Changes of blood gas results via sports?

Question

Dear ladies and gentlemen,
I have started with regular sports (CF, 42 years old). Since then, my blood gas results have changed:
before:
pH-value 7.40 7.41 100.2
a.CO2-partial pressure [mmHg] 43.10
a.O2-partial pressure [mmHg] 63.50
Standard Bicarb [mmol/l] 26.70
Baseexcess [mmol/l] 2.00
a.O2-saturation [%] 92.55
Hemoglobin [g/lOOml] 15.60
PaO2 std [mmHg] 63.50
a.O2-content [Vol%] 19.54

after 3-weeks of sports:

pH-value 7.40 7.41 100.2
a.CO2-partial pressure [mmHg] 28.50
a.O2-partial pressure [mmHg] 82.10
Standard Bicarb [mmol/l] 21.81
Baseexcess [mmol/l] -4.07
a.O2-saturation [%] 96.42
Hemoglobin [g/lOOml] 15.10
PaO2 std [mlIiHg] 89.52
a.O2-content [Vol%] 19.77

Are the changes of the CO2, O2, Baseexcess und O2-saturation caused by the regular movement?
The values of the lung function improved a few promille.
Many thanks

Answer

Dear questioner,
many thanks for your interesting question, which is however never-the-less not easy to answer.
In general, several well-performed studies were able to show, that regular sportive activities have a positive effect on the lung function. In these investigations, however, the traditional lung function values like FEV1 and FVC have been investigated, not the blood gas values, however. Single investigations could however very well prove, that a single "hour of sport" (20-30 minutes of sport) is able to enhance the oxygen-saturation of CF-patients for at least 30-60 minutes after the strain. This is consistent with our clinical experience, and is interpreted as a sign of opening of single areas of the lung via the sport, which have not participated in the breathing at rest due to e.g. a closure of the bronchi by mucus.
Your blood gas results before and a few weeks after starting a sport-program show a decrease of the C02-partial pressure with an increase of the oxygen partial pressure and the oxygen saturation. These values would be well consistent with an improved gas-exchange, that means a better function of the lung, because of the started sports program. The in the same time only very few improved classical lung function values do not have to speak against this interpretation. However, the baseexcess of -4mmol/l in the blood gas analysis after beginning of the sports program shows a certain "acidosis" of the blood. An aciding of the blood would stimulate the breathing and therefore at least partially explain the lower PC02-values. Has the blood gas analysis probably been taken within 60 minutes after an intensive physical strain, which could then be the cause of this acidosis? A longterm effect of regular sportive strain on the baseexcess has until now not been described for CF patients nor for healthy persons.
I am sorry that I am not able to answer your question conclusively, if the regular movement is the cause of the overall positive changes of the blood gas analysis. The sports program can here at least partially play a role, however does not have to. In any case I would like to encourage you, to go on with the regular movement, as it makes fun, if it is not done too intensively, increases the quality of life and has a positive effect on the capability and lung function. Probably you can encourage also friends to join you?
Yours sincerely,
Prof. Dr. H. Hebestreit

05.10.2010