immediate use, then anaerobic exercise will be the exercise of choice. It should be since it utilizes our catecholamines and the growth hormones to achieve our goals. Variants of aerobic exercise are those that involve high intensity but low duration exercises, like weights training, sprint, tennis, and even soccer.

But if our goal is weight and fat loss, or even increase in general body endurance then aerobic exercise shall be our choice. It does not only maximize the use of oxygen to burn our fats, it also teaches our body to conserve energy in order to prevent immediate, untimely muscular and cardiovascular fatigue. Aerobic exercise does this through its effect on the bodyÂ’s release of cortisol, thyroxine, and sex hormones. Aerobic activity or exercise includes jogging, brisk walking, marathon run, treadmill exercise for more than 20 minutes, and even cross-country skating.

And lastly take note that the time of the day when we exercise affects the results. And so if we want to maximize the use of our hormones (like growth hormones and thyroid hormones) for improved growth and fat burning, then evening exercise will do the trick.

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Make Use of Your Hormones to Improve Exercise results...the Natural way! (Part 3)

July 3rd 2009 11:06

The table featured last time shows a simple concept on hormone reactions during exercise. As seen in the table glucose and glycogen breakdown during exercise is mainly the role of the catecholamines- the epinephrine and the norepinephrine. They ensure that these energy sources are available in the blood during activities. However one of the catecholamines, the norepinephrine also contributes to lipolysis or fat metabolism, transforming it to another consumable energy. Free fatty acid (FFA) mobilization that leads to lipolysis is being triggered by the GH. Protein synthesis on the other hand, has been shown to be stimulated again by the GH and others like testosterone, cortisol, and IGF-1. These hormones create and break down protein to provide growth and energy as well (gluconeogenesis).

It is also notable from the table above that each hormone has its own stimulant for release. As mentioned earlier, hormone response depends on the type of activities an individual is performing. As with this discourse, we focus on the reactions of the hormones to the different forms of exercise. And we shall see that the catecholamines are stimulated by performance of moderate to intense exercise. But later on we shall see that the release of these hormones is more sensitive when the body does an intense type of activity (anaerobic). On the other hand, prolonged exercise triggers cortisol release while light to moderate exercises stimulate estrogen release (aerobic). In addition, GH, testosterone, and IGF-1 are activated with any type of exercise but more of the aerobic (Marks and Kravitz, 2000).

What should be understood from the above concepts? We have to understand that upon anaerobic activities, when the body gets its energy from glucose and glycogen (needless of oxidative process), the catecholamines mainly come into play. But for aerobic activities, catecholamines partially affect energy production, and other hormones more dominantly act into the scene. These hormones include cortisol, GH, IGF-1, estrogen and testosterone. The reason for this is that aerobic activities require more complex sources of energy other than glucose and glycogen, namely fats and proteins. And fat-protein utilization is being handled by the hormones previously discussed.

Catecholamine and Glucose Response to Intense/ Anaerobic Exercise
During an intense exercise, when there is a huge demand for glycogen and glucose, rapid muscular and hepatic glycogenolysis takes place. This induces a seven- to eight-fold increase in glucose production as manifested by its concentration in the blood (Figure 1). The reason for this tremendous glucose production is the marked 14- to 18-fold increase in both epinephrine and norepinephrine (Figure 2; A and B). And from the figures below (1 and 2), we can observe the direct relationship between glucose and catecholamine production.

To further emphasize the major role that glucose and catecholamine play in anaerobic activities, we can refer to the works of Marliss and Vranic (2002). In their discourse, they discussed the huge difference between plasma catecholamine concentration during aerobic exercise and plasma catecholamine concentration during anaerobic exercise (Figure 2). If in anaerobic activities, catecholamines respond largely as stated above, in aerobic the plasma concentration of these hormones only increases by two- to four-fold.

What can we infer from these findings? Two points can be conceptualized from the above facts: (1) that though aerobic exercise is more of a fat and protein burner, we cannot elude from the idea that small percentage of energy used also comes from glucose as manifested by increase in glucose production and catecholamine level; but (2) since anaerobic exercise is more of a glycogen/glucose burner, more catecholamines are utilized by such exercise than aerobic to produce a greater amount of plasma glucose.

Figure1. Comparison of responses during 40 minutes of moderate intensity exercise (aerobic/boxes) and 15 minutes of intense exercise in normal young male subjects (anaerobic/circles); Y-axis- GP for glucose production; X-axis- min for minutes of exercise.

Figure2. Comparison of responses during 40 minutes of moderate intensity exercise (aerobic/boxes) and 15 minutes of intense exercise in normal young male subjects (anaerobic/circles); Y-axis- catecholamines (A-Norepinephrine; B-Epinephrine); X-axis- min for minutes of exercise.

Dominating Hormones during Aerobic Exercise
First, let us discuss another possible reason why the catecholamine plasma concentration also increases up to a certain extent in aerobic exercise. Aside from the reason stated earlier, we also have to remember that catecholamines, especially the norepinephrine (Figure 2 showing norepinephrine level is greater than epinephrine level during aerobic activity), play an important role in lipolysis. And in aerobic exertion, lipolysis is one of the important processes needed to utilize fat as one of the energy sources. And so it would be justifiable for the body to somehow increase its catecholamine production in anticipation for lipid/ fatty acid use.

But again as discussed in the previous parts, this catecholamine production during aerobic exercise is no match to the catecholamine production during anaerobic exercise. This is because during aerobic exercise, the body shifts from usage of glucose as energy source to utilization of fats and proteins with aid of oxidation.

How does the body carry out this utilization shift? The body is able to manage such shift with the aid of the following hormones: cortisol, GH, estrogen, testosterone, and IGF-1. As the endocrine system senses that the body is into aerobic activity, it all the more stimulates GH, estrogen, and cortisol to be secreted to decrease glucose uptake. This mechanism would then possibly decrease glycogenolysis and so glucose level in the blood will not increase as much as in anaerobic exercise. And as glucose uptake is decreased, GH, estrogen, and cortisol continue their roles as they promote fatty acid mobilization and protein utilization (gluconeogenesis). These hormones are being supported by other hormones like testosterone, and IGF-1.

But does this mean that during anaerobic exercise cortisol, GH, estrogen, testosterone, and IGF-1 are not being activated? No. In fact both aerobic and anaerobic exercises are shown to stimulate these hormones (Table 2). And what we have to understand now is that if in anaerobic exertion, the more dominant hormones are the catecholamines, in aerobic they are cortisol, GH, estrogen, testosterone, and IGF-1 (Marks and Kravitz, 2000; Robergs and Roberts, 1997).

Figure 3 shows cortisol and GH behavior during prolonged/ aerobic exercise. And as we shall see, the group under the exercise condition was noted to have an increased plasma cortisol and GH concentration within the exercise, compared to the group under resting condition. These increases again mean that the body anticipates cortisol and GH usage by the cells.

Figure 3. Mean profiles of plasma cortisol and GH secretory rates in the resting position (unshaded) and in the exercise (shaded).

Unfortunately we failed to gain clear sample graphs that compare plasma concentration of cortisol and GH in aerobic and anaerobic exercise. We are also unable to search graphs that examine testosterone, estrogen, and IGF-1 behavior during exercise. But despite of these, most researchers agree to the fact that these hormones do really increase their activities especially during aerobic exertion.

TO BE CONTINUED...

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