Question for the Cardio Gurus...

[JB3]

Since the women on this board know more about cardio than any man could ever dream, I thought I'd serve my question here, if y'all don't mind.

Has anyone tried eating only protein (no carbs) before morning cardio? Would your body simply use the protein for energy or deaminate it into glucose? I've read that some have had success fighting catabolism using this techinque.

Also, since the aim is to burn mostly fat and keep the intensity low enough as to not stress the body into burning muscle, what % of mhr do y'all normally maintain? I've found that my lactate threshold is roughly 165 bpm, which would equate to roughly 80-85% of mhr. Should I easy off and attempt to maintain an easier pace? And in the same vein, assuming they'd burn the same amount of calories, is 45 min @ 80% mhr equal to 60 min @ 65% mhr? I assume no... why?

Thanks.

 

[JB3]

anyone?

 

[blueyedkowgrl]

i don't really know. but that is a damn good question.. I'd love to see an answer to this one.

 

[skydancer]

I have done this...protein shake with a bit of flax actually while bulking. I can't say chemically how my body used it but I definately didn't have any problems with losing muscle. Of course I wasn't doing a ton of cardio either. 1-2 45m sessions a week.

------------------
The only true wisdom is in knowing you know nothing. - Socrates

 

[Cheetarah]

Keep a moderate pace, stay in your aerobic zone and not your anaerobic zone. You cannot burn fat without the presence of oxygen (hence anaerobic). You can probably find out what your target heart rate is for the aerobic zone somewhere on the web. I got mine from my nordic track manual. Also, if you really what to lose the fat, don't eat any carbs prior to cardio, best to do it in the morning when your glycogen stores are low so it forces your body to burn something other than sugar, fat we hope. To help combat it using muscle for fuel, I use glutamine and will sometimes have a protein drink prior. This will help preserve the muscle while burning the fat. Hope this helps.

Train hard or go home

 

[JB3]

I'm sorry, but there's no such thing as an "anaerobic zone." Truely anaerobic feats last <45 seconds, depending on adaptation. This is why the 400m is the longest "sprint." Exceeding this amount of time in a pure sprint is approaching impossible because of the fuel required. (You use no oxygen.) However, anything lasting over a minute is aerobic in nature, at least to a great extent, so ANY continuous cardio lasting more than a minute is largely aerobic.

Are you telling me that 30 minutes of intervals (run/jog) is purely anaerobic in nature? Well, that's completely false. We do not have the capacity.

True, exercise under roughly 65% of MHR is almost entirely aerobic (Lyle McDonald), but a completely aerobic exercise does not have to be the goal. Burning calories is our goal, and that's all that matters. If you burn more than you eat you'll lose weight. I don't understand where all this "you MUST do slow-as-hell cardio to lose fat" crap came from but it's total bull.

Glycogen is required to burn fat. Have you heard of "the wall" that long-distance runners hit? They experience a drastic decrease in performance once glycogen has been depleted. You cannot run on fat alone.

WarLobo, yes, energy expenditure is exponential with speed! That's exactly my point. If I run twice as fast as you're walking, I'm burning more than twice the amount of calories = EFFICIENCY. I'll also burn more calories AFTER exercise because of an increased metabolism AND have a raised metabolism for a longer period of time.

If speed is catabolic, blah, blah, blah... tell me why Olympic sprinters (drug tested) have such a low bodyfat with a high amount of muscle???

 

[MS]

Rather than use terms like "aerobic" and "anaerobic", it is more meaninful to talk in terms of % energy that comes from fat oxidation versus glycolysis or gluconeogenesis. When we look at exercize this way we see that doing nothing burns the highest %fat, and a flat out sprint burns the lowest %fat. So yes, sprinting burns more calories (and more fat), but backing off the pace a tad will increase the %fat burned when doing cardio (though less energy overall). Liver glycogen and blood glucose levels also affect the %fat burned, and a protein drink can affect both of these and slow the depletion of liver glycogen. This is not to say that sprinting is no good for fat loss, or that protein will make you fat! It really depends on your goals.

As far as metabolism boosts from cardio, this is one area where men and women may be very different. In men, maintaining aerobic fitness seems to burn calories WHILE exercizing, but may not have any post exercize metabolic benefits:

Effects of Aerobic Fitness on Fat Oxidation and Body Fatness.

For years, it has been debated as to whether aerobic exercise and high aerobic fitness can actually increase resting (non-exercise) metabolic rate or whether it simply burns calories only while you're doing the exercise.   It is well known that resistance exercise not only burns calories during the exercise bout but that it increases metabolic
rate for 24-48 hours after the exercise bout.  This information has tremendous impact on body composition and fatness. This study was designed to examine the relationships between fat breakdown (oxidation), aerobic fitness, and body fatness.  49 male and 45 female adults were evaluated based on their aerobic fitness levels (VO2 max), body fat levels (underwater weighing), resting metabolic rate and fat breakdown (metabolic cart), and 24-hour energy expenditure
(whole room indirect calorimeter).  Before testing, subjects abstained from exercise for at least 36 hours so that true resting measures of fat breakdown, metabolic rate, and 24-hour energy expenditure were not influenced by the previous exercise bout.  The authors speculated that daily fat breakdown is regulated by fat mass, physical activity, and fitness. Results:
1) On non-exercise days, males with higher aerobic fitness scores broke down less fat than those who had lower aerobic fitness scores.  This was not true in women.
2) There was no relationship between 24-hour energy expenditure on non-exercise days and fitness scores for men or women.  This means that fitter individuals do not burn more calories on non-exercise days than those who are less fit.
3) Males with more body fat had higher rates of fat breakdown than those with less body fat.  This was not true in women.
4) Fat free mass did not correlate well with fat breakdown for men or women so it appears that muscle mass does not regulate fat breakdown very well.

