# Metabolism



## sara (Aug 11, 2004)

*Factors affecting the BMR*
_A person's BMR is influenced by a number of factors working in combination, including_:
Body size - larger adult bodies have more metabolising tissue and a larger BMR. 

Age - metabolism slows with age, due to a loss in muscle tissue but also due to hormonal and neurological changes. Beyond maturity there is a gradual fall in BMR per kilogram body weight of about 10 per cent per year.

Growth - infants and children have higher energy demand per unit of body weight due to the energy demand of growth and the energy demand for maintenance of body temperature. 

Gender - generally, men have faster metabolisms than women because they tend to be larger and have less body fat.

Genetic predisposition - the metabolic rate may be partly decided by a person's genes.

Amount of lean muscle tissue - muscle burns kilojoules voraciously.

Amount of body fat - fat cells are sluggish and hardly burn any kilojoules at all; they need next to no energy to maintain themselves.

*Hormonal and nervous controls *  - BMR is controlled by the nervous and hormonal systems; hormonal imbalances can influence how quickly or slowly the body burns kilojoules.

Dietary deficiencies - for example, a diet low in iodine reduces thyroid function, which slows the metabolism.

Environmental temperature - if temperature is very low or very high, the body has to work harder to maintain its normal body temperature, thus increasing the BMR.

Infection or illness - BMR increases because the body has to work harder to build new tissues and to create an immune response.

*Crash dieting, starving or fasting *  - eating too few kilojoules encourages the body to slow the metabolism to conserve energy; BMR can drop by up to 15 per cent. Spontaneous activity is also reduced, achieving a further 15 per cent reduction in energy expenditure. These two combine to reduce energy usage and to conserve life. There is also loss of lean muscle tissue, which further contributes to the drop in BMR.

Amount of physical activity - hard working muscles need plenty of energy to burn. Regular exercise increases muscle mass and 'teaches' the body to burn kilojoules at a faster rate, even when at rest.

Drugs - some drugs, like *caffeine or nicotine, can increase the BMR*  

For more Info>>>>>>>>>>>> http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Metabolism_explained?OpenDocument


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## atherjen (Aug 12, 2004)

great post Sara.


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## sara (Aug 12, 2004)




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## oaktownboy (Aug 13, 2004)




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## AlphaFemale (Aug 14, 2004)

Wow, great post. Does anyone know foods that are high in iodine? Seaweed maybe??


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## sara (Aug 14, 2004)

Dietary sources of iodine are plentiful. For most Americans, a deficiency in iodine is not a risk. One teaspoon of iodized salt contains more than 300 mcg of iodine, so it is not difficult to obtain or exceed the small amount needed to meet the daily requirement. The RDA for iodine is 150 mcg a day for adults.

Other sources of iodine include dairy products made from milk produced by cows grazing in coastal soil, as well as fruits and vegetables grown in coastal soil. Various vegetables from the sea, such as kelp and seaweed, contain very high amounts of iodine as well. Commercially prepared baked goods, such as cakes and breads, frequently contain dough conditioners that have iodine. Most salty, high-sodium processed snack foods, however, contain very little iodized salt and almost no iodine.

The trace mineral is also found in most multivitamin and mineral supplements. Concentrated sea kelp tablets are another potent source of iodine. 

http://www.wholehealthmd.com/refshelf/substances_view/1,1525,888,00.html


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## sara (Aug 14, 2004)

*Iodine in Diet*: Food Sources
Iodized salt is the primary food source of iodine. Iodine is also widely available in seafood; cod, sea bass, haddock, and perch are good sources. Kelp is the most common vegetable seafood that is a rich source of iodine. Dairy products and plants grown in soil that is rich in iodine are also good sources.


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## AlphaFemale (Aug 14, 2004)

Thanks Sara. I guess I'm getting plenty of it then!


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## hardasnails1973 (Aug 26, 2004)

USE IODINE PATCH TEST TO DETERMINE NEEDED LEVELS.  PAINT AN IODINE PATCH FROM TINCTURE ON ARMS IN A SMALL SILVER DOLLAR. IF THE PATCH DISAPPEARS WITH IN 24 HOURS YOU ARE LOW ON IODINE.  SOME PEOPLE EAT ALL NATURAL FOODS AS I DO AND I HAVEN;T SALTED MY FOOD FOR MANY YEARS.  i HAVE SEVERE LOW THYROID SYMPTOMS AND MY PATCH WAS GONE IN AN HOUR TIME.


