Will adding 20 minutes of HIIT to weight slow my growth?

[buzz]

WRANGELL
ss-cardio below 70% hr will not utilise sugars/carbs HIIT will,so if after a heavy weights session your body releases cortisol doing another anearobic exercise will most likely use up muscle.
also as you have already taken advantage of EPOC due to the weights why take a chance of using up muscle.
as i have said IMO i would do cardio on a sepperate day altogether if possible,and i doubt doing HIIT on non weight days will have any chance of releasing any cortisol,because HIIT is very short "if its not then its not HIIT".

but if you have to do cardio after weights then IMO ss-cardio is a better bet.

as you pointed out bipenate is infact correct that diet can alter when cortisol is released.but it is a difficult thing to judge,i would rather do a shorter workout than take the chance of wasting a lot of time in the gym and ending up with less than optimum results.

also another point, some studies have shown that the more conditioned you are ie the longer you have trained,the longer it may take before you release cortisol.

here is a study showing bipenates point,but as i said even though i take carbs before i dnever do more than an hour weights.

hope that answers your question


Liquid carbohydrate/essential amino acid ingestion during a short-term bout of resistance exercise suppresses myofibrillar protein degradation.Bird SP, Tarpenning KM, Marino FE.
School of Human Movement Studies, Charles Sturt University, Bathurst, NSW 2795, Australia.

A number of physiological events including the level of contractile activity, nutrient status, and hormonal action influence the magnitude of exercise-induced skeletal muscle growth. However, it is not the independent action of a single mechanism, but the complex interaction between events that enhance the long-term adaptations to resistance training. The purpose of the present investigation was to examine the influence of liquid carbohydrate (CHO) and essential amino acid (EAA) ingestion during resistance exercise and modification of the immediate hormonal response on myofibrillar protein degradation as assessed by 3-methylhistidine (3-MH) excretion. After a 4-hour fast, 32 untrained young men (18-29 years) performed a single bout of resistance exercise (complete body; 3 setsx10 repetitions at 75% of 1-repetition maximum; 1-minute rest between sets), during which they consumed a 6% CHO (n=8) solution, a 6-g EAA (n=8) mixture, a combined CHO+EAA (n=8) supplement, or placebo (PLA; n=8) beverage. Resistance exercise performed in conjunction with CHO and CHO+EAA ingestion resulted in significantly elevated (P<.001) glucose and insulin concentrations above baseline, whereas EAA ingestion only increased the postexercise insulin response (P<.05). Time matched at 60 minutes, the PLA group exhibited a peak cortisol increase of 105% (P<.001) with no significant change in glucose or insulin concentrations. Conversely, the CHO and CHO+EAA groups displayed a decrease in cortisol levels of 11% and 7%, respectively. Coinciding with these hormonal response patterns were significant differences in myofibrillar protein degradation. Ingestion of the EAA and CHO treatments attenuated 3-MH excretion 48 hours after the exercise bout. Moreover, this response was synergistically potentiated when the 2 treatments were combined, with CHO+EAA ingestion resulting in a 27% reduction (P<.01) in 3-MH excretion. In contrast, the PLA group displayed a 56% increase (P<.01) in 3-MH excretion. These data demonstrate that not only does CHO and EAA ingestion during the exercise bout suppress exercise-induced cortisol release; the stimulatory effect of resistance exercise on myofibrillar protein degradation can be attenuated, most dramatically when the treatments are combined (CHO+EAA). Through an "anticatabolic effect," this altered balance may better favor the conservation of myofibrillar protein.

PMID: 16631431 [PubMed - indexed for MEDLINE

 

[Wrangell]

WRANGELL
ss-cardio below 70% hr will not utilise sugars/carbs .....HIIT will

Why ' not ' ?

My understanding is that about 70% - 75% MHR your body is using about 50% carbs AND 50% fat. You are always using some amount of carbs during aerobic cardio...it simply varies with intensity.

Even in the mid 60%+ MHR, you are still burning 40% or so from carbs...just a bigger amount from fat - i.e 60%. Ditto for 85% MHR - you're using much much less fat, but some is still being burned.

Besides, what does this have to do with cortisol, HIIT and muscle loss ?

so if after a heavy weights session your body releases cortisol doing another anearobic exercise will most likely use up muscle.

But why ? Why does having more cortisol around trigger anearobic exercise to use muscle as fuel ?

