What’s the proper way of doing cardio training, especially for a weightlifter not wanting to shed too much weight or lose muscle? The best time to jump on that elliptical trainer, treadmill, bike, step-mill, or hitting the pavement to do an outdoor jog is first thing in the morning on an empty stomach. This makes sense because you’re doing cardio without any insulin fluctuation or spike, your glycogen stores are empty from fasting over the last eight hours in the rack, and ultimately this means that your body will be drawing a high percentage of its energy from fat stores. All of this is bound to set the stage for optimum fat burning potential!

Now I don’t know about you, but I’m not one of those guys who enjoy getting up first thing in the morning to put myself through a grueling cardio session without a morsel of food in my gut. But for those of you who can, I give you all the credit in the world. I’m not saying that I couldn’t train first thing in the morning on an empty stomach, I’m just saying that I’d prefer not to.

For as long as I can remember, I’ve always felt better eating a decent sized meal about 45 minutes before training with weights (not cardio). This might not be in alignment with conventional thinking, but it feels right for me on a personal level. I feel like I can lift more weight, achieve a great pump and have enough energy to make it through my workout without losing steam. But let’s get back to the subject at hand – cardio. I’ve said my piece in regards to early morning training on an empty stomach, and in contrast I also wouldn’t be against cycling on and off a training program of morning cardio to maximize my fat burning potential.


The main reason for doing cardiovascular training first thing in the morning is simply to target fat with the potential to burn it. The theory behind this concept revolves around glycogen stores, depleting them and your body’s ability to switch to another source of usable energy – fat stores. We store glycogen in our muscle cells and liver. This is the gas tank for our body. Within our blood stream we have a certain amount of glucose (sugar) floating around for quick usable energy. That amount of blood glucose at any given time is no more than 4 grams (about a teaspoon). As it’s used up, it’s continuously fed from our glycogen stores from within the muscle and liver. The goal is to time your cardio training when the gas tank is close to empty, so it would make sense to do cardio first thing in the morning or immediately post-workout.

Keep in mind that the larger your muscles, the more capacity for glycogen storage, the fuller your muscles will look (glycogen is stored with water), thus the longer it takes for your body to deplete these stores. The average time it might take to blow through your glycogen is about two hours with moderate physical exercise. It would make sense then that this number could be shaved down substantially through higher intense physical activity such as interval training cardio. Fifty-yard wind sprints or cycling in a spinning class are perfect examples of ways to deplete glycogen stores in a hurry.

Blowing through your glycogen stores in two hours or less is a concept that you can happily throw out the window when you consider doing morning cardio on an empty stomach. Essentially you’re heading out of the starting gate with your body primed and ready to target fat cells. While insulin is the hormone responsible for storing usable energy (primarily released when consuming carbohydrates), the opposing hormone would be glucagon. Glucagon is released when insulin is low, like when you consume a high-protein low-carb meal. In fact, protein stimulates the release of glucagon. This hormone helps liberate fat as usable energy (the opposite of insulin, which helps store fat). Along with glucagon, epinephrine is another fat liberating hormone that is released through high intensity exercise or during a stressful situation. Unfortunately carbs also blunt the release of this hormone, thus taking us out of that fat burning zone.


So what’s the right amount of cardio in a given session? I often see people drudging along on those elliptical trainers for more than an hour at a clip. Usually they’re watching the television and sweating their asses off as the smell from last nights dinner permeates over to where I’m trying to do my cardio workout – yuck! Don’t be that person. As a weightlifter/bodybuilder, I believe it’s important not to do too much cardio training in one session. More than 30 minutes and you can start to compromise muscle, but less than 20 minutes and you’re not giving your body an opportunity to target fat stores.

Again, let’s talk about the morning cardio session. Say you’ve woken up, stumbled into the gym without any food whatsoever, and your body is primed to target fat stores because you’ve done nothing to cause an insulin response. In fact, higher levels of glucagon should be present, thus causing this shift toward fat burning as fuel. All of this sounds great, but for some people the concern may be a lack of energy. How are your sustained energy levels going to be to maintain the level of performance you’ll need to complete a solid 30 minute cardio session? The good news is that we adapt very quickly as human beings and after a few days on a cardio program you will train your body to rise to the occasion.

