Cardio after 45 minutes?

[GinaMarie1143]

I was asked the question tonight..."Isnt a cardio workout worth nothing after 45 minutes?" I never heard this - At least not at 45 minutes....a trainer told this person that her body will not burn anything after 45 minutes of cardio - someone please give me the right science behind why a trainer would say this!

 

[P-funk]

You will burn nothing after 45min?

That trainer sounds like a really smart fellow.

 

[GinaMarie1143]

I told her I thought that was one of the craziest things Ive ever heard. I was recently certified by NASM myself and I questioned myself after hearing that. I told her I'd come on here and see what you guys could give me for back up on this subject - but I thought that was completely rediculous that he would tell her that...

 

[P-funk]

How could you continue doing work if you burned nothing after 45 min? Energy has to come from some where! How do people run marathons? How do people handle 2hr practices?

Your muscles need to produce tension to complete the task. For that you need energy.

That is the stupidest concept I have ever heard! lol

 

[GinaMarie1143]

Personally I am training for 2 marathons right now - and thats what I brought up to her. We did a 3 hour run last week and Id be an idiot to say I stopped burning carloies after the first 45 minutes. Ive heard before people make mention of "you dont burn quite as much" but I just could not accept hearing that your body becomes too acustomed to the exercise and that any exercise over 45 minutes was useless. I dont know that I even agree with the fact that you wont burn quite as much - because as the time increases usually the intensity increases becuase your body is working harder to continue the training...Thank you for your in put in helping me gain my sanity back!

 

[mike456]

lol, were does he think you will get the energy from , maybe he meant cardio over 45minutes is not optimal for fat burning?

 

[CowPimp]

lol, were does he think you will get the energy from , maybe he meant cardio over 45minutes is not optimal for fat burning?

Actually, as you continue doing cardio the primary energy substrate shifts even more toward fat usage.

 

[mike456]

Actually, as you continue doing cardio the primary energy substrate shifts even more toward fat usage.

that is the pro, is there a con?

 

[Double D]

Actually, as you continue doing cardio the primary energy substrate shifts even more toward fat usage.

Or breaking down of muscle, whichever....

 

[CowPimp]

Or breaking down of muscle, whichever....

I think that's overrated unless you are malnourished going into the workout and you perform a higher intensity workout that requires anaerobic metabolism to take place.

 

[CowPimp]

that is the pro, is there a con?

Yeah, it's a waste of fucking time unless you are training to compete in some type of long distance running competition.

 

[mike456]

Yeah, it's a waste of fucking time unless you are training to compete in some type of long distance running competition.

you just said longer the cardio, the more it shifts to using even more fat, how is that a waste of time

 

[Double D]

I think that's overrated unless you are malnourished going into the workout and you perform a higher intensity workout that requires anaerobic metabolism to take place.

Which the majority of people are. There are very few people who go into a workout and did the things they shouldve before they went.

 

[AKIRA]

Or breaking down of muscle, whichever....

Thats the only downfall I can see happening..

But Cow, if one isnt "malnourished," then longer cardio sessions wont break down proteins? Thats kind of a given, but whats border line malnourished?

 

[Double D]

I can see what you are saying CP if going in and done all the right things then ok. I can see your point, but like I said most are not.

 

[P-funk]

you just said longer the cardio, the more it shifts to using even more fat, how is that a waste of time

Simple:

The most important thing is to BURN CALORIES.


That said, if you were to walk for a real long time at a slow pace (it has to be slow to be able to go for a long time....remeber, as duration increases, intensity decreases), you will burn a greater percentage of calories from fat.

Now, if we shortened the duration but increased the intensity, we would burn less of a percentage of total calories form fat; but, you are burning a greater number of calories. So, because the total energy expenditure at the higher work rate is greater, the overal amount of fat mobilized will be higher.

 

[AKIRA]

Simple:

The most important thing is to BURN CALORIES.


That said, if you were to walk for a real long time at a slow pace (it has to be slow to be able to go for a long time....remeber, as duration increases, intensity decreases), you will burn a greater percentage of calories from fat.

Now, if we shortened the duration but increased the intensity, we would burn less of a percentage of total calories form fat; but, you are burning a greater number of calories. So, because the total energy expenditure at the higher work rate is greater, the overal amount of fat mobilized will be higher.

So, what would be more beneficial in losing weight?

 

[Double D]

My guess would be something as in the form of HIIT.

 

[P-funk]

So, what would be more beneficial in losing weight?

Both types are beneficial:

1) HIIT cardio = high rate of energy expenditure, high rate of oxygen debt, high rate of lactic acid (which is used as a signal of GH release), higher amounts of catecholamine release (epinephrine and norepinephrine).

2) Steady State cardio = increases in oxidative enzymes, increases in mitochondrial density, increases in mitochondrial surface area, increases in efficiency to burn fat as fuel, gives the CNS and muscle a break from high amounts of stimulation but still allows you to go and do some form of exercise and increase weekly net caloric expenditure.

 

[Double D]

But P if you are trying to lose weight and maintain muscle wouldnt hiit be best beings you arent eating as much and all the right nutrients and proteins and things like that arent there to back you up during a long cardio session?

 

[P-funk]

But P if you are trying to lose weight and maintain muscle wouldnt hiit be best beings you arent eating as much and all the right nutrients and proteins and things like that arent there to back you up during a long cardio session?

You aren't eating as much and you need to create a caloric defecit.

Eventually, you are going to get to parts in your diet where you can't lower calories anymore. It becomes a game of "how low can you go.". So, you have to create that defecit somehow. If anything, the HIIT cardio is going to be harder to perform because you are intaking less calories (usually in the form of less carbs) so you have less energy to output. But we still do it....why? Because we want to loose weight and something has to give! You have to burn calories some how.

 

[Double D]

Makes good sense to me.

 

[CowPimp]

Which the majority of people are. There are very few people who go into a workout and did the things they shouldve before they went.

Notice I said the following with that: "and you perform a higher intensity workout that requires anaerobic metabolism to take place."

Your body doesn't like to use protein as an energy source, and very little is used for energy unless you are talking really long cardio sessions that are like 90-120 minutes or more. At that point the glucose-alanine cycle starts to provide a bit more energy for the work at hand, but it is still a pretty small portion of total energy usage.

Anaerobic exercise is another scenario where muscle breakdown is more likely because of the need for glycogen/glucose to provide energy during the anaerobic portions of the exercise session. Deamination of protein and subsequent usage of the alphaketoacid for conversion to glucose in the liver may increase because of the very high energy demands of the exercise task and inadequacy of free fatty acids as an energy source.

Now, even if you don't go into a low-moderate intensity aerobic cardio session with sufficient blood glucose trickling in from your last meal, FFAs are going to provide the majority of the energy for the task at hand. The energy demands aren't great enough that your body is likely to catabolize a significant amount of muscle mass.

 

[Double D]

Good post CP....