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Don’t waste a workout! How to maximize the mythical “30-minute Window”

April 12, 2012

Post-Workout Nutrition: The 30-Minute Window

Jeff Knight, M.A., M.Ed.

Assistant Coach, TeamROGUE Elite



When is the 30-Minute Window important:  Long runs or quality workouts (i.e., hill repeats, intervals, tempo runs, etc.)

What to eat: Because of the convenience, chocolate milk or some other carbohydrate-/protein-based recovery drink (i.e., Pure Sport or Fluid) in the first 30 minutes is best. Otherwise, any high-carb food will work. Follow this up with healthy, carb-based foods periodically over the next 6 hours.

How much: The average 150 lb. person, should consume 105 g of carbs within the first 30-45 minutes (0.7g/lb.) or ~30 oz. chocolate milk.


Most of us know that it’s important to refuel as quickly as possible after a long run or hard workout but what’s really the rush? And….what’s the deal with chocolate milk?

Our Bodies are a Wreck After a Run

To answer this question, we need to first think about a couple points.  The first is, runners need to replenish energy stores.  Secondly, runners need to switch their bodies to a “constructive state”.  To expand the first point, when we run hard (i.e., tempo/lactate-threshold runs, hill repeats or intervals) our body uses glycogen as the primary fuel source.  Glycogen is simply long sugar chains stored in our muscles. It burns quick and provides energy fast.  Also, glycogen is a crucial post-run energy source.  It acts in building new muscle and gaining the benefit of a hard workout; that is, it allows our bodies to make the changes they need to make to get faster and allow us to set new PRs. The problem is we don’t have a lot of it and a hard workout can completely empty our glycogen stores.    Now onto the second point, when we run our bodies go into a destructive (catabolic) state our bodies are doing everything they can to make fuel available for the run. Meaning, muscle, fat and glycogen are all being broken down to provide energy for the task at hand.  Essentially, we go into “survival mode”.  When we stop running, we obviously want to stop these processes and shift into a constructive (anabolic) state, where we build muscle, blood vessels, lactate-buffering mitochondria, stronger hearts, etc. The key to switching modes is insulin.

Classically, insulin is a hormone that’s released when we eat.  It controls the floodgates into our cells.  When we have a lot of sugar floating around, like after we eat, it is released and opens the floodgates.  After a run, insulin levels are low. If we can get insulin levels high after a run, sugar will flow freely into the cell, providing the raw material needed for replenishing our glycogen stores. Also, insulin stimulates muscle growth and blunts muscle breakdown while increasing muscular blood flow.   The beautiful thing is, after a run our bodies are extremely receptive to insulin.

So the goal is to rapidly get insulin levels high while, ensuring our body will be receptive to the insulin. This brings us back to the original question:  why do we need to refuel in the first 30 minutes?

The 30-Minute Window

As mentioned before, our bodies are extremely sensitive to insulin after a run.  During this time our bodies are willing and able to refill glycogen stores, make stronger legs and hearts and do the things necessary to make us faster.  After a hard run, insulin will open even more floodgates than they normally do after a meal. Unfortunately, we don’t stay extremely receptive to insulin.  Our bodies are at their insulin-sensitivity peak 15 to 30 minutes post-run, hence the 30-minute window. During this window, our bodies will replenish glycogen stores at a 50% faster rate! We stay fairly sensitive out to about 45 minutes.  After 45 minutes, insulin sensitivity starts to drop off to the point that if you wait 2 hours to eat after a hard workout or long run; your body is actually insulin insensitive.  That is, you are like a type-1 diabetic in the sense that even less floodgates will open than normal.   Moreover, if we refuel within the first 30 minutes and continue to refuel every 30-45 minutes after a run, we will stay ultra-insulin sensitive for up to 6 hours! So, if you continue to sip on chocolate milk or snack on pretzels you will maximize the benefits of a hard workout and the rate of recovery.

