T Nation

Three questions, would be grateful for some help

  1. (High) interval training. What advantages does this form for cardio have compared to ordinary 45-60 minutes of constanst heart-rate cardio? I know its much more efficent at increasing O2-uptake, which makes fat-burning easier.

  2. Morning cardio is promoted because of the metabolic state a person is in when waking up. However, on a low-carb diet, wont you get this effect at all times of the day, as the blood-sugar is steady low?

  3. Cheat-day, how much is TOO much? I know, I know, this is highly individual, but is there a sort of thumb-rule to follow not to totally over-do it? Im on T-Dawg, Ive had great progress when limiting it to one cheat-meal a week. Last saturday however, I went totally nuts, and Im wondering how harmful this moment of madness might have been.

Thanks,
SquatMan

Number One:

  1. More total calories burned. Although high-intensity aerobics will burn a little less fat than its moderate-intensity counterpart during the exercise session, the total number of calories (and fat) burned as a result of the former is substantially greater than that associated with the latter. This is due to an increased excess post-exercise oxygen consumption (EPOC). In other words, the number of calories burned during the hours following a high-intensity exercise bout is greatly increased due to a prolonged increase in oxygen consumption. With low to moderate intensity cardio, EPOC is minimal, thus metabolism quickly returns to baseline following the exercise session [6,7].

  2. Greater fat loss. In one particular study, individuals performed either an endurance training (ET) or HIIT training program for a period of 15-weeks. At the end of the testing period, the HIIT group experienced nine times the fat loss of the endurance training group [2]. This is certainly supported empirically by the many individuals who have experienced accelerated fat loss after adopting HIIT as their form of cardiovascular exercise.

  3. Greater increases in maximal oxygen intake and overall level of fitness. High-intensity interval training has proven to increase both one’s aerobic and anaerobic capacity; endurance training only increases the former [1,2,3,4]. Moreover, HIIT has been shown to increase one’s aerobic capacity even more so than endurance training [4]. One study showed a 14% increase in maximal oxygen uptake and a 28% increase in anaerobic capacity in only 14 weeks when following a high-intensity workout regimen [4].

Number Two:

Here is an excerpt from a recent article I composed:

I recommend conducting all cardiovascular activity in the morning to take advantage of the prolonged increase in metabolism. It is OK to have a small meal before your session as doing so improves performance and has a negligible impact on energy substrate utilization both during and after exercise [9,10,11,12]. As far as post workout nutrition is concerned, it is fine to go ahead and supplement with fast digesting proteins and carbohydrates immediately following your HIIT session. While the theory of waiting an hour before consuming a post workout meal/beverage sounded solid, it didn’t hold up when research put it to the test. Conversely, research shows that consuming quickly digested nutrients immediately following high intensity cardiovascular exercise actually increases EPOC, reduces muscle protein catabolism, and increases recovery, all while having no adverse effect on lipolysis (fat burning) [8].

Number Three:

This is a highly complicated question. A single meal isn’t going to yield much (if any) physiological benefit; it will only yield a psychological benefit. To get the physiological benefits (what you really need), the duration of the overfeed/refeed/cheat must be longer. The key is too keep carbs high and fat low to minimize the damage.

Take care,

Joel

OK, here’s my take on your questions:

  1. HIIT advantages:


    a) It stimulates anabolic vs catabolic hormonal responses in the body.


    b) It is actually more efficient in increasing POST-workout metabolic rate (great for fat-burning).


    c) It’s quick!


    d) It’s a challenge, and it actually feels like you’re doing something worthwhile! (Excuse me here if you’re that old guy I always see around our neighbourhood at 5am, with the old jogging suit, sweatband like J McEnroe, running for miles with a look of severe grimace :-))

  2. Have to agree, that morning cardio is probably overrated as a specific fat burning tool, especially if you are on the type of diet suggested. However the body MAY still be in more of a fat-burning mode before breaking the night fast, than at other times of the day when intake of calories is more frequent.

  3. Will let J Marion and other “experts” in the cheat meal (Timbo- d’ya want to chip in?) answer this one. You could also post on the thread of Timbo’s focused on this topic- it’s still current and around about the first few pages of the forum.


    However, you should remember that the purpose of the cheat meal is simply to restock the glycogen supplies within the muscle to a point where they can function efficiently again. How much is too much? Well, if your total calorie intake for the week (including cheat meals) is still hypocaloric, then you’re doing ok and will continue to lose weight (fat). That’s just my “simpleton’s” version.


    Hope this helps, SRS.

SRS said:

“However, you should remember that the purpose of the cheat meal is simply to restock the glycogen supplies within the muscle to a point where they can function efficiently again.”

This is one of the benefits, but it is not the major one. In fact, if this was the only benefit, I would never recommend periodic refeeding/overfeeding.

Yeah, the rationale for refeeding goes far beyond simply refilling muscle glycogen. It serves an important function in that it stabalizes and hopefully brings up your lower leptin levels during cutting cycles.

OK, Joel, thanks for pointing out that my “simply” statement was a little too simple! You are right that needs to be rephrased.


I should indeed have mentioned the fact that you are also aiming to kickstart your hormonal response back into fat burning mode. I guess I was just trying to explain what the cheat meal does, rather than what it stimulates into happening.


As Squatman’s main concern was taking in too much on cheat day, I was trying to remind him of what he is aiming to do on this day- basically refill the body with carbs.


SRS

While Joel did a great job answering your questions, I feel that his reply to number three was a bit short of the mark.

“How so?” you ask. Well, since you yourself are aware that refeeds are highly individual, and yet are wondering how your Saturday pig-fest is going to affect you…

How do you expect someone else to answer this for you? The only possible answer is: see for yourself. You are keeping decent BF records, right?

Sorry to sound like a dick here, but really.

I completely agree with char that you need to make the assessment for yourself. However, most people don’t have a clue as to the how’s and why’s of periodic overfeeding/refeeding/cheating. The approach needs to be highly strategic and you need to understand the physiology behind it. A question of “how much is too much?” is far too ambiguous to provide an answer to; there is a great deal to it. If you want some more information on this, send me an email. I can provide you with some information to get you started, but ultimately you’ll have to find out what works for you (better to start with some sound advice then to just wing it, though).

Joel