[harmankardon1]

was just wondering the best times to do cardio? im at 15% and am going to go back into the single figures, but i dont want to sacrifice hard earned muscle, is doing light cardio (walking at brisk pace for 30-40min) in the mornings before i eat going to be okay? will it be harsh on muscle ??? at the moment i am doin 40 minutes walk 5-6 days a week a couple of hours before bed then just having 40 grams of isolate afterwards.

[harmankardon1]

thanks for any replies

[nmb1233]

i prefer after a workout...in the morning your body is in a fast state.....if your gonna do it in the morning take in some whey protein about 30 - 45 min before hand....

[chrispghmuscle]

I typically do it in the afternoon or evenings. Depends on my work schedule or daughter's nap time. lol

It will be for me tonight. If it doesn't rain I will run a 3 mile course I have set up in my hood..

If it does rain I jump on my eliptical machine for about and hour.

Both time I throw my mp3 player on and hit it.

I got a fresh wax job and put on my speedo and wave to the hot neighbors around my hood..( LMAO < I threw that in for my boy Moorey) sup bro.LOL..

[ibanezman88]

i do my 45 min. after the workout.

[harmankardon1]

so the morning on an empty somach could be a little detriemental on my gains

[ZiR RED]

1. Do high intensity interval training. ie: Sprint, just like the character on your avator.

2. Do not do faster cardio.

Below are two of my favorite articles on the subject by Alan Argon

Myths Under The Microscope Part 1: The Low Intensity Fat Burning Zone

By Alan Aragon © 2006




The “Fat Burning Zone” On Trial

Origin of the myth

Dietary variables aside, the body’s proportional use of fat for fuel during exercise is dependent upon training intensity. The lower the intensity, the greater the proportion of stored fat is used for fuel. The higher the intensity, the greater proportional use of glycogen and/or the phosphagen system. But this is where the misunderstanding begins. Although I’m burning a greater proportion of stored fat typing this sentence, getting up and sprinting would have a greater impact on fat reduction despite its lesser proportional use of fat to power the increased intensity. Alas, sufficient investigation of the intensity threshold of maximal net fat oxidation has been done. In what’s perhaps the best designed trial of its kind, Achten & Jeukendrup found peak fat oxidation to occur during exercise at 63% VO2 max. This peak level got progressively less beyond that point, and was minimal at 82% VO2 max, near the lactate threshold of 87% [1].

Misunderstanding is perpetuated in fitness circles

It has been widely misconstrued that a greater net amount of fat is burned through lower to moderate intensity work, regardless of study duration and endpoints assessed. In addition the confusion of net fat oxidation with proportional fat oxidation, the postexercise period is critically overlooked. No distinction is ever made between during-exercise fat oxidation, recovery period fat oxidation, total fat oxidation by the end of a 24-hr period, and most importantly, a longer term of several weeks.. Thus, the superiority of lower intensity cardio continues to be touted over the more rigorous stuff that takes half the time to do. Fortunately, we have enough research data to gain a clear understanding. Let’s dig in.


Dissecting The Research

Mixed study protocols + mixed results = plenty of mixed-up trainees

As with all research involving applied physiology, the highly mixed set of results is due to a wide variation of study designs in terms subject profile, dietary manipulation, energetic balance, and actual intensities used. Nevertheless, the body of exercise-induced fat oxidation research can be easily deciphered by stratifying it into 3 subgroups: Acute effect (during exercise & immediately after), 24-hr effect, & chronic effect (results over several weeks).

Acute effects spawn ideas for further research

In addition to measuring fat oxidation during exercise, most acute effect trials look at fat oxidation at the 3 to 6 hr mark postexercise [2]. Fat oxidation during exercise tends to be higher in low-intensity treatments, but postexercise fat oxidation tends to be higher in high-intensity treatments. For example, Phelain’s team compared fat oxidation in at 3hrs postexercise of 75% VO2 max versus the same kcals burned at 50% [3]. Fat oxidation was insignificantly higher during exercise for the 50% group, but was significantly higher for the 75% group 3 hours postexercise. Lee’s team compared, in college males, the thermogenic and lipolytic effects of exercise pre-fueled with milk + glucose on high versus low-intensity training [4]. Predictably, pre-exercise intake of the milk/glucose solution increased excess postexercise oxygen consumption (EPOC, aka residual thermogenesis) significantly more than the fasted control group in both cases. The high-intensity treatment had more fat oxidation during the recovery period than the low intensity treatment. This implicates pre-fueled high-intensity training’s potential role in optimizing fat reduction while simultaneously setting the stage for quicker recovery.

