What is Prime Exercise Time?

Continues from Exercise: Just Minutes in the Morning? by Tom Venuto

Whether or not morning cardio in the fasted state increases "real world" fat loss is still the subject of controversy, but there are many other reasons you might want to consider making it a part of your daily routine. G. Landry, despite his doubts about whether the fuel source matters, admits, "If I had to pick a single factor I thought was most important in a successful weight loss program, it would have to be to exercise first thing in the morning."

Here are some of the additional benefits of doing cardio early in the morning:

1. It makes you feel great all day by releasing mood-enhancing endorphins.

2. It "energizes" you and "wakes you up."

3. It may help regulate your appetite for the rest of the day.

4. Your body's circadian rhythm adjusts to your morning routine, making it easier to wake up at the same time every day.

5. You�ll be less likely to "blow off" your workout when it's out of the way early (like when you�re exhausted after work or when friends ask you to join them at the pub for happy hour).

6. You can always "make time" for exercise by setting your alarm earlier in the morning.

7. It increases your metabolic rate for hours after the session is over.

Of all these benefits, the post-exercise increase in your metabolic rate is one of the most talked about. Scientists call this "afterburn" effect the "excess post-exercise oxygen consumption" or EPOC for short.

Looking only at the number of calories and the type of calories burned during the session doesn't give you the full picture. You also need to look at the increased number of calories you continue to burn after the workout is over. That's right - work out in the morning and you burn calories all day long. Imagine burning extra fat as you sit at your desk at work! That's the good news. The bad news is, the degree of EPOC is not as great as most people think. It's a myth that your metabolism stays elevated for 24 hours after a regular aerobic workout. That only happens after extremely intense and/or prolonged exercise such as running a marathon.

After low intensity exercise, the magnitude of the EPOC is so small that its impact on fat loss is negligible. Somewhere between 9 and 30 extra calories are burned after exercise at an intensity of less than 60-65% of maximal heart rate. In other words, a casual stroll on the treadmill will do next to nothing to increase your metabolism.

However, EPOC does increase with the intensity (and duration) of the exercise. According to Wilmore and Costill in "Physiology of Sport and Exercise," the EPOC after moderate exercise (75-80%) will amount to approximately .25 kcal/min or 15 kcal/hour. This would provide an additional expenditure of 75 kcal that would not normally be calculated in the total energy expended for that activity. An extra 75 calories is definitely nothing Earth shattering. However, it does add up over time. In a year that would mean (in theory) you would burn an extra 5.2 lbs of fat from the additional calories expended after the workout.

One way to get a significant post exercise "afterburn" is high intensity interval training (HIIT). HIIT is done by alternating brief periods of high intensity work (85% or more) with brief periods of lower intensity work. Studies on the effects of HIIT have demonstrated a much higher EPOC, which can add substantially to the day's calorie expenditure. In one study, scientists from the University of Alabama compared the effects of two exercise protocols on 24-hour energy expenditure. The first group cycled for 60 minutes at a moderate intensity. The second group performed HIIT, cycling for two minutes at high intensity followed by two minutes at a low intensity. The group that performed the HIIT burned 160 more calories in 24 hours than the low intensity group. That means the HIIT group would burn an extra 11.8 pounds of fat in one year if they did HIIT five days a week instead of conventional training.

Ironically, weight training has a much higher magnitude of EPOC than aerobic training. Studies have shown increases in metabolic rate of as much as 4-7% over a 24-hour period from resistance training. Yes - that means bodybuilding does burn fat � albeit through an indirect mechanism. For someone with an expenditure of 2500 calories per day, that could add up to 100 - 175 extra calories burned after your weight training workout is over. The lesson is simple: Anyone interested in losing body fat who is not lifting weights should first take up a regimen of bodybuilding, then � and only then � start thinking about the morning cardio!

A common concern about doing cardio in the fasted state, especially if it's done with high intensity, is the possibility of losing muscle. After an overnight fast, glycogen, blood glucose and insulin are all low. As we�ve already concluded, this is an optimum environment for burning fat. Unfortunately, it may also be an optimum environment for burning muscle because carbohydrate fuel sources are low and levels of the catabolic stress hormone cortisol are high. It sounds like morning cardio might be a double-edged sword, but there are ways to avert muscle loss.

All aerobic exercise will have some effect on building muscle, but as long as you don't overdo it, you shouldn't worry about losing muscle. It's a fact that muscle proteins are broken down and used for energy during aerobic exercise. But you are constantly breaking down and re-building muscle tissue anyway. This process is called "protein turnover" and it's a daily fact of life. Your goal is to tip the scales slightly in favor of increasing the anabolic side and reducing the catabolic side just enough so you stay anabolic and you gain or at least maintain muscle.

How do you build up more muscle than you break down? First, avoid excessive cardio. Aceto suggests limiting your cardio on an empty stomach to 30 minutes, and then it would be "highly unlikely that amino acids will be burned as fuel." He also mentions that "a strong cup of coffee should facilitate a shifting to burn more fat and less glycogen. If you can spare glycogen, you�ll ultimately spare protein too." You might also want to consider experimenting with the thermogenic ephedrine-caffeine-aspirin stack (or it's herbal equivalent).

Second, give your body the proper nutritional support. Losing muscle probably has more to do with inadequate nutrition than with excessive aerobics. Provide yourself with the proper nutritional support for the rest of the day, including adequate meal frequency, protein, carbohydrates and total calories, and it's not as likely that there will be a net loss of muscle tissue over each 24-hour period.

Third, keep training with heavy weights, even during a fat loss phase. Using light weights and higher reps thinking that it will help you get more "cut" is a mistake: What put the muscle on in the first place is likely to help you keep it there.

Still petrified of losing your hard-earned muscle, but you�d like to take advantage of the fat-burning and metabolism-boosting effects of morning cardio? One strategy many bodybuilders use is to drink a protein shake or eat a protein only meal 30-60 minutes prior to the morning session. The protein without the carbs will minimize the insulin response and allow you to mobilize fat while providing amino acids to prevent muscle breakdown.

In conclusion, it seems that morning cardio has enough indisputable benefits to motivate most people to set their alarms early. But let's talk bottom line results here: Does it really result in more "real world fat loss" than aerobics performed at other times of the day or after eating? I have to believe it does. Experience, common sense and research all tell me so. Nevertheless, this will obviously continue to be an area of much debate, and clearly, more research is needed. In the meantime, while the scientists are busy in their labs measuring respiratory exchange ratios, caloric expenditures and rates of substrate utilization, I'm going to keep waking up at 6:00 AM every morning to get on my Stairmaster.

More about exercise timing:

Tom Venuto thoughts on workout timing


References

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