low CO2 blood level

I have had my pacemaker for 6 months.  My PCP ran routine blood tests recently.  My CO2 level was lower than it has ever been.  (17 and and normal range is 20-29)  Average for me has been about 23. All other tests were fine and I feel good. The first 2 months of this year I did nothing for exercise because I was feeling terrible as we determined the heart block diagonosis. I am still building up my stamina so I know I am not to the cardio levels I was last year before problems.

Has anyone experienced low CO2 level as a result of lack of exercise before/after pacemaker implant?
I am hoping as I build up my stamina, this level increases.

I just received these results and will consult with my doctor next week.

I always appreciate the insight from this forum.



Low CO2

by Selwyn - 2022-08-28 07:52:30

In general, a low CO2 is unlikely to be a health problem if your various blood tests are OK ( ie. kindney function, diabetes etc). The body compensates for acid by blowing off CO2 via your lungs. Some medication can cause acidosis. If this applies to you, talk to your prescriber about the effect.

Blowing off CO2 can be the result of hyperventilation eg. anxiety.

A low CO2 is not associated with lack of exercise!  If you are doing strange things with your diet it can affect CO2 levels. 

Your CO2 level is not pacemaker related if you are not short of breath.

low CO2 blood level

by Gemita - 2022-08-28 07:56:41

Bob you clearly say “you feel good” and that your CO2 level was just slightly down from the average lower range.  I wouldn’t be unduly worried but please speak to your team to find out what this means for you personally.  CO2 level changes can be due to a wide range of conditions, from uncontrolled diabetes, hyperventilation to certain meds, to possible kidney and lung issues, so it may need watching but I wouldn’t be unduly concerned about those values.

As you will know, in our body, carbon dioxide controls breathing and maintains the pH of our blood.  Low CO2 levels may indicate problems with acid-base balance in the blood. 

There are many conditions and reasons for a change in CO2 levels.  For example Metabolic Acidosis can cause a decrease in CO2 levels because when the blood is acidic, bicarbonate levels are low and the body responds by increasing its breathing rate.  By breathing faster, more CO2 is exhaled out of the body which decreases CO2 blood levels and ultimately helps bring blood pH back to normal.  This happens to my husband frequently and I often witness him over breathing to help restore his acid balance.  That is just one example of what can affect CO2 levels.

Respiratory alkalosis might occur as well and be a cause too.  Some medications too can potentially affect CO2 levels in the blood (meds like Ace Inhibitors, ARBs, Metformin and others).

Hyperventilation syndrome and anxiety and panic attacks often go hand in hand too affecting acid base balance.  Those with disorders or PTSD often have lower CO2 levels compared to the general population.

I hope your team are able to reassure you that all is well

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