Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: neilep on 02/03/2009 17:58:14
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Some of ewe may or may not know that since June last year I have been on a health drive.
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Above is the instrument of torture ! health !
Actually, the ' thing ' standing on it is is enuff hard work !!
What I want to know is , am I getting just as much exercise achieving the same number of calories burned but at different speeds ?
Let me explain further ...!! ( I will try)...Sometimes I manage 6 miles in one hour and I sweat profusely !!!..a real lot..I am soaked !!!!..............other times I will stroll a fast work at 4mph and take a further 30 minutes but I will sweat a whole lot less. Now then, I have burned the same number of calories but at 4mph I have sweat no where near as much as if I am going faster......Am I achieving the same level of exercise even though one makes me sweat far more than the other but the calories burned remain the same ?
Gosh, I hope I have explained this right !!
Thanks
Neil
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ps: incidentally..to date (2nd March 2009)..I have travelled 1262.5 miles and burned 153119 calories since June 2 2008 !....which is nice !!
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I was told at physical therapy it was not how fast I went but just maintaing my heart at a target rate for a certain sustained time frame... but at the same time you are always told that different rigorous activities burn more or less calories so I would tend to believe you burn more in that faster paced time frame...
It seems the the treadmill says different...eh ..like the distance etc...determined the burn rate and not the vigor with which you did it...So I really don't get it... good question..
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Thanks Kareny Mam,
Yes, faster exercise does burn more calories at a faster rate over a shorter period of time, but If I slow down and extened the rate of time then I can burn ther same number of calories but at a slower rate. My question was/is does the fact that at the slower rate , that although I sweat a lot less, still give me the same amount of fitness benefit ?
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Isn't this something to do with homo statis...the sweating and stuff? I'm not sure as it is biology stuffs.
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Karen's right. It's all about heart rates. In the range of roughly 50-80% of your maximum heart rate you'll get heart health benefits. At the upper end of that range, you'll also be improving your aerobic fitness and endurance more than at the lower end. If you want more details, this pretty much agrees with what I've read elsewhere:
http://walking.about.com/cs/fitnesswalking/a/hearttraining_2.htm
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I found this article a long time ago in cyberspace... Sadly, I don't know who to give credit to... I think it's one of the best pieces written on the matter. I hope it helps
Where weight reduction is discussed in terms of a reduction of the body fat component, unsuitable recommendations are quite often made. It becomes apparent that there seems to be a misunderstanding between the terms optimal fat burning and optimal fat reduction.
Fat burning describes a form of energy supply by the body. Here free fatty acids (FFA), which are created during the break-down of fat deposits, are "burned without flame", i.e. oxidized. This process is, in comparison to energy extraction from glucose, quite complicated and cumbersome, but it sets free much more energy for the same amount of "fuel". Fat burning takes place all over the body, all of the time. Fat reduction describes a long lasting process of body weight reduction through the reduction of the body fat component. Fat reduction and fat burning have to initially be viewed as independent of each other. While fat burning takes place constantly and all over the body, a fat reduction will only take place if the body receives less energy than it needs over a longer period of time. In this relation we talk about a negative energy balance.
Relative and absolute energy extraction
In relation to the required energy, the lower the strain on the body, the more fat will be burned. During rest phases, virtually the entire energy requirement of the body is supplied from free fatty acids. The relative energy extraction from fats, which could be expressed in percent, is very high. The absolute energy quantity, measured in Kcal, is, on the contrary, very low during rest phases.
If the body is subjected to a low-intensive endurance effort (for example extensive jogging with 60% of the maximum heart rate), it will require vast amounts of energy in a relatively short time (depending on the intensity of the effort), and "cranks up" the metabolism. This not only increases the fat metabolism activity, but also in a higher proportion the metabolic transformation of glucose, since the body can extract energy from glucose faster. If one observes the energy consumption during the exercise, a relatively higher percentage of energy is actually burned from carbohydrates than during rest phases. However, the fat metabolism still holds a proportion of around 80%.
The high relative component of energy supply from FFA is the reason why it is often suggested to use low-intensity endurance training if fat reduction is to be the goal. For beginners this makes sense, because training with more intensive methods may well be too much for them. One may not draw the conclusion, however, that there is a heart rate limit, above which energy is no longer created from fats and will not lead to further weight loss. On the contrary, if one would run the same time length at a heart rate of 150 to 160 bpm, one would need significantly more energy, both from carbohydrates and fats. Both methods of metabolism are "cranked up", even if the relative carbohydrate metabolism tends to be more dominant. The body does not switch from fats to carbohydrates as a rule, but rather supplements one with the other when the energy requirements are higher.
"The Fat burns in the fire of carbohydrates"
This relationship will be demonstrated with the following calculation:
Slow running at a heart rate of around 120 bpm consumes approx. 8 Kcal. With a relative energy extraction from fats of around 80%, 6.4 Kcal per minute are burned from fats. Running at around 150 to 160 bpm consumes approx. 15-18 Kcal per minute. Even if the proportion of supplied energy from FFA only lies around 50-60%, at least 9 Kcal per minute are created from fats. If we assume that both runners exercise for the same amount of time, then the slightly faster runner will have used twice the energy than the slower runner. If both want to lose weight and have an identical food intake, it would be quite presumptuous to say that the runner training with a pulse of 120 will have a higher weight loss than the one running with a pulse of 150 to 160. But it is exactly this which is widely claimed.
A pure fat metabolism training is thus not the ultimate solution for fat reduction. Whether a body accesses its fat reserves depends solely on the energy balance. If this balance is negative, i.e. more is consumed than taken in, the body has no other choice than to take the energy from where it put it exactly for that purpose in the first place, namely the fat deposits. The carbohydrate storage in muscles and liver will also need to be replenished after training. This also flows into the general energy balance, because the body accesses even more fat deposits to achieve this replenishment. This phenomenon is also called the afterburning effect. Further, no healthy, well-nourished individual will use its muscular protein to metabolize. The assumption, that a calorie-reduced diet and accompanying endurance training will lead the body to burn its muscular protein, is not true under any circumstances. Muscle cells are only reduced through inactivity. This process is called atrophy.
In other words: Fat metabolic training is not equal to fat reduction training! Certain competitive sportsmen and women undertake a dedicated fat metabolic training for a couple of hours in regular intervals to optimize exactly this energy supply process for their kind of sport. This long-term endurance training is especially important for marathon runners and cyclists. But if the requirement is to consume more energy than is taken in, it is not advisable to transpose these training methods into the mass and health sport segments.
What does energy balance mean in practical experience ?
From the above statements we can deduce that, in order to lose weight, the energy consumption must be increased and the calorie intake lowered. If we take a male of 75kg weight, the base metabolic rate lies at approx. 1600 Kcal. The daily energy requirement is calculated from base metabolic rate plus activity and would lie, for the above person, at a maximum of 2000 Kcal, if we assume that the man will carry out only office work and no other sport activity. The daily energy requirement, which is in addition to the amount of sports dependent on age, sex and body weight (muscle mass), can be easily increased through sports by up to 30%. Fat reduction can therefore only be made possible, if one reduces the calorie intake and secondly increases the consumption through sports. There is no patent recipe for this. A diet, which overemphasizes certain food groups, is just as absurd as a selective diet or weight-loss drinks. It is up to each and every one of us to determine how to achieve the fat reduction, since at the end it is only a question of energy balance.
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Is that an arm on the wall!?!?!?