My name is Debbie Wright Theriault. I’m a certified personal trainer, a Team Beachbody coach, and a 5 time graduate of P90X. I also have type 1diabetes. Each week, I get emails asking advice on how to manage blood glucose levels while doing the intense workouts of P90X, which combine both cardio and strength training.  In this article, I will share with you my personal principles, my seven rules for success with T1D and P90X, and finally show a week’s worth of my own personal results.

My Principles:

First, let me say that I keep very tight control of my blood sugar levels. My target blood glucose level is 83 mg/dL (per Dr. Bernstein who I follow closely). My last 3 endocrinology appointments have all resulted in an A1C of 4.9% and I’ve been a type 1 for nearly 5 years. I target 83 mg/dL because that is the average glucose level of a healthy, non-diabetic.  I eat very low carb (under 30 carbs per day) and I work out 6 days a week. When your glucose is in range, you just FEEL good, giving me the energy and stamina to WANT to workout and be my healthiest.

I begin every workout with a normal blood glucose under 100 mg/dL in stark contrast to those that get their glucose up to 170 mg/dL just so they can workout, which makes no sense as a blood glucose over 140 mg/dL is already doing organ damage and going that high begins the rollercoaster of highs and lows that takes hours to get control of.

Now, how do I perform such intense exercise with only 30g a day carbs in my diet?  I never fuel up on carbs just to workout. Since I am a type one diabetic, it makes no sense to fuel my body with a source I cannot tolerate.  My fuel of choice? Well, when you eliminate carbs as a fuel source, your body switches and burns fat for fuel so there is no need to ‘carb load’ in order to workout.  Switching to my new fuel source has eliminated roller coaster blood sugars and my numbers stay somewhat steady.

Normalizing blood sugars aids in my ability to workout 6 days a week without adverse effects. During my P90x workouts, I might take a small bolus or two of insulin to try and stay as steady as possible. I may have to make corrections as I go.  I have the Medtronic insulin pump as well as the Medtronic CGM (continuous glucose monitor) which helps me keep close watch during workouts.  By using very small ‘micro-boluses’ and making only small corrections, I get much more manageable blood sugar than eating tons of carbs, guessing at the count and taking huge amounts of insulin at once.  That doesn’t work for me and doesn’t work period.

With my glucose levels in range, and with good tools for blood glucose control, it’s time to work out! As many type ones know there is a different effect from weight lifting and cardio exercise. Weight lifting raises blood sugar and cardio drops it. How to manage? I follow as simple rule and I’ve enjoyed a great deal of success with P90X by keeping that one rule of thumb in mind. When doing P90x, I lift as heavy as possible. This undoubtedly will raise my glucose, I keep watch, take small boluses throughout the workout and maintain a level below 140 mg/dL, and ideally lower, and at the end, I do some cardio which brings my glucose back down again.

With that background in place, let me outline my set of seven rules for success with T1D and P90X.


