Today I received a phone call from my doctor saying that my blood work showed a high potassium level and that she wants me to return next week to have another test. She seemed very concerned and asked what I was eating, what vitamins I was taking. I told her that the night before the test I did eat one source of high potassium: mashed potatoes. She said that might be the cause.
I wouldn’t normally be concerned about such test results except that she seemed really concerned. So I looked up some information about high potassium levels. Talk about vague. I read that the effects can range from deadly to no effect at all. That was not helpful, only stressful. And then I saw it could be the result of bad kidneys. Even more distressing is the possibility for heart attack.
This is very strange as I am in otherwise perfect health. I exercise, I eat well, I don’t smoke, I don’t drink alcohol.
But there are many factors that can cause a false positive, such as tightening and relaxing the fist while the blood is being drawn, and that was something I did while the blood was being drawn. So I will retake the test.
Another bit of interesting information that I learned today is that aerobic exercise raises blood potassium levels. Although I was fasting for this test, I went out for an aerobic walk just before I went to have the test. Could that have been a factor? Consider this information from the University of Mississippi Medical School:
In view of the significant influence of potassium on the heart, a decision was made to study the effect of exercise on this important ion in two exercise groups of different intensity. The first group consisted of 44 individuals with known coronary artery disease participating in a supervised cardiac rehabilitation program while the other consisted of 30 healthy joggers. Post exercise mean potassium levels were higher in both groups than resting baseline values. In addition, 5 of 44 participants in the coronary artery disease group experienced major potassium increases of 0.9 mmol/L or more while 7 of 30 healthy joggers experienced this magnitude of increase. Remaining unanswered is the question of whether such abrupt rises in potassium levels in this subset of patients alter their vulnerability to cardiac rhythm and conduction disturbances. A question is also raised as to whether rapid return of potassium levels to baseline post exercise contributes to any risks.
Of greater interest is the healthy control group:
In the other, younger and more healthy group (group 2), there were 30 participants, 6 of whom were women. In this group, the mean potassium level, among 29 for whom analysis was carried out (Table 1), was 4.15 pre exercise and 4.7 post exercise (p = 0.02). Twenty three (77 percent) of the 30 exercisers in this group experienced an increase of at least 0.3 mmol/L. Furthermore, a number of exercisers in this younger and healthier group (group 2) had impressive increases in their serum potassium levels with seven showing increases by at least 0.9 mmol/L in the post exercise sample, constituting a much higher percentage of individuals with a rise than in the group 1 CAD exercise participants (23 percent vs 11 percent). The difference, however, was not statistically significant.
So the question that will be answered next week is this: Is my high potassium level the result of tightening and relaxing my fist, eating mashed potatoes the night before the test, and exercising or is it from kidney failing to eliminate excess levels from my blood?
I’ll let you know as soon as I have the results.
Update one week later: I went in for another potassium level blood test. This time I didn’t eat potatoes the night before the test, I didn’t tighten and relax my fist as the blood was drawn, and I didn’t exercise before the test. The result was normal.
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