You need to eat quickly and often after a long run or hard workout.  So grab a chocolate-milk or sports drink and drink it while you stretch, ice and socialize.  Your body will feel better and your times can get faster.

When is the 30-Minute Window Important?

Is the window important after every workout?  Well, the more important question is: How hard did you run?  When you run at an easy, conversational pace you use mostly fat as a fuel source.  Since the majorities of your runs during the week will be at an easy pace for about an hour or less, glycogen stores won’t really be depleted.  Furthermore, since these runs aren’t really intense, our bodies don’t really go into “survival mode”.

“Well what about the long run, I run that at a conversational pace?”  The key here is you burn mostly fat at this pace; but the rest of the fuel comes from glycogen.  What I mean is, the long run is the “crock pot” of glycogen usage – the steady, subtle burn of glycogen over 1 ½ to 3 hours ultimately results in a depletion your glycogen stores.

The point is, runners really only need to stress about the window after long runs and hard-workout (quality) day, where the glycogen stores are depleted. Which for most of us means two to three days a week.  On the other days, where the runs are short and easy, the window is less vital but a small snack after the run wouldn’t hurt.

Now, if you are trying to lose weight while training, post-workout is not the time to skimp.  Caloric sacrifices should be made at other opportunities.  Replenishing those glycogen stores and turning your body to a constructive (anabolic) state will ensure that you receive the maximum benefits of your workout and prime you for your run the next day.

What to Eat and How Much: The Recovery Formula?

When it is time to eat, you want to target food or drinks that are: one, high in carbohydrates and two, have some protein. Adding protein helps your body recover even better but that’s a whole different topic!  The ideal carbohydrate to protein ratio is roughly 3:1.  So if you’ve ever wondered why chocolate milk is recommended, a serving of chocolate milk has about 28 g of carbohydrates and 9 g of protein.  That’s a ratio of 3.11:1.  Not bad.  Again, as far as recovering from endurance-based activities, the main focus should be carbohydrates, not protein.  Thus, I would recommend a sugary sports drink over a protein shake.

If you’re wondering how much to consume within the first 30 minutes of exercise, you want to eat or drink enough so that you get 0.7 g of carbohydrate and 0.2 g of protein for every pound you weigh (or 1.5g/kg of carbs and 0.5g/kg of protein).  For example, if you weigh 150 lbs., you need to consume 105 g of carbohydrate and 30 g of protein.  That’s equal to about 30 oz. of chocolate milk!  This may sound like a lot of calories, (210 calories per 8 oz. serving equals about 800 calories) but after 8 miles of running you burn about 800 calories.  Thus, 30 oz. of milk or carbohydrate-based recovery shake is more than covered on a long run or hard workout. After the 30-minute window, though, your body will still need carbohydrates.  In fact, it’s important to continue getting carbs and proteins over the next 6 hours!  The goal is to consume another 1.5-2g of carbohydrates for every pound you weigh (3.5 to 4 g/kg).  If you weigh 150 lbs., you should consume another 225 g to 300 g of carbohydrates within that following 6-hour window.  Now, you might be thinking, “That’s a lot of milk! No way am I drinking milk all day!” I agree. Thus, I recommend a carb-packed breakfast and lunch.  The carbs and proteins your body needs don’t have to be consumed in a liquid form; just eat a good breakfast and lunch.  I didn’t include protein in the above formula because if you eat “real” food (i.e., granola and yogurt, breakfast tacos, etc.) you will most likely consume some protein.  But if you are curious, the formula is: 0.5-0.7g/lbs. or about 1-1.3g/kg of protein 30 minutes to 6 hours post-workout.

Luckily, this part of the recovery formula isn’t really a problem (considering Juan in a Million is just down the road!).  The problem comes from skipping the carbs right after the run, considering the important role this plays in recovery, so it would be prudent to weave the “30-minute nutrition” into the foot drills, ice baths and stretching for faster recovery and more effective workouts.


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