Elevated Blood Urea Nitrogen From Training?

My physical 6 months ago showed an elevated BUN level (34, should be 20 or less) which is normally used to test kidney function. My doc explained that dehydration, high protein intake, and high intensity exercise can all contribute to an elevated BUN level. After 10 days of easy spins and reduced intensity in the gym my BUN dropped to 21.

Last week I had my BUN checked again and it was back up to 30. Of course I’ve been doing plenty of high intensity bike workouts as part of my polarized plan as well as a couple hard training days in the gym each week. Also eating a fairly high protein diet.

My question to all you other training masochists out there is have you experienced similar issues with your blood urea nitrogen levels?

There are any number of lab values that would be elevated or seriously aberrant per the usual “normal ranges.”

Lactate, troponin, and pro-BNP, also some echocardiographic measures, can be seriously whack after hard athletic efforts.

On the other hand, other lab values should basically always be maintained in the normal range. Sodium for example.

But none of this is anything you really need to be concerned about, as long as we’re talking about the context of usual athletic training and competition.


  • a doctor but not your doctor