Personal Training Experience

If you don’t replenish your muscle glycogen, exercise is harder. You can replenish muscle glycogen from non-carb sources through gluconeogenesis, but it takes longer.

For shorter and less intense workouts, you can adequately replenish with less carbs. And you don’t need a lot of muscle glycogen to do lower intensity efforts. You can walk all day without carbs.

But for harder and longer efforts, or for repeated efforts at higher intensity, it is much harder to continually replenish your muscle glycogen without sufficient carbs.

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Ah, so you may need longer duration downtime between exercise intervals.

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Yes. But it depends on the intensity and duration of the exercise.

Hard but short efforts may not use a whole lot of muscle glycogen. So you could probably do those daily. For example, a 100 meter dash would be almost entirely muscle glycogen from your legs, but a very small amount. So doing that daily would be easy.

Longer efforts that are easy, like a very long walk, would predominately use fats, so those could be done daily.

But if you start to burn up a lot of your glycogen (longer and/or harder efforts), that is when it starts to drain the tank.

Some people use their heart rate to calculate how much fat they are burning. Those are just estimates, and vary based on a person’s fitness. But in general, the higher your HR, the more carbs you are burning and the less fat.

It can be calculated exactly how much fat versus carbs you are burning by using your RER.

RER (Respiratory Exchange Ratio) is the ratio of how much carbon dioxide you are making divided by how much oxygen you are consuming. This gives an exact number, because there are formulas that show how many molecules of oxygen are used to create ATP from a single molecule of carbohydrates, and how much ATP it creates. And we also know how many molecules of oxygen are used to create ATP from a single molecule of fat, and how much ATP it creates.

When your RER is 0.85, your are using 50% carbs and 50% fat for fuel. Lower numbers mean you are using less oxygen, and higher numbers mean you are using more oxygen.

You can’t calculate RER yourself, you need to be in a lab. They use devices that measure breath volume, and oxygen and carbon dioxide analyzers.

But sorry, that’s just a tangent.

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Very cool. Thanks! I haven’t thought of Adenosine Triphosphate in 100 years. :slight_smile:

S

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@Chris That’s an interesting article, but requires a lot of steps and preparation. I’m one that likes to eat on the “spur of the moment.” I’ve had my share of enjoying the preparation of a meal, but that’s pretty much in the past. I’ve have had a devil of a time pre-blousing for meals; I know, it’s key, I just don’t do it well…perhaps my way of revolting. I’m thinking the methods indicated may be good for sushi (an old favorite that I’ve cut way back on).