Scientific Reports........

[XxDAHULKxX]

Hey guys, i'm taking a clinical nutrition class in college and some guy did a presentation on how fat is lost faster while doing cardio in the morning on an empty stomach than in the evening. The teacher was disagreeing because supposedly he said that he couldn't find any scientific studies that backed up the student's view. Maybe you all can help me out. Are there any links out there that claim this theory/fact with references? He'll give 5points on overall average grade if someone takes him a report. Thanx!!

[workinhard]

from = http://www.sixpacknow.com/fatlosstips.html


Maximum fat loss - the Best time for Cardio?
Many people don't realize just how important a well timed cardiovascular program is when comes to eliminating body fat. Whether it's early morning, late evening, the most important thing is that you just do it. Continuous cardiovascular exercise, such as running, walking, jogging, stair-climbing, or cycling, sustained for at least 30 minutes, will burn body fat no matter when you do it. However for the maximum benefits of fat loss you MUST ensure that your performing your cardiovascular training first thing in the morning. You should consider getting up early and doing cardio before you eat your first meal - even if you're not a "morning person." Early morning aerobic exercise on an empty stomach has three major advantages over exercising later in the day.

Early in the morning before you eat, your levels of muscle and liver glycogen (stored carbohydrate) are low. If you eat dinner at 7 p.m. and you eat breakfast at 7 a.m., that's 12 hours without food. During this 12-hour overnight fast, your levels of glycogen slowly decline to provide glucose for various bodily functions that go on even while you sleep. As a result, you wake up in the morning with depleted glycogen and lower blood sugar - the optimum environment for burning fat instead of carbohydrate. How much more fat you'll burn is uncertain, but some studies have suggested that up to 300% more fat is burned when cardio is done in a fasted, glycogen-depleted state.

So how exactly does this work? It's quite simple, really. Carbohydrate (glycogen) is your body's primary and preferred energy source. When your primary fuel source is in short supply, this forces your body to tap into its secondary or reserve energy source; body fat. If you do cardio immediately after eating a meal, you'll still burn fat, but you'll burn less of it because you'll be burning off the carbohydrates you ate first. You always burn a combination of fat and carbohydrate for fuel, but depending on when you exercise, you can burn a greater proportion of fat relative to carbohydrate. If doing cardio first thing in the morning is not an option for you, then the second best time to do it would be immediately after weight training. Lifting weights is anaerobic (carbohydrate-burning) by nature, and therefore depletes muscle glycogen. That's why a post lifting cardio session has a similar effect as morning cardio on an empty stomach. The second benefit you'll get from early morning cardio sessions is what I call the "after burn" effect. When you do a cardio session in the morning, you not only burn fat during the session, but you also continue to burn fat at an accelerated rate after the workout. Why? Because an intense session of cardiovascular exercise can keep your metabolism elevated for hours after the session is over. If you do cardio at night, you will still burn fat during the session, so you definitely benefit from it. However, night time cardio fails to take advantage of the "after burn" effect because your metabolism drops like a ton of bricks as soon as you go to sleep. While you sleep, your metabolic rate is slower than any other time of the day.

Burning more fat isn't the only reason you should do your cardio early. The third benefit of morning workouts is the "rush" and feeling of accomplishment that stays with you all day long after an invigorating workout. Exercise can become a pleasant and enjoyable experience, but the more difficult or challenging it is for you, the more important it is to get it out of the way early. When you put off any task you consider unpleasant, it hangs over you all day long, leaving you with a feeling of guilt, stress and incompleteness (not to mention that you are more likely to "blow off" an evening workout if you are tired from a long day at work or if your pals try to persuade you to join them at the pub for happy hour.)

You might find it hard to wake up early in the morning and get motivated to workout. But think back for a moment to a time in your life when you tackled a difficult task and you finished it. Didn't you feel great afterwards? Completing any task, especially a physically challenging one, gives you a "buzz." When the task is exercise, the buzz is physiological and psychological. Physiologically, exercise releases endorphins in your body. Endorphins are opiate-like hormones hundreds of times more powerful than the strongest morphine. Endorphins create a natural "high" that makes you feel positively euphoric! Endorphins reduce stress, improve your mood, increase circulation and relieve pain. The "high" is partly psychological too.

[workinhard]

from = http://www.muscle101.com/old_page/cardio.html

Surely you've noticed that you breathe heavier, and your heart beats faster when you excercise, do you have any idea why? To get more oxygen to the muscle. Oxygen is used in fat oxidization, a.k.a. fat burning. In fact, measuring the rate of oxygen consumption is one method used in determining amount of fat burned up (glycogen oxidization also occurs though).

So the cardinal rule of cardio is to reach and maintain a certain target heart rate. This target heart rate gets lower as you get older, maybe because the target heart rate is a % of basal metabolic rate which drops as you age as well(except maybe in very active folks). This is a speculation of mine, so I'm not 100% sure why this is.