Even though HIIT uses a combo of glycogen ( the much higher percentage ) and fat, the depletion of your glycogen and fat energy stores during a weight workout shouldn't be substantial enough ( during most ' normal ' weight workouts ) to trigger your body turn to muscle for fuel due to a lack of energy. So, the issue must be coitisol and muscle loss.

That said, are you saying that HIIT - in and of itself - triggers cortisol ? And, that the cumulative effect of weight training induced cortisol and HIIT cortisol enhances muscle loss ?

also as you have already taken advantage of EPOC due to the weights why take a chance of using up muscle./QUOTE]

Not sure I follow - are you saying EPOC burns muscle ?

as i have said IMO i would do cardio on a sepperate day altogether if possible,and i doubt doing HIIT on non weight days will have any chance of releasing any cortisol,because HIIT is very short "if its not then its not HIIT".

I always thought cortisol was triggered due to some ' stress ' stimulus.

So a 45 - 1 hour weight session will trigger a significant enough release of cortisol - enough to possibly promote muscle as fuel. The ' stress ' of lifting weights will trigger the cortisol.

But, doing 30 minutes of flat-out hard HIIT is not stressful enough to trigger cortisol ? I've done both - weights and HIIT - and HIIT always is as ( if not a lot more ) stressful than my weight sessions ! Why is it HIIT is not stressful enough to release cortisol in your view ?

but if you have to do cardio after weights then IMO ss-cardio is a better bet.

Well, if HIIT doesn't trigger any further cortisol ( as you say ), and ss cardio also doesn't trigger any further cortisol and both have adequate fuel stores to use ( i.e carbs and fat ) there shouldn't be any greater risk if your use HIIT or ss cardio after weights- should there ? What's the difference ?

as you pointed out bipenate is infact correct that diet can alter when cortisol is released.but it is a difficult thing to judge,i would rather do a shorter workout than take the chance of wasting a lot of time in the gym and ending up with less than optimum results.

I think his point was, that assuming proper nutrition, cortisol is a non-issue.

 

[Karky]

the difference is that HIIT is so darn intense, that you will puke.
All exercise has a chanse of causing you to burn protein and muscle if your nutrition is off (or the session is too long). Generally, the body will start using protein/muscle for fuel, usually after pretty long exercise. A good warning sign is that you start to smell ammonia. Something that smells that way is left after some protein or ammino accid (i cant remember this completley) has been broken down, and it has to be taken out of your body through your sweat.

 

[buzz]

wrangell
Why ' not ' ?

My understanding is that about 70% - 75% MHR your body is using about 50% carbs AND 50% fat. You are always using some amount of carbs during aerobic cardio...it simply varies with intensity.
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60% to 70% zone doesnt use carbs read below recovery zone
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wrangell

But why ? Why does having more cortisol around trigger anearobic exercise to use muscle as fuel ?
........................................................................................................

read below anearobic zone.
your body releases cortisol because its run out of glucose/glycogen/sugars/etc the aerobic zone uses all of these so the energy the body needs will come from the protein you need for muscle growth
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wrangell
I always thought cortisol was triggered due to some ' stress ' stimulus.

So a 45 - 1 hour weight session will trigger a significant enough release of cortisol - enough to possibly promote muscle as fuel. The ' stress ' of lifting weights will trigger the cortisol.

But, doing 30 minutes of flat-out hard HIIT is not stressful enough to trigger cortisol ? I've done both - weights and HIIT - and HIIT always is as ( if not a lot more ) stressful than my weight sessions ! Why is it HIIT is not stressful enough to release cortisol in your view ?

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stress,depression.diet,time of day,all effect cortisol.
if your pre fuelled its most likely your body may take longer to release cortisol,but that depends how long and how intense your weights are IMO doing squats with 200k on my back is a lot more intense than HIIT.so doing 30mins HIIT will not be long enough to release cortisol IF PREFUELLED but doing a 45min weight session which is anearobic then 30 mins HIIT which is also anearobic IMO is to much of a risk.

also HIIT should be done at near maximum intensity 100m 200m sprints etc,if your doing 30mins are you really doing HIIT or just interval training
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wrangell
I think his point was, that assuming proper nutrition, cortisol is a non-issue.
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it could be a non issue with a normal workout,but if your going to be doing 2x hrs at a high intensity i wouldnt want to take the chance of wasting hard earned muscle
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wrangell
Not sure I follow - are you saying EPOC burns muscle ?
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weights and HIIT both use EPOC one of the main effects of EPOC is it speeds up your metabolism after training,how does it do that, by repairing muscle tissue that has been torn down by weights and HIIT ,so effectively EPOC is the result of muscle teardown.
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Heart Rate Training Zones
Heart rate training zones are calculated by taking into consideration your Maximum Heart Rate (MHR) and your Resting Heart Rate (RHR). Within each training zone, subtle physiological effects take place to enhance your fitness.