(A. Kriketos, et al. Med Sci Sports Exerc, 32(4): 805-811,
2000.)

 

[Cheetarah]

Okay, sorry, I have obviously misled people with my explanation, let me try it again. I know that the body cannot sustain a purely anaerobic activity for very long at all which is why you get cramps with the buildup of lactic acid being a byproduct of the reaction without oxygen. But there is a point at which your body will start performing BOTH reactions i.e. with and without the oxygen and for most people it is usually at about 80% of their maximum capacity which correlates directly to heart rate. That is the point when the body starts falling short of being able to provide enough oxygen for the rapidly contracting muscles. So you burn a higher percentage of BF at moderate levels of intensity since all the metabolic reactions are with oxygen, but at the same time, you do burn more calories overall at a higher intensity which can still mean more fat is burned. The whole trick is to try and get your body to burn the fat instead of the glucose and glycogen. So you don't want to carb up before the activity.

Not sure what you mean by needing glycogen to burn fat, glycogen is just the storage form of sugars in your muscles. Not sure how that plays into fat burning, explain please? Definitely a decrease in performance once glycogen is used up, being a speedskater, I can attest to that.

Ever notice the body composition of sprinters as compared to long distance runners? I think all the long distance runners I've seen are skinny, most likely because they burn up all the glycogen in their systems then their bodies burn off the fat and muscle.

I just love this stuff, biology, physiology, fitness, nutrition, always thirsting to learn more!

TRAIN HARD OR GO HOME

 

[JB3]

MS,


"Fitter individuals do not burn more calories on non-workout days than non-fit individuals" ? Excuse me? I guess it depends on the definition of "fitter," but having a higher muscle mass will most definately burn more calories on non-work days, so I'm not sure what this means. Are you saying that these fit and non-fit individuals had the exact same amount of LBM? Somehow I doubt that. Fitter people have a higher BMR... but maybe I'm misreading.

Cheetarah,

I don't know the exact physiology yet (I'm starting Grad School this fall so ask me in a year, heh), but glycogen IS required to burn fat. You mentioned that you know about "The Wall." Well, this is the point at which glycogen store become depleted, resulting in a drastic drecrease in performance. This is because you cannot burn fat alone for energy (during exercise). SOME glycogen is required. The amount of which is dependant upon the intensity of the activity, as MS mentioned.

My point is this... Calories are calories, and you burn more calories (exponentially so) the faster you jog/run. Running @ 8 mph for 30 min burns more calories than walking @ 4 mph for an hour. And you will burn more calories post-exercise because of the intensity of the activity. This makes jogging/running much more efficient than walking.

Yes, long distance runners are skinny, but a heavy fart could blow them over (they have no muscle). I assume this is not the look you're trying to attain. Sprinters are very lean AND have a high proportion of muscle. This is the look I'm going for.

I'm experimenting with pre-cardio carbs/protein and have yet to find the perfect amount/ratio. All I know is that my lactate threshold is MUCH higher during cardio if I have SOME carbs in me. Without any carbs, lactate pools much more quickly causing side aches. Normally, I'll never get cramps, but I do if I don't eat anything. If I feel better and my workout is much more productive, tell me why eating 25g of carbs and protein before cardio is hurting me? Those extra 100 calories (from carbs) are most definately being burned off by the extra effort I'm able to put forth.

Just my experiences, y'all.

 

[Cheetarah]

I'm going for the sprinter's look also. I've experienced the same exact thing when doing cardio, the more carbs (simple and complex) I have in me, the better I perform. I am able to perform at a higher intensity for longer periods. That's why I always carb up before my speedskating practices, I last much longer that way. I've recently cut way down on my carb intake (on non-speedskating days, since I don't want my speedskating to suffer) and I have noticed something. For the last couple days I have noticed that after about 35 min of steady, moderate intensity, same resistance, on my nordic track, my heart rate suddenly goes up about 10 beats per minute and the same resistance feels harder and my muscles feel tired. I was wondering to myself if it is because I have depleted most of my glycogen and my body has kicked into burning other fuel, which is what I'm hoping. I have never noticed it before when I know I had carbs in my system. I don't cramp up or anything, just my heart rate goes up and my muscles tighten up. This has been when I haven't had any carbs prior. I'm wondering if the body has to kick into a higher gear to burn something other than glucose since glucose is the easiest for it to break down. Any thoughts on this?