Hungry, shaky, sleepy, anxious, dizzy, confused, nervous, sweaty, irritable, or "hangry". Ever experience any of these symptoms right after starting a workout? These are symptoms of reactive hypoglycemia, or low blood sugar in response to exercise.  This is a condition that can occur under certain circumstances shortly after a person who is susceptible exercises. 

How It Happens

In response to eating carbohydrates our body releases insulin, a hormone that works to drive glucose (the main breakdown product of carbohydrates) into cells for storage or use. This process is what returns our blood sugar to normal following a meal - after we eat and digestion has begun, the sugars (glucose) in carbohydrates are released into the bloodstream and insulin's job is to bring those glucose levels down to a 'normal' level. 

Note: It's completely normal for blood sugar to rise following the ingestion of anything.  Of course, the more carbs/simple carbs one consumes, the quicker and higher their blood sugar will rise.  There are a lot of videos out there of people demonstrating how their blood sugar rises after eating all kinds of meals - it's supposed to do that!

Additionally, a separate process occurs independent of insulin in working muscles. You see, muscles can uptake and utilize glucose all by themselves, without insulin.  Mother Nature created this 'fail safe' system so that our muscles would never be deprived of energy to work. 

Now, imagine for a moment what could happen if both of these processes were to occur at their full capacity at the same time.  The combined action of insulin lowering blood glucose coupled with voracious muscles that are also pulling glucose from the bloodstream can drop blood sugar levels extremely quickly - this is what's known as reactive, or rebound hypoglycemia (also known as "bonking" in athletic circles).  In other words, your blood sugar plummets and is too low.  If you’ve ever had this happen, you know how tough it is to keep working out, much less even retain any composure!

Symptoms of Low Blood Sugar/Hypoglycemia/Bonking

• Extreme fatigue. Like, you want to lay down in the middle of the road kind of fatigue.
• No energy. Like, zero energy.
• You may feel hot and become sweaty.
• Anxious. "Hangry".
• Speaking of hangry, you'll have intense cravings for food - especially something sugary.
• Dry mouth, dizziness and extreme weakness.

Bonking is that feeling when you truly run out of gas. Most athletes have had this happen, regardless if you're a swimmer, runner, triathlete or any other type of athlete.

Fortunately, it's an easy condition to prevent. But that's the key, you've got to prevent it. Because once the dreaded bonk occurs, there goes your race!

Dietary Timing for Hypoglycemia

Historically, it was recommended to avoid carbohydrates before exercise altogether to prevent this phenomenon from happening; however, our viewpoint on this has changed.

In those that have experienced reactive hypoglycemia or are prone to it, the timing and type of carbohydrates before exercise is important. Since both blood glucose and insulin concentrations peak 20-40 minutes after eating a meal/snack, eating carbohydrates within the 10 minutes before starting to exercise or during the warm up is one strategy for treating reactive hypoglycemia. The sugar from the carbs is then released as the working muscles start requiring it, and this keeps insulin (mostly) out of the picture. This is thought to result in a much less precipitous, reactive drop in blood sugar.

Also, choosing low glycemic index (GI) carbohydrates, such as a slightly under-ripe banana, may also help. The glycemic index refers to how quickly a food can raise blood sugars.  A low glycemic carbohydrate will cause sugars to rise more slowly than high glycemic carbohydrates, resulting in a gradual (versus rapid) rise in blood glucose and therefore insulin levels will also be lower. 

If neither of these strategies work for someone who is prone to reactive hypoglycemia, avoiding all carbohydrates within 90 minutes of exercising might be worth a try. At this point, blood sugars should be stable and no longer affected by any changes in insulin levels. 

Note: You may be thinking "oh my gosh, no food before a workout?"  Yes, that's right.  In truth, we all have multiple hours of stored carbohydrate in our liver and muscles, known as glycogen.  Unfortunately we've all been sold by the makers of sports drinks, bars and gels that we need energy right then and there or we'll crash. Not true - give it a try (no food before a workout lasting under 75 minutes) and you'll do just fine.  

Hypoglycemia Dietary Basics

Outside of exercise, paying close attention to the timing and composition of meals and snacks can help manage reactive hypoglycemia.

• Eating small meals and snacks no more than 3-4 hours apart throughout the day can help keep blood sugar stable.
  
  
• High-fiber foods (whole grains, fruit, and vegetables), lean proteins (animal and non-animal sources), and healthy fats (nuts, seeds, avocado, fish, and liquid oils) as part of a well-rounded diet can help.  In fact, most people don't get enough protein on a daily basis as is.  Increasing your protein intake will drastically improve your tendency toward hypoglycemia. 
  
  
• Limit or avoid simple high GI carbohydrate foods (soda, sports drinks, breads, pastas, candy, etc.), particularly on an empty stomach. And if you choose to consume alcohol, avoid sugary mixers and be sure to have some food on board when you do drink.

Nutrient Solutions

Despite these dietary solutions, some individuals still struggle with reactive hypoglycemia.  These are the cases where we need to look at and evaluate the use of specific nutrients which can help improve how the body deals with carbohydrates. 

The botanical medicines Momordica charantia  and Gymnema sylvestre slow how glucose is absorbed from the gut and support the pancreas (where insulin is made).

Chromium, vanadium, zinc, copper and magnesium are all minerals that play a vital role in how our cells interact with insulin.  By supplying these nutrients, the pancreas releases insulin in a more measured way and the cell's ability to absorb and utilize sugars is improved as well. 

Supplementing with all of these nutrients has helped a lot of our client-athletes minimize their reactive hypoglycemic symptoms along with getting more detailed with their diets as far as understanding each person's unique tolerance or intolerance to simple carbohydrates. 

We really like Glycemic formula because it contains all of these nutrients in a synergistic combination - it contains the 9 most effective natural ingredients known for their ability to optimize blood sugar levels so they stay balanced. You can read more about how it works here.

Everyone is different in how their body tolerates carbohydrates. If you do suffer from reactive hypoglycemia, experiment with the type and timing of meals prior to working out. 

This is a treatable symptom of dietary imbalance that can be improved and corrected with strict attention to meal timing with exercise, type of carbohydrates that are tolerated by the individual, protein and fat to carb ratio, and supporting it all with the blood sugar balancing nutrients found in Glycemic Formula. 

Here's a more detailed video about preventing reactive hypoglycemia:

References

1. Glycemic Index. (2020, August 10). Retrieved from http://www.glycemicindex.com/.
   
   
2. Jeukendrup, A. E., & Killer, S. C. (2011). The myths surrounding pre-exercise carbohydrate feeding. Annals of Nutrition and Metabolism, 57(Suppl. 2), 18-25.