The Energy Efficient or Recovery Zone - 60% to 70%
Training within this zone develops basic endurance and aerobic capacity. All easy recovery running should be completed at a maximum of 70%. Another advantage to running in this zone is that while you are happily fat burning you may lose weight and you will be allowing your muscles to re-energise with glycogen, which has been expended during those faster paced workouts. Check out the Fat burning zone page.


The Aerobic Zone - 70% to 80%
Training in this zone will develop your cardiovascular system. The body's ability to transport oxygen to, and carbon dioxide away from, the working muscles can be developed and improved. As you become fitter and stronger from training in this zone it will be possible to run some of your long weekend runs at up to 75%, so getting the benefits of some fat burning and improved aerobic capacity.

The Anaerobic Zone - 80% to 90%
Training in this zone will develop your lactic acid system. In this zone, your individual anaerobic threshold is found - sometimes referred to the point of deflection (POD). During these heart rates, the amount of fat being utilised as the main source of energy is greatly reduced and glycogen stored in the muscle is predominantly used. One of the by-products of burning this glycogen is lactic acid. There is a point at which the body can no longer remove the lactic acid from the working muscles quickly enough. This is your anaerobic threshold or POD. Through the correct training, it is possible to delay the POD by being able to increase your ability to deal with the lactic acid for a longer period of time or by pushing the POD higher.

The Red Line Zone 90% to 100%
Training in this zone will only be possible for short periods. It effectively trains your fast twitch muscle fibres and helps to develop speed. This zone is reserved for interval running and only the very fit are able to train effectively within this zone.

if you still want to do weights and HIIT its up to you

 

[buzz]

Glucocorticoids (Cortisol). Glucocorticoids are released from the adrenal cortex in response to exercise stress. Unlike testosterone and hGH, they are catabolic. Cortisol is 95% of the glucocorticoids produced in the body. In peripheral tissues, cortisol stimulates lipolysis in adipose cells, increases protein degradation resulting in greater release of lipids, and decreases protein synthesis in muscle cells also releasing amino acids into the circulation (p. 348-349).

If an athlete used anabolic steroids, those steroids would reduce cortisol secretion during and after intense resistance exercise. Carbohydrate supplementation also reduces its secretion. A reduction in cortisol presence should result in an increase in the growth response from exercise. Once again, only highly demanding resistance training provokes an elevated cortisol response. The higher the demand, the greater is the response.MODERATE TRAINING HAS NO EFFECT.
from here

 

[bipennate]

Heart Rate Training Zones

Training according to heart rate zones is a myth that has been disproven in the literature...if it was true, HIIT would have little/no effect on fat loss. Overall caloric expenditure is what effects total fat loss, either through diet, exercise, EPOC, or any combination of them.

 

[Wrangell]

wrangell
Why ' not ' ?

My understanding is that about 70% - 75% MHR your body is using about 50% carbs AND 50% fat. You are always using some amount of carbs during aerobic cardio...it simply varies with intensity.
........................................................................................................
60% to 70% zone doesnt use carbs read below recovery zone
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You have said ...

" ss-cardio below 70% hr will not utilise sugars/carbs "

" 60% to 70% zone doesnt use carbs read below recovery zone "
​

.....I'm getting a bit confused as to what you're trying to say. I'm sure it's just me.

My understanding is that even when you're sitting doing nothing ( i.e rest ) your muscles burn both types of fuel at the same time - both fat & sugar. And if I recall correctly, that while at rest the bulk of this fuel is made up of fat - comprising about 70% or so - with carbs / sugar making up the bulk of the remaining 30%.

You say low MHR " doesn't use carbs " & " will not utilise sugars/carbs " - I assume you mean a ' lower percentage ' of carbs and NOT virtually ' 0 ' carbs at sub 60% MHR ?

You aren't suggesting that at these lower MHR we are using virtually 100% fat and virtually 0% carbs below 60% are you ? Because that's what your comments appear to be suggesting - at least to me.

