cardio intensity/time

[GQSuperman]

anyone have any articles on why it's suggested by many (here on this board) why one does cardio at 65-75% maxHR for 30-45 minutes to promote lipolysis?

are there any articles that show a correlation of lipolysis with HR and when catabolism sets in?

[CutMeUp]

anyone have any articles on why it's suggested by many (here on this board) why one does cardio at 65-75% maxHR for 30-45 minutes to promote lipolysis?

are there any articles that show a correlation of lipolysis with HR and when catabolism sets in?

While exercising our muscles burn both fat and glucose (carbohydrates in the blood) in different proportions. Depending on how an individual exercises muscle can burn fat in a larger proportion to glucose.
When activity is light and easy we tend to burn a much higher percentage of fat. Fat is a slow burning fuel that requires oxygen so if oxygen is delivered to muscle cells in sufficient quantities the cells can easily burn fat for most of its energy requirement. A potential problem for weight loss is lighter exercise burns fewer total calories.
If an individual increases their effort by performing a more intense exercise they WILL burn more calories however, because oxygen cannot always be delivered to the hard-working cells in sufficient quantities, cells are forced to burn more carbohydrates in order to keep up with increasing demand. If the level of exertion continues to increase then glucose eventually becomes the predominant energy source for muscles as this quick-burning fuel does not require oxygen.
It means to burn fat directly we should exercise at a lower level of effort and for longer duration. However some people just don't have the time to exercise for longer periods. The only way to burn fat quickly is to increase the metabolism through anaerobic exercise so we burn the fat indirectly.

http://www.weightlossforall.com/burn%20fat.htm

This is not even from a BB point of view. but it does coincide with what many of the bros here preach. no more running on the treadmill...walk on an incline. since that comes as a shock to many people when they hear it for the first time, here it is from another source. doing it in the morning on an empty stomach to minimze the glycogen store will maximize results.


This may not be exactly what you are looking for, but i just copied it from a post i made yesterday in the diet forum.

[GQSuperman]

but i was interested more in the correlation between Heart rate and lipolysis and how the optimal level of cardio intensity is arrived at.

[GQSuperman]

you do sound a lot like brian11. how many aliases do you have?

[CutMeUp]

but i was interested more in the correlation between Heart rate and lipolysis and how the optimal level of cardio intensity is arrived at.

yea i figured, but i figured i would send that anyway.

you do sound a lot like brian11. how many aliases do you have?

LOL, have those guys not squared that away yet?!?! I'll be brian11 if it makes you guys happy...i aim to please

[Hypertrophy]

Yes, there are numerous studies. Basically it is your Respiratory Exchange Ratio that determines your fuel source. .7 = 100% fat
1.0 = 100% CHO
During graded exercise test, expired gases are measured to give you an RER. As intensity increases, this value also increases. Studies consitently show that an higer percentage of fat is used during lower intensities (<85%) of VO2 max or Heart Rate Reserve.
It is physiological impossible to burn 100% fat!

[GQSuperman]

its vo2 max that indicates when lipolysis occurs? i'm assuming this is an indicator, as it doesn't actually measure lipase or other enzyme activity or endproducts of lipolysis like glycerol or fatty acids. so, is HR just another indicator like VO2? are HR and VO2 related?

[Hypertrophy]

HR and VO2 share a linear relationship. VO2 does not indicate lipolysis. It measures your body's ability to consume oxygen and use it for energy. It tells you how good of aerobic shape you are in. Lipolysis doesn't start at a certain point. Your body increases it reliance on fats the longer you do something. RER measures what fuel you are using, which, in turn tells you when you are utilizing the highest rate of fat as fuel. Say you are hooked up to a metabolic cart and your RER is .8 and your HR is 144, then you know that is an excellent fat burning zone. This usually correlates with about 60% - 75% of VO2 max or Heart Rate Reserve, because HRR tracks more closely with your VO2 max than does Max Heart Rate Formula.

[bluethunder]

Try some keytone test strips. Use them after 2 totally different cardio days. Try at 60-65% 45-60 min. Another time at 75% say 30min. If fat is being oxidized it will show up on the test strip. Ketones are pissed out. This may not be totally scientific but may give you a general clue what works for you. Just make sure you test at same time