Regardless, your heart has to beat faster! So why not beat as fast as possible, why only a range from say 120-150 beats per minute(bpm)? Too high an intensity causes glycogen stores to be mobilized, causing lactic acid buildup, muscle fatigue, and muscle cramps. Also leads to greater utilization of intra-muscular fat stores (not really bodyfat), and muscle protein for energy which means muscle breakdown.

When comparing 25% VO2 max. with 65% VO2 max. (light intensity(could do it for 10 hours) vs. medium intensity (could do it for 1-4 hours)), there are som interesting results. 25% intensity uses more % calories from body fat than 65% intensity, but total calories burn are say 70 vs. 110. So though the percentage is less for 65%, the net calories from body fat will be higher.

So medium intensity may be quite beneficial as well. So where to the rest of the calories come from during medium intensity exercise? Well, intra-muscular fat stores play an important role at this level. This fat isn't really considered body fat, as it is stored in the muscle cells themselves. So if we burn more of these during medium intensity exercise, would it not be safe to say that these stores must be replenished as well?

I would venture to say that medium intensity may be the way to go because it burns more net bodyfat calories than light, and excess fatty acids in the blood after exercise may get stored in the muscle to replace used up intra-musclular fat instead of body fat again.

Maybe this is one of the reasone interval training has become quite popular lately. This is probably the best overall way to do cardio. It mobilizes body fat and intra-muscular fat, and can be sustained for longer than medium intensity alone could (an is probably more comfortable as well).

I would also like to say that no cardio session should exceed about 40 minutes. Anything past this tends to promotes muscle protein breakdown in a big way. If you really want to do more cardio, split it up into several smaller sessions per day.
When to do Cardio
Lately, I have been reading a lot of articles claiming the early morning, before breakfast to be the best time for cardio. The main arguement being that working out on an empty stomach causes greater fat mobilization for energy, because glucose levels are low.

Since Muscle Media, a very reputable magazine that backs most of their information with research, also claims this, I hesitate to dispute this theory. But, being an academic, I can't help but wonder.

Low intensity exercise, and in fact, basal metabolism burn primarily fat for energy. Glucose is spared for use by nervous system since it can't use fat at all. So regardless of glucose availability, fat will be burned first if it can supply energy fast enough (hence low intensity is necessary).

However, eating a meal causes inulin release which definitely interferes with fat mobilization, so doing cardio, or even working out shortly (less than 1 hour) after a meal will be inefficient at best. So the real question is how long it takes for insulin to be cleared out of the system, which also depends on the meal. Chances are, insulin levels wouldn't drop to pre-breakfast levels for about 4 hours. And not eating for 4 hours can be quite unpleasant.

I can't really dispute this accepted fact of cardio timing, but what bothers me is that upon waking up, nitrogen level is very low, and cortisol (stress hormone) is way up. An ideal environment for muscle catabolism, and yes, fat catabolism as well(this presence of cortisol is probably what makes early morning cardio so effective). But I don't want my muscle wasting away in the morning.

A compromise: What I like to do now to get the best of both worlds, is upon waking up, have a small protein shake (no carbs for minimal insulin response) or supplemental glutamine (primary amino acid muscle is broken down for) or HMB (also involved in preventing muscle catabolism), and do my cardio about a half hour later. I may also supplement with caffeine/aspirin/ephedrine to maximize fat mobilization/burning.

But what about doing cardio after eating? Like I said, fat is mobilized in favour of glycogen even if the latter is readily available, so as long as you wait until insulin has been cleared out of your system (1-4 hours, depending on meal), cardio should burn as much fat as in the morning.


This was my previous argument:
One last thing, cardio in the morning will definitely burn more fat because metabolism and stress hormones are already elevated. Say, without cardio you burn 10 grams of fat per hour, with cardio you burn 50 grams per hour, total of 60 grams. If you do your cardio in the afternoon, you may only burn 5 grams per hour without, but you'd still burn 50 during cardio, total of 55 grams. Sure it's less, but you burnt the 10 grams/hour in the morning already.

Was that confusing? Let me summarize: you burn more basal metabolic calories in the morning than in the afternoon, so when you add cardio, it'll look like the total calories are higher, but for the entire day, it would be no different!

This arguement of mine is just to give peace of mind to people who can't, or don't want to do cardio in the morning. I prefer cardio in the morning cause it wakes me up, gets it out of the way, and its easier to stick with (harder to find excuses to skip it)!


This is my new argument:
It may be that cortisol only causes more fatty acid mobilization, but not necessarily oxidization. So doing cardio in the morning is better because you actually burn all the fatty acids that have already been mobilized by stress hormones.
So when to do it?
Cardio sessions should be 20-40 minutes, 3-4 times a week.
Do cardio first thing in the morning.
Take caffeine/ephedrine/aspirine and 20-30 minutes before cardio.
Wait 30-60 minutes after cardio to burn up remaining fatty acids in blood.
Drink lots of water before, during, and after cardio for waste removal.
Use interval training, i.e. vary the intensity.