24-hr effects come closer to reality

You can call it Murphy’s Law, but the promise of greater fat oxidation seen during and in the early postexercise periods of lower intensity cardio disappears when the effects are measured over 24 hours. Melanson’s research team was perhaps the first to break the redundancy of studies that only compared effects within a few hours postexercise [5]. In a design involving an even mix of lean, healthy men & women aged 20-45, identical caloric expenditures of 40% VO2 max was compared with 70% VO2 max. Result? No difference in net fat oxidation between the low & high-intensity groups at the 24 hr mark.

Saris & Schrauwen conducted a similar study on obese males using a high-intensity interval protocol versus a low-intensity linear one [6]. There was no difference in fat oxidation between high & low intensity treatments at 24 hrs. In addition, the high-intensity group actually maintained a lower respiratory quotient in postexercise. This means that their fat oxidation was higher than the low-intensity group the rest of the day following the training bout, thus the evening out the end results at 24 hrs.

Chronic effects come even closer

Long-term/Chronic effect studies are the true tests of whatever hints and clues we might get from acute studies. The results of trials carried out over several weeks have obvious validity advantages over shorter ones. They also afford the opportunity to measure changes in body composition, versus mere substrate use proximal to exercise. The common thread running through these trials is that when caloric expenditure during exercise is matched, negligible fat loss differences are seen. The fact relevant to bodybuilding is that high-intensity groups either gain or maintain LBM, whereas the low-intensity groups tend to lose lean mass, hence the high intensity groups experience less net losses in weight [7-9].

The body of research strongly favors high-intensity interval training (HIIT) for both fat loss and lean mass gain/maintenance, even across a broad range of study populations [9-12]. A memorable example of this is work by Tremblay’s team, observing the effect of 20 weeks of HIIT versus endurance training (ET) on young adults [9]. When energy expenditure between groups was corrected, HIIT group showed a whopping 9 times the fat loss as the ET group. In the HIIT group, biopsies showed an increase of glycolytic enzymes, as well as an increase of 3-hydroxyacyl coenzyme A dehydrogenase (HADH) activity, a marker of fat oxidation. Researchers concluded that the metabolic adaptations in muscle in response to HIIT favor the process of fat oxidation. The mechanisms for these results are still under investigation, but they’re centered around residual thermic and lipolytic effects mediated by enzymatic, morphologic, and beta-adrenergic adaptations in muscle. Linear/steady state comparisons of the 2 types tends to find no difference, except for better cardiovascular fitness gains in the high-intensity groups [13].

Summing Up the Research Findings

• In acute trials, fat oxidation during exercise tends to be higher in low-intensity treatments, but postexercise fat oxidation and/or energy expenditure tends to be higher in high-intensity treatments.
• Fed subjects consistently experience a greater thermic effect postexercise in both intensity ranges.
• In 24-hr trials, there is no difference in fat oxidation between the 2 types, pointing to a delayed rise in fat oxidation in the high-intensity groups which evens out the field.
• In long-term studies, both linear high-intensity and HIIT training is superior to lower intensities on the whole for maintaining and/or increasing cardiovascular fitness & lean mass, and are at least as effective, and according to some research, far better at reducing bodyfat.