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## sara (Aug 26, 2004)

Is it bad to have low Idone level?


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## Emma-Leigh (Aug 27, 2004)

sara said:
			
		

> Is it bad to have low Idone level?


Iodine deficiency is pretty rare in western countries... 

But the main use of Iodine in the body is in the thyroid for the formation of thyroid hormone - and this is essential in maintaining your metabolism.

If your iodine intake is too low, you will not necessarily develop hypothyroidism, but you may get a goitre (your thyroid gland 'hypertrophies' to try to increase thyroid hormone synthesis). If deficiency is more severe you can get some signs of hypothyroidism (cold, tingling, weight gain etc) and in very severe cases you get severe signs (myxedema) such as changed personality (you become slow mentally), you start to lack facial expression with your skin becoming thick, dry and rough and your eyes and lips get 'swollen and puffy'.  Your hair also becomes dry and breaks and falls out. You get sick more often, become slow to heal if you cut yourself... Stuff like that. Your body basically 'slows down'...

But, as I said, an iodine deficiency severe enough to cause that degree of thyroid suppression is VERY rare in western countries so do not go overdoing on Iodine as you can also get problems from that!!


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## soxmuscle (Aug 27, 2004)

Great post, I've been only a day already and I've learned alot.

Thanks guys... and girls...


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## Dale Mabry (Aug 27, 2004)

Emma-Leigh said:
			
		

> Iodine deficiency is pretty rare in western countries...




That is because most Americans overeat and add an ungodly amount of salt to their food.  If you drop this source like most healthy folk do, you can become severely lacking in iodine.


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## sara (Aug 27, 2004)

Thanks for the answer Emma


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## Emma-Leigh (Aug 27, 2004)

sara said:
			
		

> Thanks for the answer Emma



Welcome


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## musclesmcgee (Aug 29, 2004)

Thanks for the info sara--I have graves' disease ( a thyroid disorder) which of course, affects my metabolism..Any suggestions on how to train better ( more efficiently) for someone like me? I have thought of a heart rate monitor during cardio to help stay in my target range ( my heart beats slower than average.. everything in my body is slow)..Although most people who work out as I do should consume upwards of 1600-1800 cal a day, I consume between 1100-1300 or else I gain weight. I feel as if I am stuck.


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## Emma-Leigh (Aug 29, 2004)

musclesmcgee said:
			
		

> I have graves' disease ( a thyroid disorder) which of course, affects my metabolism..Any suggestions on how to train better ( more efficiently) for someone like me? I have thought of a heart rate monitor during cardio to help stay in my target range ( my heart beats slower than average.. everything in my body is slow)..Although most people who work out as I do should consume upwards of 1600-1800 cal a day, I consume between 1100-1300 or else I gain weight. I feel as if I am stuck.



Hey There 

Ahhh.. That sux... I am sorry you have to deal with that.



HRM are definately handy - they will help you stay in your THR (although I suggest you adjust it for your Resting heart rate as it will be slower than the average person of your age). 

So to find between 75% and 90%:
220 - age = HRmax
HRmax - resting heart rate = A 
A x 75% = B 
A x 90% = C

So B + Resting HR = The low end of target HR (75%)
C + Resting HR = High end of target HR (90%)


Anyway - How you should train will depend on your training goals? Also, what are you currently doing in your training? What is your diet like? Are you on meds?


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## sara (Aug 29, 2004)

musclesmcgee said:
			
		

> Although most people who work out as I do should consume upwards of 1600-1800 cal a day, I consume between 1100-1300 or else I gain weight. I feel as if I am stuck.



You won't be gaining fat weight if you consume 1600 cals a day of clean food.. the first week or two you might gain some Water weight


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## MTN WARRIOR (Aug 30, 2004)

sara said:
			
		

> *Factors affecting the BMR*
> _A person's BMR is influenced by a number of factors working in combination, including_:
> Body size - larger adult bodies have more metabolising tissue and a larger BMR.
> 
> ...


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## Dale Mabry (Aug 30, 2004)

The drop in metabolism associated with age is directly related to loss in LBM.  If you do not lose LBM, your metabolism will not slow down.


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## GoalGetter (Aug 30, 2004)

Great info! Thanks!

  But here I go again, with the caffeine question (I just posted a question regarding coffee).

  So, caffeine? Good? I can drink my coffee in the morning and stop feeling bad about it?


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