What Cardio to do and how long
Any exercise you do that gets your heart rate up to your target range will suffice. You may find exercises that use more muscle will do this easier, and may in fact burn more fat. The most important aspect of your cardio activity of choice: you should enjoy it!

Easier said than done!! If you can play some sports with friends, or go for a scenic rollerblade with a friend, it's far better than sitting on an excercycle! If you are stuck on an excercycle, stair climber or whatever indoor equipment, reading a magazine usually really helps pass the time more quickly.

I remember always hearing 'you have to do cardio for at least 20 minutes before you even begin to burn fat'. Again, I beg to differ. You burn fat before you even begin your cardio session! But if you ate a lot of fat recently, you may have high lipid concentrations in your blood which could delay body fat mobilization.

If you can do multiple shorter sessions per day, it may be as good, if not better than one 30-40 minute session. This is because your metabolism stays elevated for a short period even after you finish your cardio. So elevating your metabolism 3 times a day may result in more overall fat utilization than one 40 minute session.

But that's not very practical, so most of us have to live with one session (fine by me!). The accepted amount is 30-40 minute 3-5 times a week, depending on your goals, and your schedule. I'll list a few different exercises, and how many calories each one burns per hour to help you choose an exercise and session duration

[workinhard]

http://www.ifafitness.com/faqs.htm

[workinhard]

http://www.straightblastgym.com/diet2.html

[workinhard]

from = http://www.intense-workout.com/cardio.html


Cardio: The best time of the day to do cardio for maximum fat loss, and why.
WARNING: What you are about to read is the answer to the most common question people have about their cardio/aerobic workout. What you are about to read is all 100% true! What you are about to read is the answer to the question that personal trainers and fitness magazines will make you pay for. Enjoy..

This is another time where what I am writing is inspired by questions people have mailed to me. So, be sure to keep those questions coming so I have more material to write about. =]

Now, on to the question. When is the best time of day to do cardio, and why? Well, I bet most people do cardio "whenever they get a chance." Sometimes during the middle of the day, sometimes before bed, sometimes directly after your weightlifting workout, sometimes directly before the weightlifting workout and sometimes first thing in the morning. The truth is, all of those times will get results. It doesn't matter what time of day you do your cardio workout, you will be burning calories every time. BUT, the real question is, which of those times is the most effective? And the answer is (drum roll please).... first thing in the morning!

Doing cardio first thing in the morning, on an empty stomach, before you eat anything, is by far, the most effective. Whether you run, jog, walk, swim, jump rope, take an aerobics class, ride a bike, etc., doing it first thing in the morning is the best time to do it for maximum fat loss. Why? Its simple. When you do your cardio workout, you are burning calories. Lets say you wake up, eat breakfast, eat lunch later in the day, and then a few hours after lunch, you do your cardio. All you will be doing during that cardio is burning the calories and carbs of the food you just ate. When you do cardio first thing in the morning, you haven't eaten anything for the last 8 or so hours because you were sleeping. So, when your body sees that there are no carbs to burn, it goes directly to stored bodyfat. And stored bodyfat is the fat that is on your body, which is the fat that you want to lose!

Understand how it works? When you do your cardio sometime during the day other then first thing in the morning, you spend most of that time burning off carbs that you already ate that day. When you do it first thing in the morning, there are no carbs to burn, so all your body can burn is body fat!

Some people have e-mailed me asking what type of cardio I do and I tell them I jog on my treadmill first thing in the morning. Even though I do all of my weightlifting at a gym, I do my cardio in my house on my own treadmill so I can do it first thing in the morning without having to take a shower, get dressed and do whatever else I'd do if I went to the gym to do cardio.

[workinhard]

http://www.gofigure.co.nz/ggfp-timing.html

[workinhard]

http://www.bodybuildingpro.com/cardiotiming.html

[workinhard]

http://www.convictionsoftheheart.com/home/health/Cardio-Fitness.htm

[workinhard]

http://www.womenfitness.net/cardiotiming.htm

[workinhard]

Now GO get that teacher!

[trip]

Man, what kind of a teacher is this person.

This theory has been around for 20 years, studies have been done, did he not want too look himself.

Seems like for this guy if it ain't in the book he's using it doesn't exist.

Betcha he still believes in Govt. Food Pyramid and that Atkins/CKD doesn't work.

[XxDAHULKxX]

Thanx alot guys! I had some of those already, but he is specifically looking for studies, sources of i guess medical journals or something. Dumb ass teach!

[musclebuilder]

JMO, but I like to do cardio with some carbs in me. I feel like I train harder and longer. I feel better anyhow.

[AnotherUser]

you should check out the Atkins site. I'm sure there are some links to a few studies. I would find 2 studies... one that shows that cardio with low blood sugar results in greater fat oxidation.... and another that shows that blood sugar is lower in the morning.... put the two together, and.......