References

1.
Achten J, Jeukendrup AE. Relation between plasma lactate concentration and fat oxidation rates over a wide range of exercise intensities. Int J Sports Med. 2004 Jan;25(1):32-7.
2.
Thompson DL, et al. Substrate use during and following moderate- and low-intensity exercise: implications for weight control. Eur J Appl Physiol Occup Physiol. 1998 Jun;78(1):43-9.
3.
Phelain JF, et al. Postexercise energy expenditure and substrate oxidation in young women resulting from exercise bouts of different intensity.J Am Coll Nutr. 1997 Apr;16(2):140-6.
4.
Lee YS. Et al. The effects of various intensities and durations of exercise with and without glucose in milk ingestion on postexercise oxygen consumption. J Sports Med Phys Fitness. 1999 Dec;39(4):341-7.
5.
Melanson EL, et al. Effect of exercise intensity on 24-h energy expenditure and nutrient oxidation. J Appl Physiol. 2002 Mar;92(3):1045-52.
6.
Saris WH, Schrauwen P. Substrate oxidation differences between high- and low-intensity exercise are compensated over 24 hours in obese men. Int J Obes Relat Metab Disord. June; 28 (6): 759-65.
7.
Grediagin A, et al. Exercise intensity does not effect body composition change in untrained, moderately overfat women. J Am Diet Assoc. 1995 Jun;95(6):661-5.
8.
Mougios V, et al. Does the intensity of an exercise programme modulate body composition changes? Int J Sports Med. 2006 Mar;27(3):178-81.
9.
Okura T, et al. Effects of exercise intensity on physical fitness and risk factors for coronary heart disease. Obes Res. 2003 Sep;11(9):1131-9.
10.
Tremblay, et al. Impact of exercise intensity on body fatness and skeletal muscle metabolism. Metabolism. 1994 Jul;43(7):814-8.
11.
Yoshioka M, et al. Impact of high-intensity exercise on energy expenditure, lipid oxidation and body fatness. Int J Obes Relat Metab Disord. 2001 Mar;25(3):332-9.
12.
Broeder CE, et al. The effects of either high-intensity resistance or endurance training on resting metabolic rate. Am J Clin Nutr. 1992 Apr;55(4):802-10.
13.
Gutin B, et al. Effects of exercise intensity on cardiovascular fitness, total body composition, and visceral adiposity of obese adolescents. Am J Clin Nutr. 2002 May;75(5):818-26.

[ZiR RED]

Enjoy

Myths Under The Microscope Part 2: False Hopes for Fasted Cardio

By Alan Aragon © 2006



False Hopes

The bandwagon is lead by blind horses

Many trainees pigeonhole weight training as an activity exclusively for building muscle, and cardio exclusively for burning fat. On the contrary, weight training can yield very similar results to cardio of similar intensity when 24-hr energy expenditure and macronutrient oxidation is measured [1]. The obvious advantage of weight training is the higher potential for lean mass and strength gains. In the bodybuilding context, cardio should be viewed as merely an adjunctive training mode to further energy expenditure and cross-complement the adaptations specific to weight training. As far as cardio being absolutely necessary for cardiovascular health, well, that depends upon the overall volume and magnitude of your weight training - another topic for another time.

Chaos theory strikes again

On the surface, it seems logical to separate carbs from cardio if you want a maximal degree of fat oxidation to occur during training. But, there’s the underlying mistake - focusing on stored fuel usage during training instead of focusing on optimally partitioning exogenous fuel for maximal lipolytic effect around the clock. Put another way, it’s a better objective to coincide your carb intake with your day’s thermic peaks, where insulin sensitivity & lean tissue reception to carbs is highest. For some reason, this logic is not easily accepted, nor understood. As we know, human physiology doesn’t always cooperate with logic or popular opinion, so let’s scrutinize the science behind the claims.

Let The Research Speak

Carbohydrate ingestion during low-intensity exercise reduces fat oxidation

As far as 3 decades back, Ahlborg’s team observed that carb ingestion during low-intensity exercise (25-45% VO2 max) reduced fat oxidation compared to fasted levels [2]. More recently, De Glisezinski’s team observed similar results in trained men at 50% VO2 max [3]. Efforts to determine the mechanism behind this phenomenon have been made. Coyle’s team observed that at 50% VO2 max, carbohydrate availability can directly regulate fat oxidation by coordinating hyperinsulinemia to inhibit long-chain fatty acid transport into mitochondria [4].

Carbohydrate’s effect on fat oxidation during moderate-intensity exercise depends on conditioning level

Civitarese’s team found glucose ingestion during exercise to blunt lipolysis via decreasing the gene expression involved in fat oxidation in untrained men [5]. Wallis’ team saw suppressed fat oxidation in moderately trained men & women when glucose was ingested during exercise [6].