  1. The Rule of When: Exercise in the afternoon when Dawn Phenomenon is not in effect. Start your workout with a normalized level (70-100 mg/dL).
  1. The Rule of Testing: When working out, test frequently – every 15 to 20 minutes.
  1. The Rule of Blood Sugar Target Always target a normal level of glucose, even if your glucose level is 98, give a small micro bolus to bring you to normal (83). Don’t settle for high glucose levels, there is no reason why a person with type 1 diabetes cannot have normalized blood glucose levels. If your body is used to being at 200 mg/dL, you may feel low at 140 but that is a ‘false low’. False lows very much feel real, but the low is not really low.  It’s just that your body is used to living at 200 mg/dL so you need to train your body to be normal again (this is also true for non-diabetics who are beginning to feel the effects of long term high carb diets and are experiencing elevated, non-normal blood sugars).  You must lower your target a little.  For example, if your target is 140 mg/dL, bring it down to 130 mg/dL for a couple weeks, then to 120 mg/dL for two more weeks, etc. until you’ve reached a true normal.  I promise you, your body will thank you as you’ll feel amazing!!
  1. The Rule of Lows: Always keep glucose tabs handy!! Never treat with food when making small corrections.  Food puts you on the dreaded roller coaster…you over eat and then undoubtedly end up taking more insulin to bring you back down again. If I’m a little bit low, say at 70 mg/dL with insulin onboard, I’ll eat ¼ to ½ of a glucose tab to make the small correction, targeting 83 mg/dL. I take very small amounts of insulin and thus the corrections are small, too.  This is what Dr. Bernstein calls the law of small numbers – the key to predictability and control.
  1. The Rule of Highs: The fact is, if lifting weights, chances are your glucose will rise…it can also rise due to stress hormones etc, you’ll need to correct with small doses of insulin accordingly as you go through the workout. Frequent testing (if you do not have a CGM) will be necessary and you might have some trial and error.
  1. The Rule of Fuel: Eat in a way that allows you take small amounts of insulin. I never take more than 3 units for a meal and my insulin to carb ratio is 1 unit per every 8 carbs. The carbs that I do eat are all from non starchy veggies. This gives me the energy I need to perform my P90x workouts.
  1. The Rule of Grit!: keeping a normal blood glucose is not easy…especially when you add in stress from work, dawn phenomenon and P90x workouts or any kind of exercise for that matter…but it can be done!! You may face some trial and error and that’s okay….just keep working at it. I was frustrated at first…until I learned how my body would react. I knew that glucose levels over 140 were detrimental to my health so I persevered and found a way to make exercise a part of my life without sacrificing my organs. As my very dear friend, Dr. R.D.  Dikeman, PhD once told me “there is never any benefit that outweighs the detriment of glucose levels out of normal range, so strive to avoid them at all cost”.

This is what works for me and my lifestyle. I am a huge advocate of a low carb lifestyle when you have type 1 diabetes – it is the only way to normalize blood sugars.


So let’s see how I did following these rules for the last week. I tracked my P90X workouts and took notes of levels and insulin doses. This is how the week went:

P90x Legs:

  • Starting workout time: 3:00 p.m.
  • Starting glucose of 82 mg/dL with .3 insulin onboard (IOB)
  • Workout midway point: glucose of 98 dosed 1.5 units of insulin through my pump.
  • End of workout: glucose was 147 mg/dL (yikes!!!); I took another 1.5 units directly into the thigh muscle to bring it down faster. (Note: If you hate high blood sugar as much as I do, utilize the intra muscular shot in times like this as it brings down a high very quickly). Legs are always a challenging workout for me blood sugar wise as the muscles are big and cause more of a rise.

P90x Back and Biceps:

      *    starting workout time: 2:30 p.m.

  • starting glucose: 69 mg/dL with .5 insulin onboard.
  • Workout midpoint: glucose is 83 mg/dL  and I dose 1 unit through the pump (as I know its rising)
  • Workout end:  91 mg/dL and rising so I start my cardio and it quickly falls back down.

P90x Chest, Shoulders and Triceps:

      *starting workout time: 4:40 p.m.

  • starting glucose: 87 mg/dL  with 1 unit insulin onboard
  • midpoint:  glucose level of 98 mg/dL  and I dosed another unit of insulin
  • Workout end: glucose level of 111 mg/dL and I have insulin onboard still so I start my cardio and bring it down to the mid 80’s.

P90x Ab Ripper X:

      * starting workout time : 2:50 p.m.

  • starting glucose: 78 mg/dL  with .2 insulin onboard
  • I do not do a midpoint check on this one as it’s only a 20 minute workout.  At the end, my glucose is 99 mg/dL; I take a small bolus and do some cardio.

In conclusion, I feel I deserve to have normal blood sugars before, during and after meals AND ALSO during intense workouts.  By applying the principles and rules listed above, I have had success with P90X, and am in a very positive place mentally, emotionally, and physically.

Hopefully, after reading this article you will realize that you deserve to have normal glucose levels too!  Good luck!

More about the Author:

Debbie Wright Theriault is a contributing author to FITSCRIPT.COM, a certified personal trainer, a Team Beachbody coach, and a 5 time graduate of P90X. She also has type 1 diabetes.  You can reach Debbie at, or find her on You Tube at (