Question about low blood sugar

Triathlon Forum
1

Hello,

I was reading an article that is saying you should not eat/drink anything high on the glycemic index pre workout.

They are saying that if you do this you, will have an insulin responses and you will get low blood sugar during the workout. They are saying that your workout/race will suffer because of a drop in blood sugar.

What do you all think of this?

Thanks

Gall

2

That’s the general idea. Complex carbohydrates maintain a steady blood glucose level without the dramatic spike & crash effect that accompany simple sugars. Eating a peanut-butter whole-wheat bagel (or something with an equivalent GI) an hour before a race or workout will result in a sustained energy level superior to eating a donut or slice of pie.

Simple sugars (like gatorade) are fine for immediate and continued usage with shorter intervals between refueling, complex are better at sustaining over a longer period of time, allowing longer intervals between refueling (Gatorade every 15 minutes, complex-carb gels every 40-50 minutes).

3

More or less, yes, this might happen. The bit about low blood sugar depend on how long you exercise for. Insulin will do 2 important things:

  1. Increase carbohydrate and supress fat oxidation - therefore increased dependance on muscle glycogen for fuel, regardless of exercise intensity
  2. Shut off the liver - it won’t make any glucose at all, and is where/why the blood glucose problem might arise if you go for long enough. Loosely speaking, this will pretty much mean you are entirely dependent on what you eat for blood glucose supply from then on.

3 things to remember:

  1. Many “complex” carbohydrate foods are in fact high glycemic - don’t let that fool you. Smearing with high fat/protein spreads works, simply by slowing digestion, which is good, but still need to choose food wisely.
  2. To negate the effects of a spike in insulin (ie, an increase in reliance on CHO fuels, etc) you will likely need more than 1 hour, depending on what/how much you eat. A good dose of CHO, and subsequent insulin release can increase overall CHO oxidation for a good 2-3 hours.
  3. Timing of the meal before exercise is important, for example, if you eat immediately before you start, the increased sympathetic nervous system (ie adrenaline) activity will suppress the release and effect of insulin, minimising these changes.
4

If someone ate a gel 45 minutes before a race and then another 10 min before the start do you think they would get/feel an energy drop?

Maybe what I’m trying to say is do you feel that keeping the tank full before a race would spike the insuln (which also helps glycogen into muscles) and keep blood sugar high so your brain, which is a sugar hog, very alert.

jaretj

5

There are other variables to consider, such as the individual’s ability to maintain a normal blood glucose level (most are) and what was eaten prior to the gel (and when), but generally speaking, complex carbohydrates won’t cause the same insulin spike associated with ingestion of large quantities of simple sugars.

In your full tank example, if you kept filling the tank with simple sugars, you’ll most likely experience the spike and crash, whereas using a complex-carb gel prior to a race after eating a lower GI meal is less likely to do so. Also, the brain is the first organ to feel the effects of hypoglycemia, which is a pretty useful arrangement, all things considered. Your brain knows when you need fuel before your skeletal muscles deplete, kind of like the fuel light activating on your car’s dashboard. Simple sugars are the quickest way to recharge the brain (which doesn’t store glucose), and complex sugars are ideal for refilling the tank for the long haul. I tend to think of Gatorade as brain fuel & gels as body fuel.

My pre-race routine is universal, regardless of the sport or distance: complex meal 1-2 hours pre-race, followed by 20-30oz. 1/2 strength Gatorade, then a complex-carb gel 15 minutes prior to the start. During races lasting longer than 1hr, I go to the Gatorade every 15 minutes, then gels every 40-45 minutes (taken with water). I’ve used this system from oly to IM distance tris, 1/2 marathons to ultramarathons, and have never bonked or suffered gastric issues stemming from nutrition. Overestimating my abilities on race-day, on the other hand, has produced some spectacular blow-ups. I’m still trying to get the vomit out of my racing flats. :slight_smile:

6

Good explaination.

For big training days and racing I get my morning meal in, normally about 400 to 500 calories. Training just gets Gatorade and a gel about every 45 minutes while I typically eat the 2 gels before a race. The 2 gels seems to get me topped off and gives me somewhat of a caffien buzz. It has seemed to work well for me this year.

Now on longer runs during the week it seems as though my brain is telling me to slow down and I start feeling really tired. When I eat a gel I perk up in 3 to 5 minutes. I don’t think the fuel is getting to my muscles that quickly but probably is getting to my brain in that amount of time hence my “Brain needs a lot of sugar” idea. Does that make any sense?

jaretj