Metformin Interferes With Exercise: A Catch-22

If you are on prescription metformin and you are initiating an exercise program . . .

Bravo to your efforts! Exercise works better than metformin to control blood sugars, and metformin interferes with exercise performance.[i]  The energy you use during a sustained workout is funded in large part by free fatty acids in your bloodstream, metformin decreases this compound by 10-20%.  Subjective fatigue was greater in those on metformin and heart rate was higher than usual on metformin.  Researchers therefore absurdly suggested, “people on metformin might need to workout less strenuously.”[ii]

Strenuous exercise is exactly what will cure the problem without the drugs.

Therefore, since regular strenuous exercise improves insulin resistance better than metformin,[iii] adjust the latter.  I hate to say it, your your doctor will be reluctant to reduce your metformin because he/she assumes that you are more likely to stick with popping a pill rather than persisting with an exercise routine.  So even though exercise is a superior therapy, the medical advice you will likely receive will be based upon your presumed failure.  Your success is up to you!

So why has this errant medication become the ubiquitous “go-to” drug for type 2 diabetes, and precursor conditions? It is because the medical institution has narrowly defined the problem as high blood sugar. That’s it. Not insulin resistance, but high blood sugar. There are other drugs that increase insulin (sulfonylureas I have written about earlier) and thereby dramatically lower blood sugar, but in studies, people taking these medications tended to die more readily.[iv] So metformin, which doesn’t overtly kill people, has become the preferred drug. Low expectations if you ask me.

Throughout the Blood Code, I’ll continue to encourage you to take the steps that move you away from insulin resistance and toward insulin sensitivity. As you include more strenuous exercise, following the Fitness Principles from The Blood Code into your day and week, you will need to discuss adjustments and reductions in metformin dosage with your doctor. Check your results and progress with the Progress Panel within a few months.


[i] from the Diabetes Prevention Program: US National Institute of Health.

[ii] Normand G. Boulé NG, et al. Metformin and Exercise in Type 2 Diabetes: Examining treatment modality interactions. Diabetes Care. 2011 July; 34(7): 1469–1474.

[iii] Orchard T, et al. The effect of metformin and intensive lifestyle intervention on the metabolic syndrome: the Diabetes Prevention Program randomized trial. Ann Intern Med. 2005 Apr 19;142(8):611-9.