What would say your best guess be of the % of energy that comes from fat at - for example - say 55 % of MHR ? Something close to 50%, 60%, 75%, 90% or 100% from fat ?


btw - could you please paste in the link where you got all your ' heart rate zone ' descriptions - thnks.

 

[Wrangell]

Glucocorticoids (Cortisol). Glucocorticoids are released from the adrenal cortex in response to exercise stress. Unlike testosterone and hGH, they are catabolic. Cortisol is 95% of the glucocorticoids produced in the body. In peripheral tissues, cortisol stimulates lipolysis in adipose cells, increases protein degradation resulting in greater release of lipids, and decreases protein synthesis in muscle cells also releasing amino acids into the circulation (p. 348-349).

If an athlete used anabolic steroids, those steroids would reduce cortisol secretion during and after intense resistance exercise. Carbohydrate supplementation also reduces its secretion. A reduction in cortisol presence should result in an increase in the growth response from exercise. Once again, only highly demanding resistance training provokes an elevated cortisol response. The higher the demand, the greater is the response.MODERATE TRAINING HAS NO EFFECT.
from here

No sure the point of this....we all have said we agree that weight training may result in higher levels of cortisol.

You have said it is best not to do HIIT after weight training - but it is better to do HIIT on it's own - due to the higher cortisol levels associated with some weight training - that IS your argument isn't it ?

 

[Wrangell]

wrangell

But why ? Why does having more cortisol around trigger anearobic exercise to use muscle as fuel ?
........................................................................................................

read below anearobic zone.

your body releases cortisol because its run out of glucose/glycogen/sugars/etc

the aerobic zone uses all of these so the energy the body needs will come from the protein you need for muscle growth
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When you say " your body releases cortisol because its run out of glucose/glycogen/sugars/etc " I assume you aren't saying 45 minutes to 1 hour of anaerobic weight training causes your body to ' run out ' of these carb based energy sources - thus stimulating the release of cortisol ?

Again, assuming adequate daily ' pre & post ' fuelling ' before training, most average gym rats have enough glycogen / glucose in their muscles, liver and blood to supply about 1,800 calories of carb based energy alone for weight training - in addition to any fuel for training that comes from fat.

Let's say the average gym rat does weights for 1 hour. You can't go at 95%+ MHR for a solid hour so lifting weights so your fuel consumption isn't coming 100% from glycogen / glucose but rather from both fat and glycogen. So, I don't think a complete depletion of glycogen / glucose stores is what would trigger cortisol and thus muscle to be sourced as fuel during 1 hour of weight training.

However, it sounds like your are saying that weight training for 1 hour followed by 30 minutes of HIIT will cause you to " run out of glucose/glycogen/sugars/etc " at some point during your HIIT - causing your HIIT session to then draw on muscle for fuel. Is that it ? So, assuming you only burn 80% of your total workout calories in 90 minutes from carb-based calories, are you saying you think it is possible to burn 2,300+-/ calories doing weight training and HIIT within 90 minutes ? Doesn't that seem like a lot ?

also HIIT should be done at near maximum intensity 100m 200m sprints etc,if your doing 30mins are you really doing HIIT or just interval training

HIIT is not the sole domain of metered distance sprints ( i.e 100m 200m sprints ) alone. But a function of a combination of high intensity heart rates / and varying time durations during work intervals and varying durations and intensities of rest intervals. Look at the landmark Tremblay study on the effect of HIIT & fat loss for example.

 

[buzz]

Training according to heart rate zones is a myth that has been disproven in the literature...if it was true, HIIT would have little/no effect on fat loss. Overall caloric expenditure is what effects total fat loss, either through diet, exercise, EPOC, or any combination of them.

i know heartrate training on its own is a myth ie, if i trained in the fatburn zone 60%hr i would burn fat during exercise,but the total cals would be minimal,so what i ate later in the day would most likely negate the exercise.

that was not my point or what i am trying to say,you can use your heartrate to figure out if your using carbs or not,ie 60% your not in the carb burning zone,so if you do an intense weights session,which will use EPOC afterwards,then droping down to 60% heartrate afterwards for 30mins cardio,is safer for retaining muscle than doing another anearobic exercise like HIIT.

 

[bipennate]

i know heartrate training on its own is a myth ie, if i trained in the fatburn zone 60%hr i would burn fat during exercise,but the total cals would be minimal,so what i ate later in the day would most likely negate the exercise.

that was not my point or what i am trying to say,you can use your heartrate to figure out if your using carbs or not,ie 60% your not in the carb burning zone,so if you do an intense weights session,which will use EPOC afterwards,then droping down to 60% heartrate afterwards for 30mins cardio,is safer for retaining muscle than doing another anearobic exercise like HIIT.