In contrast to the above trials on beginning and intermediate trainees, Coyle’s team repeatedly showed that carb ingestion during moderate-intensity (65-75% VO2 max) does not reduce fat oxidation during the first 120 min of exercise in trained men [7,8]. Interestingly, the intensity margin proximal to where fat oxidation is highest was unaffected by carb ingestion, and remained so for the first 2 hours of exercise.

Horowitz’ team examined the effect of a during-training solution of high-glycemic carbs on moderately trained men undergoing either low intensity exercise (25% VO2 max) or high-moderate intensity (68% VO2 max) [9]. Similar results to Coyle’s work were seen. Subjects completed a 2-hr cycling bout, and ingested the carb solution at 30, 60, and 90 minutes in. In the low-intensity treatment, fat oxidation was not reduced below fasted-state control group’s levels until 80-90 min of exercise. In the 68% group, no difference in fat oxidation was seen whether subjects were fasted or fed throughout the trial.

Further supporting the evidence in favor of fed cardio in trained men, Febbraio’s team investigated the effects of carb ingestion pre & during training in easily one of the best-designed trials on this topic [10]. Subjects exercised for 2 hrs at an intensity level of 63% VO2 max, which is now known as the point of maximal fat oxidation during exercise. Result? Pre & during-training carbs increased performance - and there was no difference in total fat oxidation between the fasted and fed subjects. Despite the elevated insulin levels in the carb-fueled groups, there was no difference in fat availability or fat utilization.

Summing Up the Research Findings

• At low intensities (25-50% VO2 max), carbs during exercise reduce fat oxidation compared to fasted trainees.
• At moderate intensities (63-68% VO2 max) carbs during exercise may reduce fat oxidation in untrained subjects, but do not reduce fat oxidation in trained subjects for at least the first 80-120 minutes of exercise.
• Carbohydrate during exercise spares liver glycogen, which is among the most critical factors for anticatabolism during hypocaloric & other conditions of metabolic stress. This protective hepatic effect is absent in fasted cardio.
• At the established intensity level of peak fat oxidation (~63% VO2 max), carbohydrate increases performance without any suppression of fat oxidation in trained subjects.





References

1.
Melanson EL, et al. Resistance and aerobic exercise have similar effects on 24-h nutrient oxidation.. Med Sci Sports Exerc. 2002 Nov;34(11):1793-800.
2. Ahlborg, G., and P. Felig. Influence of glucose ingestion on fuel-hormone response during prolonged exercise. J. Appl. Physiol. 1976;41:683-688.
3. De Glisezinski I, et al. Effect of carbohydrate ingestion on adipose tissue lipolysis during long-lasting exercise in trained men. J Appl Physiol. 1998 May;84(5):1627-32.
4. Coyle EF, et al. Fatty acid oxidation is directly regulated by carbohydrate metabolism during exercise. Am J Physiol. 1997 Aug;273(2 Pt 1):E268-75.
5. Civitarese AE, et al. Glucose ingestion during exercise blunts exercise-induced gene expression of skeletal muscle fat oxidative genes. Am J Physiol Endocrinol Metab. 2005 Dec;289(6):E1023-9.
6. Wallis GA, et al. Metabolic response to carbohydrate ingestion during exercise in males and females. Am J Physiol Endocrinol Metab. 2006 Apr;290(4):E708-15.
7. Coyle, et al. Muscle glycogen utilization during prolonged strenuous exercise when fed carbohydrate. J. Appl. Physiol. 1986;6:165-172.
8. Coyle, et al.. Carbohydrates during prolonged strenuous exercise can delay fatigue. J. Appl. Physiol. 59: 429-433, 1983.
9. Horowitz JF, et al. Substrate metabolism when subjects are fed carbohydrate during exercise. Am J Physiol. 1999 May;276(5 Pt 1):E828-35.
10. Febbraio MA, et al. Effects of carbohydrate ingestion before and during exercise on glucose kinetics and exercise performance. J Appl Physiol. 2000 Dec;89(6):2220-6.

[chrispghmuscle]

Well done Red.. Dam that's some nice reading material brother...

[moorey]

.

I got a fresh wax job and put on my speedo and wave to the hot neighbors around my hood..( LMAO < I threw that in for my boy Moorey) sup bro.LOL..[/quote]

yep thats my mate Chris! hahaha . When do I do cardio? when I have too, which means the weeks leading upto a show, Im doing 30 mins of HI after my workout!