John Ivy, Ph.D. and Robert Portman, Ph.D. are the co-authors of books like Nutrient Timing, The Nutrient Timing System, and The Performance Zone. They state: “Do not cut back on nutritional supplementation. This will not help you lose fat. If anything, it will do the opposite. By fueling your exercise properly, you will be able to perform at higher levels for longer periods and burn more calories. By fueling your recovery properly, you will put calories to their best anabolic use.” So my take is that you should have some fuel in your system to maintain a certain level of intensity, thus setting up a more successful afterburn effect. Aerobic training, if done with proper intensity and duration can cause a rise in metabolism that will last for more than an hour to several hours after you finish training (called afterburn). Personally, I can feel this afterburn affect for as long as 3 hours post-cardio depending on how intense I go. I believe this can be achieved in a solid 20 to 30 minute interval training cardio session.


Muscle burns fat – that’s the good news! Doing marathon cardio workouts can cause a catabolic effect. In other words, cardio sessions longer than an hour can cause muscle wasting, which can ruin the possibility for optimum caloric burning potential through muscle development. Now don’t start to celebrate because you’ve got muscles and don’t have to do cardio anymore. And don’t camp out at your favorite all-you-can-eat restaurant either because your muscle mass allows you to burn more daily calories (50-75 calories per day for every pound of muscle). Essentially you’re creating a fat burning machine each and every time you hit the steel to make more muscles! But most importantly, balance between your diet, your cardio and your workouts is key. Just because muscle requires more calories to function throughout the day and during your training sessions, it doesn’t give you the green light to eat like a careless animal either. It’s still important to watch what you’re eating if you want to be lean.

I’ll be honest, there’s times when I’ll stay away from cardio all together just to add a little weight, but I don’t maintain this non-cardio training for longer than two weeks at a clip, and only lay off the cardio about two to three times a year. Keep in mind that I always train with high intensity levels and often fight to catch my breath during my workouts. This means that I’m still getting my heart rate elevated and working.


What’s the best alternative for targeting fat stores if you don’t want to train first thing in the morning on an empty stomach? It’s simple – make sure to eat a more protein based meal 2 hours before cardio training. If you want to eat any carbs, stick to those that are lower glycemically, containing more fiber and those which cause as little insulin response as possible. Raw or lightly steamed veggies drizzled with a little olive oil are a great choice along with a protein source like grilled chicken, poached fish or low sodium turkey. Also, hydrating after a meal with room temperature water is a must to help facilitate gastric emptying time and facilitate proper digestion. After those 2 hours go by you’re ready to hit it hard for optimum fat burning potential!

Another option is to train post-workout because you’re blowing through those glycogen stores just before hitting the cardio. I’ve tried this and see the benefits, but it leaves me with zero energy for cardio because of the intensity of my workout. This is when a good electrolyte drink might come in handy, sipping between post-workout and pre-cardio. Consume half, then continue to sip the remainder of the bottle throughout your cardio session.


I like to do 20 to 30 minutes of interval cardio training with my heart rate pumping at about 75 to 80% of its max for 2 to 3 minutes before pulling back and allowing it to come back down for another couple minutes. Most every modern piece of cardio equipment in the gym has an interval program available for you to choose, so this makes it easy. In a 20 to 30 minute cardio workout I’ll end up doing about 4 to 6 interval peaks and valleys. If you push yourself, you’ll reap the benefits within this relatively short span of time dedicated to heart health and body composition.

Live a High Integrity Life!
Gregg Avedon
Cahill GF (1971).  Physiology of Insulin in Man.  Diabetes, 20:785-799.
Andrich (2002).  No Mistakes, p.23.
Portman, Ivy (2004).  Nutrient Timing, p.18.
Armstrong, R., Biochemistry: Energy Liberation and Use.  Sports Medicine and Physiology. Ed. Strauss, R. Philadelphia, W.B. Saunders, 1979
Gollnick, P., “Metabolism of Substances: Energy Substrate Metabolism During Exercise and as Modified by Training,” Federation Proceedings, 44: 353-356, 1985.
Aceto, C. (1997).  Everything you Need to Know About Fat Loss, p. 123.
Portman, Ivy (2004).  The Performance Zone, p. 102.
Zinczenko, Spiker (2004).  The Abs Diet, by Rodale Press, p. 47..

