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Sinep
08-14-2003, 09:18 AM
So what is the bottom line on cardio ? I've heard some say that the benefit from cardio is that it fasten your metabolism. Others say the exercise itself burns fat. Some say don't take carbs before, some say do. Low or high intensity? So much controversy. Please respond only if you truly have a clue.

bradley
08-14-2003, 11:07 AM
It basically comes down to what type of cardio you are referring to. If you are referring to aerobic exercise at low intensities then the majority of the fuel will come from fat, but as you increase exercise intensity more energy will be derived from muscle glycogen.

Even though you will technically burn more calories performing longer duration low intensity cardio, does not necessarily mean that this is the best way to improve body composition. The study below is a good example.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8028502&dopt=Abstract

The excess post-exercise oxygen consumption (EPOC) will be greater for high intensity exercise as opposed to aerobic training which could offer one reason for the results seen in the study above.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2347316&dopt=Abstract

I do not think it is going to make that much of a difference as to whether you eat something before performing cardio, regardless of what type you are performing. Total calorie balance at the end of the day will be the main determining factor as to whether or not you lose weight, and by eating something before hand the chances of muscle catabolism would be decreased. If you were trying to prepare for a competition and needed to get rid of that last little bit of stubborn bf, then low intensity morning cardio might be of more benefit.

Incorporating both low and high intensity cardio would be the best approach IMO. While HIIT training is definitely a solid approach to fat loss, it also requires more recovery than low intensity cardio. The chances of overtraining would increase if you attempted too many HIIT sessions per week along with you weight training program.

There is obviously much more information on the topic than what I have provided above, but hopefully that will offer some insight.:)

Manveet
08-14-2003, 11:43 AM
One thing that I'm still unclear with is, where does cardio come into play when you are in the early stages of a cut? (like one week into a cut, coming off a several month bulk) Should cardio stay out for awhile and you should just concetrate on reducing cals? Or should you reduce less cals and add cardio early on into the cut?

I didn't want to hijack anyone's thread, but I didn't feel like starting another "cardio" thread.

raniali
08-14-2003, 12:33 PM
i view cardio as another variable in dieting. if your current calorie deficit is allowing you to lose 1-2 lbs/week, then the additional cardio is not necessary for wt loss. when cutting cals becomes more difficult (for fear of dropping too low), then adding some cardio can be the next weapon in the fight to lose fat. when some cardio is no longer effective, then change the type, duration and/or intensity.

Ironman8
08-14-2003, 12:37 PM
No one does cardio for health?

raniali
08-14-2003, 12:49 PM
yes - but that wasn't the question

bradley
08-14-2003, 01:46 PM
Originally posted by Manveet
One thing that I'm still unclear with is, where does cardio come into play when you are in the early stages of a cut? (like one week into a cut, coming off a several month bulk) Should cardio stay out for awhile and you should just concetrate on reducing cals? Or should you reduce less cals and add cardio early on into the cut?


Small amounts of HIIT training could be beneficial regardless of whether you are cutting or bulking.

HIIT cardio uses both anaerobic and aerobic metabolic pathways which would lead me to believe that you would see some of the same benefits from HIIT as you would from resistance training. Albeit I am sure to a lesser degree, and a couple of things that come to mind would be nutrient partitioning and the effect of anaerobic training on hormone levels in the body.

bradley
08-14-2003, 02:14 PM
Acute effect of brief low- and high-intensity exercise on circulating insulin-like growth factor (IGF) I, II, and IGF-binding protein-3 and its proteolysis in young healthy men.

Schwarz AJ, Brasel JA, Hintz RL, Mohan S, Cooper DM.

Department of Pediatrics, UCLA Medical Center, Torrance 90509, USA.

We measured circulating levels of the GH insulin-like growth factor (IGF) system in response to brief exercise of different intensities. Ten males (mean age 28 +/- 5 yr) were studied on three separate occasions: once under resting conditions (control) and once each performing 10 min of low- or high-intensity exercise. Blood samples were assayed by RIA for GH, IGF-I and -II, IGF-binding protein-3 (IGFBP-3), and IGFBP-3 proteolytic activity. After 10 min of low-intensity exercise, IGF-I and IGFBP-3 had increased over preexercise baseline by 7.7 +/- 2.7% (P < 0.05) and 12.5 +/- 3.3% (P < 0.004), respectively. After 10 min of high-intensity exercise, all measured components of the IGF system were increased: IGF-I by 13.3 +/- 3.2% (P < 0.002), IGF-II by 15.7 +/- 3.1 (P < 0.01), and IGFBP-3 by 23 +/- 6% (P < 0.001). IGFBP-3 proteolytic activity also was increased (44 +/- 14% above baseline, P < 0.05). GH reached its peak 10 min after the cessation of high-intensity exercise, unlike the earlier peaks of IGF-I and II. In summary: 1) brief exercise leads to small but significant increases in circulating IGF-I, IGF-II, IGFBP-3, and IGFBP-3 proteolysis; and 2) these responses may be influenced by exercise intensity. The IGF responses seem to be unrelated to GH. Acute exercise-induced proteolysis of IGFBP-3 may contribute to anabolic effects of physical activity by increasing the bioavailability of IGF-I.