Exhaled nitric oxide : changes after high intensive exercise in cold and normobaric climates among healthy adults
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Background: Despite extensively research of the effect of exercise upon fractional exhaled nitric oxide (FENO) little is known about the effect of exercise upon FENO in a cold climate. The primary objective of the present theses was therefore to assess FENO before and after high intensity exercise in two different climates, a normobaric climate compared to a cold climate. Secondly: to assess the changes in FENO during sub maximal exercise and to add more data of exhaled nitric oxide values among healthy subjects according to ATS/ERS guidelines. Subjects and methods: Twenty well trained (58.2 ± 6.6 ml∙kg-1∙min-1) healthy non-smoking, non-snuffing males (n=12) and females (n=8), aged 18-28 (22.8) years were included. They performed three tests; one incremental exercise tests (pretest) in a normobaric environment, temperature (20˚C) and two eight minutes repeated high intensity exercise tests (RET) in a climatic chamber in two different climatic conditions, normobaric (18˚C) (RETN) and cold (-10˚C) (RETC) ambient temperature at random. Ventilation (VE) and FENO were measured before and after the RET and FENO, VE and heart rate (HR) were monitored continuously during the pretest. Lung function measurements (forced expiratory volume in one second; FEV1 and forced vital capacity; FVC) were conducted before and after pretest. Results: The FENO decreased from before (baseline) to after exercise in all three tests and peak reduction was; [mean (± SD)] 30.7 % (±18.3), 28.5 % (±19.0) and 37.3 % (±10.8) in RETC, RETN and pretest, respectively. FENO was lower in RETC after warm up and 20, 30 and 60 min post exercise compared to RETN. The subjects returned to baseline FENO approximately 10 min and 15 min after RETC and RETN, respectively. A reduction in FENO was seen after 20 min and a further reduction was seen 30 and 60 min post exercise in the cold climate. FENO was significantly lower 5 and 10 min post exercise in the normobaric climate. Increased FENO from baseline (online measure) was seen 24 hours post exercise in the normobaric climate. The subjects did not reach baseline FENO values 60 min after pretest. The baseline FENO value was in average 17.2 ± 7.2 ppb, with a 95th percentile of 31.6 ppb. A significant gender difference was seen, with higher FENO values among the males both in baseline and post exercise. Conclusion: FENO is decreased after exercise both in a normobaric and cold climate. A cold ambient climate induces an initial decrease in the FENO values that was reduced until 60 minutes post exercise compared to a normobaric climate. FENO values among healthy males and females aged 18-28 years are 17.2± 7.2 ppb with a 95th percentile of 31.6 ppb.
Masteroppgave – Norges idrettshøgskole, 2010.