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  1. Bryan Francis Says:

    Great info and very well explained. Thanks!


    GREAT POST GREG! TONS OF GREAT INFO! Everyone should read this, if they did, they would have more effective workouts, and better results.. You rock!

  3. sean Says:

    love morning cardio…gets my day off to a great start…and helps shred me up!

  4. shawn Says:

    Great piece of info!

  5. Anthony Says:

    Thoughts on a little caffeine pre cardio session in am? Help to jumpstart the metabolism and give a maximum boost? Just 50-100 mg? I’ve heard conflicting theories.

  6. Gregg Avedon Says:

    That’s okay depending on how your body responds to caffeine, your age, and how intense you’re pushing yourself when doing cardio. If you respond easily to caffeine and you feel jittery it’s probably not a good idea to do it prior to a cardio session. Depending on your age, calculate your max working heart rate (220 minus your age) and then make sure that you don’t push yourself above 85-90% of your max as it can put undue stress on your heart when combined with caffeine. Just be smart! The average cup of coffee contains between 80-135 mg’s of caffeine.

  7. Sean Says:

    Can I do cardio right after I hit the weight??

  8. Gregg Avedon Says:

    Absolutely. It may be a good idea to drink an electrolyte type drink or a recovery drink to give you the energy for your cardio. But this really depends on the intensity of your resistance workout prior to doing cardio and also the duration of your cardio session itself. For instance, if your workout was of moderate intensity and/or only lasted about 30 minutes, you can get away with htting a 20-30 minute cardio session with no recovery drink aside from plain H20 and still have decent energy levels to get you through your cardio session. If you resistance trained super intense for over 45 minutes, it may be a good idea to take a recovery drink prior to doing cardio to ensure that you maximize your intensity throughout the session.

  9. Tim Says:


    Cardio is a big thing nowadays to complement a weights program, throw in reformer pilates and that’s my routine each week. One thing I’ve noticed since ramping up my cardio and doing intervals is that I’m losing weight. I’m still working hard in the weights room, lifting for six reps so I can lift heavier. I’m eating well, in fact at times more than enough food, with a good balance coming from a lot of the recipes you have in Muscle Chow. My big thing, despite taking electrolyte replacements and recovery protein supplements (a thing that is big in Australia for us sporting types) after each cardio session, I’m still losing weight. I also take a good recovery protein after weights. Any idea on what I can do to gain the size I’m working so hard for? I’m not losing fat by the way, as I’m already about 10%, so anything else you can think of would be helpful.



  10. Gregg Avedon Says:

    Tim, If you’re ramping up your cardio that means you’re buring more calories overall and you are also creating an afterburn where you will continue to burn calories even after you leave the gym. If you’re eating the same amount of calories each day as you did prior to ramping up your cardio then it would make sense that you’re going to begin losing weight. One key factor for you would be to add in a high-calorie meal or shake each day. If you want to do a shake, check out “Muscle Juice” in my Muscle Chow book (page 199) as it has nearly 800 calories in one serving!
    And another factor, since you want to gain strength you’re keeping your reps in the 6 range, but if you want to create a little more hypertrophy and stimulate more muscle growth you should divide your sets and do several in the 8-12 range. This may also help create an adjustment for you that will benefit adding a little more muscle and holding onto more overall weight.
    Good luck, Gregg

  11. Tim Says:

    Thanks Gregg. And apologies too, mis-spelt your name when I asked you a question, so unintentional.

    I’ll give your idea a crack and see how I go. Having played AFL (better known as aerial ping pong to some guys I know in the USA), nutrition is a key focus for me. I have been on diets of about 6,000 calories a day, so I might start looking at that again. Oh the feeling of always being full.

    Thanks again, Tim

  12. Dustin Martin Says:

    cool post keep em going. keep chuggin brother! catch

  13. Tibor Jaczkó Says:

    Thanks Gregg for the clear info, now I know how to start the day tomorrow morning 🙂

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