That's what you're misunderstanding, Buzz: you can't use "zones" like that. HR reserve, estimated max HR, etc, etc, are all estimated levels based on general population scores. The only way to truly know your Max HR (and base numbers of of that) is with stress tests. And even if you get that, claiming that you're using carbs at this % of your Max HR or fat at that % of your Max HR doesn't work, either: your body uses all energy symptoms (phosphogens/creatine phosphate, aerobic & anaerobic glycolysis/lactic acid, oxidative/lipolysis) at all times. It is never just one (physiology doesn't work that way). What happens is, depending on intensity of work (and hence the speed at which energy is needed), one/more system will be supplying a greater % of energy than the other systems, but never to the exclusion of the others, which means that no one substrate will be used at the exclusion of any other. That means whether you are laying on the couch asleep or running a 100 meter sprint, you are using carbs, fats, and even a small percentage of proteins for energy. You can't determine what is being used by your HR: it's far more complicated than that.

Also, you don't use EPOC after weight training, you cause EPOC from weight training.

 

[buzz]

BIP
i understand what your saying,and i know you dont stop using carbs altogether,but if your at a heartrate of 60% you will be using minimal carbs compared to mhr of 95%.
so as the op asked should he do HIIT after weights,i said no if he had to do cardio after weights (i prefer non weight days) to do ss-cardio at a low mhr,that way there is less chance of wasting muscle.

Also, you don't use EPOC after weight training, you cause EPOC from weight training.
i know this i just worded it wrong.

 

[Wrangell]

BIP
i understand what your saying,and i know you dont stop using carbs altogether,but if your at a heartrate of 60% you will be using minimal carbs compared to mhr of 95%.

Although at a HIIT session of 30 minutes, assuming you can sustain a work interval of 95% MHR for 1 minute ( assuming a 2 minute recovery ) - you may only be at a sustained 95% MHR for 10 minutes or so. So, you're not maximizing the burning of carbs during the entire session. But I suspect you're right , even though you may only be burning 30% - 40 % of total fuel from carbs at 60% MHR, you could be burning twice that proportion ( or more ) at 95% MHR.

so as the op asked should he do HIIT after weights,i said no if he had to do cardio after weights (i prefer non weight days) to do ss-cardio at a low mhr,that way there is less chance of wasting muscle.

Also, you don't use EPOC after weight training, you cause EPOC from weight training.
i know this i just worded it wrong.

Again,if you pre-fuel properly and all your glycogen stores a ' topped up ' before you train, I don't think 1 hour of weight training along with a post workout of 30 minutes of HIIT is going to exhaust your carb based stores so that such an occurrence ( i.e exhausting your carb stores ) is going to result in an enhanced chance of " wasting muscle ".

 

[Aetom]

Again,if you pre-fuel properly and all your glycogen stores a ' topped up ' before you train, I don't think 1 hour of weight training along with a post workout of 30 minutes of HIIT is going to exhaust your carb based stores so that such an occurrence ( i.e exhausting your carb stores ) is going to result in an enhanced chance of " wasting muscle ".

Properly fueled, as in small meal an hour before HIIT with carbs and protein?
I thought you were supposed to take carbs and protein after HIIT.

 

[Wrangell]

Properly fueled, as in small meal an hour before HIIT with carbs and protein?

I thought you were supposed to take carbs and protein after HIIT.

Actually, when I said " pre-fuel properly and all your glycogen stores are ' topped up ' before you train " by " pre-fuel properly " I really meant making sure all your glycogen stores were topped up prior to any exercise due to proper daily/weekly nutrition - and not so much due to immediate pre-exercise nutrition.

Given it can take just under 24 hours or so to replentish significantly depleted glycogen stores, you want to make sure you engage ' all day fueling ' all week long to allow yourself enough time to refuel properly over the course of a week. By that I mean, simply eat a clean diet every day, eating meals / snacks every 2.5 - 3 hours ( if you can ) with the bulk of your calories coming from carbs ( i.e to help replace glycogen ). Doing this ' all day fueling ' on a daily basis each week will help ensure you have enough time to create the adequate glycogen stores you need as the primary fuel for anaerobic workouts like weight training and HIIT cardio. That would also include meals / snacks that make up your pre and post workout nutrition.