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Sympathetic Nervous System Overload: Why Stress Matters For T1D Management And Exercise

A Fast and Long Day

On day 10 of my #T1Determined Type 1 Diabetes Run Across Texas, I had a little over 300 miles behind me. I had just finished a 41-mile day running on TX-302, a busy oilfield road that connects the tiny town of Kermit, TX with Odessa.

I had run a fast pace that day, partly because we didn’t have a lot of free time between sunrise and sunset and I didn’t enjoy running in the dark on a 2-lane road that had semi trucks whizzing by at 70 mph.

As a result, I had either taken my meals walking or simply cut them short, slamming down whatever I could stomach and hoping it had enough calories to take me to the next stop.

A Blood Glucose Minefield

Stress is its own little special kind of hell for Type 1 diabetics. I wrote a fair bit about the Type 1-specific challenges of fueling, overnight lows, and the like here.

To make things more difficult, my blood glucose had been running high nearly all day. Not a single reading was below 200 mg/dl, and I was barely taking on any carbs.

In situations like this one, when we’re not taking on new fuel, our bodies are pretty smart at using onboard energy stores to power through. I wasn’t eating enough and I was running fast, so I was burning through a fair bit of my glycogen stores as well as body fat and protein. The small amount of dietary fat and protein I was taking on wasn’t nearly enough to cover a daily drain of 5500-6000 calories.

As I’ve written about here, the balance between fueling, insulin sensitivity and stress is a complex one. Physical stress can cause your body to dump glycogen (to help you escape the metaphorical “cheetah” it thinks you’re fleeing), and when you don’t have time (or take time) to eat, it also switches to backup energy sources. The net effect of stress on people with type 1 is to hold blood sugars high while the stress remains. But as you slow down, eat, and relax, your body switches to a mode where it converts the new energy from food into glycogen, replenishes your glycogen stores, and makes your body more effective at using the insulin you have on board to store energy.

This means that while your blood sugar may be high during a long, stressful run, when you stop, it can “tank” precipitously.

That’s exactly what happened to me that evening in Odessa. After getting a shower, getting dressed, and heading off to dinner, my blood sugar started a long, hard dive.

By midnight, it was 30 mg/dl, I was wavering in and out of consciousness, Leslie had given me an emergency glucagon treatment, and I had drunk nearly all the orange juice we had in the van’s fridge.

What Could I Have Done Differently?

Looking back, I realize several things:

  • I should have eaten more during the day instead of forcing my body to tap glycogen and fat stores for energy
  • I should have eaten something even when my sugar was high, and dosed appropriately, so that I was taking on new energy
  • I should have moderated my pace and focused on keeping breaks short instead of running fast
  • I should have done something to reduce the stress

I knew in my heart that I had not taken the appropriate fueling strategy. That one’s on me.

Granted, it’s easier said than done to reduce stress when despite all your planning, you find yourself on a highway you don’t even feel comfortable driving on. But it’s something you have to try.

What is Sympathetic Nervous System Overload?

While it may be somewhat of an oversimplification, broadly speaking, the Sympathetic Nervous System is made up of the systems in your body that manage alertness to stressful situations.

Introduce a little danger, and your sympathetic nervous system goes into overdrive: your heart rate goes up, your respiration increases, you feel a surge of adrenalin, and your body goes into fight-or-flight mode, increasing blood glucose and making more energy available to the muscles, relying on its own energy store, and helping you “escape the cheetah.”

The more stressful inputs your sympathetic nervous system encounters, the more aggravated things become. If you’re not able to avoid, redirect, or reason your way out of the stress, outright panic can set in. If the situation is bad enough for long enough, “traumatic stress” can take hold.

A Navy doc friend of mine introduced me to the idea of sympathetic nervous system overload. I like to think of it as “pre-PTSD.” It’s not something you can just “Zen” your way out of by thinking positive thoughts–you have to actively manage it.

The Parasympathetic Nervous System

Your parasympathetic nervous is the “yin” to the sympathetic’s “yang.” It’s what kicks in when the crisis has past, you’re a little shaken, and you feel like you could eat a horse and sleep for 12 hours. Strangely, it’s a time that’s just as energy-consumptive as exercise, but in a different way. Blood sugars can run low as onboard energy is directed to replenishing depleted stores.

During that time, your body refills the glycogen “gas tank”, takes out the cellular “garbage”, and rebuilds damaged muscle.

