by Dr. Sheri Colberg, Ph.D., FACSM
With all the exercise training fads out there, it can be hard to navigate the landscape with diabetes. I am frequently asked about the latest training techniques or gym trends, so I want to address a couple of those specifically (CrossFit training and insulin bodybuilding) with regard to whether they’re appropriate and/or advisable for people with diabetes to engage in.
A concerned young man with type 1 diabetes contacted me to ask whether it’s safe for him to do CrossFit training, which is a strength and conditioning program consisting mainly of a mix of aerobic exercise, gymnastics (body weight exercises), and Olympic weight lifting. Its programming is decentralized, but its general methodology is used by thousands of private affiliated gyms. CrossFit, Inc., licenses the CrossFit name to gyms for an annual fee and certifies trainers, but the actual programs vary tremendously from site to site.
His concern about CrossFit arose from reading a blog online by a Paleo diet advocate named Robb Wolf who, in an article about CrossFit training and type 1 diabetes (1), claimed that “We have seen instance of people REVERSING type 1 diabetes with a Paleo diet because they put their autoimmunity in remission.” (That statement alone should make you question this blogger’s credibility.) The young man was already doing and benefiting from CrossFit training and wanted to continue, but Mr. Wolf also blogged that since intense training causes the liver to release excess glucose during training, people with type 1 diabetes “may be better served by mild to low intensity activities. Power Lifting, due to the low volume, might be a good option.”
My perspective is that a young and healthy person with diabetes should be able to engage in CrossFit training without worrying excessively about the transient rise in blood glucose levels that it may cause. To control blood glucose, he or she would simply approach it like any other intense workout, which can cause elevations in blood glucose even with people without diabetes. Insulin users will just need to check their blood glucose frequently and adjust insulin doses to have adequate amounts in their bodies during and following workouts. As a side note, doing some easy cardio exercise after an intense workout can help lower blood glucose naturally in everyone. Also, exercisers will typically experience a bigger rise in the early AM compared to doing the same exact training later in the day (due to having more glucose-raising hormones and less insulin on board in the morning, pre-breakfast).
CrossFit does carry some risks, however. The risk of injury from some of its exercises outweighs their benefits when they are performed with poor form in timed workouts (although there are similar risks from doing other high-intensity programs incorrectly). One concern in particular is that CrossFit’s online community enables athletes to follow the program without proper guidance, increasing the risk of improper form or technique that leads to injury. I have heard of at least one young man who caused significant damage to the cartilage in both of his knees doing such training inappropriately. When undertaken correctly, CrossFit is not inherently bad or ineffective, but beginning exercisers starting such a program may be encouraged to do too much and not be able to discern between training to failure and simply getting a good workout.
By way of example, a young woman who was a physical therapist and a regular CrossFit participant woke the morning after a particularly grueling session consisting of hundreds of reps of arm exercises and found she could not bend her elbows. She was shortly thereafter diagnosed in the emergency room with rhabdomyolysis (“rhabdo” for short), a condition in which damaged skeletal muscle tissue breaks down rapidly. Many other reports of rhabdo related to CrossFit training have surfaced. Strenuous exercise is a known — albeit rare — cause of rhabdo, which can cause kidney failure when breakdown products of damaged muscle cells (myoglobin) are released into the bloodstream (2). Severe symptoms like muscle pain, vomiting, and confusion are indicative of greater muscle damage and possible kidney failure. Severe muscle pain and dark colored urine require immediate medical treatment.
A friend of mine who is a diabetic endurance athlete was once approached by a well-known track and field athlete to see if he could get some of her Lantus insulin. (She said no, of course!) Insulin is an anabolic hormone, meaning that it promotes uptake and storage of fuels from the blood stream, including glucose (into muscle or liver glycogen stores), fatty acids (into fat cells), and amino acids (the building blocks of protein, which are used for muscle growth and rebuilding). From what I know of the concept floating around the bodybuilding world, “insulin bodybuilding” is the practice of using insulin to enhance nutrient uptake, specifically amino acids into muscle to make them bigger. In other words, nondiabetic bodybuilders are using a naturally occurring hormone as a potential ergogenic substance to give them a boost beyond what someone would get normally from effective training and nutrient intake. They’ve tried this before with growth hormone and testosterone, but those are now banned substances in most sports, leading the way for the entry of insulin abuse into sport.
The practice of nondiabetic athletes taking insulin to try to gain muscle mass is potentially dangerous (leading to severe hypoglycemia), and since many of them consume excess carbs to prevent hypoglycemia after dosing with insulin, they can also gain excess fat weight. In someone with diabetes who uses insulin, however, this practice is really nothing more than using appropriate nutrient timing with effective insulin dosing. To be effective at bodybuilding with diabetes, it’s important to keep blood glucose levels in tight control to effectively refuel after workouts, which requires taking just enough insulin to stay in control without getting too low. Some studies show that taking in a bit more protein before and/or after heavy workouts can promote muscle building, although others show no benefit beyond what an individual would get with proper refueling.
A training athlete does not necessarily have to eat much extra protein or take creatine as a supplement, but he or she does need to eat at least 1.4-1.6 grams of protein per kg of body weight (1 kg=2.2 lbs) per day to effectively build muscle. Protein requires some insulin (usually within 3-4 hours of consuming it, just not right away unless eaten with carbs), so exercisers will need to check their blood glucose levels later on after exercise and food intake and dose with insulin if their blood glucose levels start to rise to ensure amino acid uptake into muscle.
- See the questionable blog by Robb Wolf at http://robbwolf.com/2009/08/05/type-1-diabetes-and-crossfit/#sthash.CIZdVMvp.dpu
- Watch a short video by the Mayo Clinic about rhabdomyolysis resulting from workouts: https://www.youtube.com/watch?v=Hy0uEPo8-7w
As a leading expert on diabetes and exercise, I recently put my extensive knowledge to use in founding a new information web site called Diabetes Motion (www.diabetesmotion.com), the mission of which is to provide practical guidance about blood glucose management to anyone who wants or needs to be active with diabetes as an added variable. Please visit that site and my own (www.shericolberg.com) for more useful information about being active with diabetes.
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