The parasympathetic nervous system also plays a role in calming you down. You can’t take “air traffic control” conditions for very long before you start making critical mistakes.

Under sympathetic nervous system overload, it’s critical to not “lose it” amidst the stress. But that’s easier said than done.

Being able to summon calmness is a real Jedi Mind Trick that comes only with practice.

I had a taste of that when in my first 140.6 (full Ironman length) triathlon, I found myself in 2 ft. chop during heavy rain on a windy lake where one of the rescue boats had capsized and the other ignored or didn’t see my signal for help. My options were limited: turn around and swim for shore and hope I made it.

Believe it or not, having limited options actually reduces the stress a bit.

As I had learned from training in the Spring, swimming just offshore at a local lake during windstorms, I kept my head down, swam deliberately and steadily for the nearest shore, and I didn’t think about anything but “stroke-stroke-stroke-breathe, stroke-stroke-stroke-breathe” until I felt sand under my toes.

What You Can Do to Avoid SNS Overload

In SNS overload, it’s not really possible to just wish away the stress. But you can activate your parasympathetic nervous system with a few focused actions and get things under better control.

Some special forces folks have learned techniques for activating their parasympathetic nervous system in even the most stressful situations — for instance, deep breathing and analyzing your situation and reviewing your choices. I’ve stolen and adapted or added some techniques below based on my experience.

  • Analyze your situation. This helps make you aware of any other wanna-be crises waiting in the shadows. It also helps focus your mind on what your choices are and what resources are available.
  • Dwell in the present. After your planning time has passed, don’t focus on what was done, badly or otherwise, but on what can still be done. This will allow you to adapt instead of getting stuck on a bad decision. There will be plenty of time to review what happened, what was done right, what could have been done better, and actively adapt contingency plans for next time.
  • Focus on what you can control. The simple act of rationally sorting through your options is helpful in reducing stress.
  • Take one rational action. That step doesn’t have to completely remove all stress, but rather give you focus on the one thing you must do to remove yourself from danger.
  • Engage in ritual. Controlled breathing, counting to ten, or any simple non-destructive, non-energy-consumptive behavior that falls into the category of familiar can help. Do something that doesn’t have to do with the crisis, like drinking a little water or munching on a little food.
  • Be still. Especially true when running in a random direction will just get you lost and cost energy.
  • Eat. Unless your problem is a limited food supply, eating tells your body the crisis may be past, since if you were still running from the cheetah, you probably wouldn’t be stopping for a bite.
  • Light exercise. On a run across Texas, that means purposefully switching to walking, not running, for at least a little while — and that doesn’t include pacing nervously. Also a good time to grab a snack!

If you do a little Googling on “activating parasympathetic nervous system” you’ll see prayer and meditation listed also. It’s interesting to me that those specific activities seem associated with stillness, ritual, and a focused mind.

Diabetes, Stress, and Blood Sugar Consequences

Fifteen plus years ago, when I was considerably overweight (50+ pounds) and worked in high-stress jobs first in software / technology and then in sales, my blood glucose would run high no matter how disciplined I tried to be about controlling my type 1 diabetes.

It was only after well over a decade that I learned that it was the stress of the job that not only made me prone to overeating, but elevated my blood glucose and increased my insulin resistance (after all, I was mentally fleeing the cheetah!) and consequently, my weight, as greater amounts of insulin helped me store more and more food energy.

The ironic thing is that if I had stopped self-judgment and anxiety about my weight and taken a few small steps (literally… walking!), I’d have dug myself out of that pit sooner.

Despite the fact that it was 15 years and 50 pounds later, Odessa was no different. I should have focused on mentally and physically healthy behaviors, slowed down, continued to eat, and focused on the one rational thing to do next.

I’ve taken those lessons to heart. I no longer dwell on them except to remind myself of the things to do differently going forward.

I still have good days and bad days. On the bad days, I tend to forget the stuff I just talked about–one indication that I’ve still got a ways to go. On the good days, like when I come in from a training run with a sugar of 101 mg/dl, I feel like I landed a 747 in a snowstorm without even cracking a sweat.

Consciously activating your parasympathetic nervous system can calm you down, keep your mind still, and reduce the sense of panic and non-efficacy that many of us have felt about living with Type 1.

To me it’s worth trying.

With luck, T1D may actually feel a little bit easier to manage.