Volgens een presentatie van Katarina Lien op de recente IACFS-ME conferentie
is de zuurstofopname tijdens een inspanningstest sterk verlaagd in ME/CVS-patiŽnten,
maar neemt-ie de tweede dag (bij de tweede inspanningstest) nauwelijks af.
Wel zijn de lactaatniveaus sterk verhoogd en neemt dat probleem de tweede dag (sterk) toe.
Lactaatniveaus weerspiegelen de mate van anaerobe (zuurstofloze) energieproductie.
Blood lactate increases more rapidly after a previous exercise challenge in patients with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) than in healthy subjects.
IACFS/ME Conference, 2016 October 27-30. Fort Lauderdale, Florida.
Lien K, Johansen B, VeierÝd MB, Haslestad AS, Melsom MN, Kardel KR, Iversen PO.
Previous findings from repeated cardiopulmonary exercise testing (CPET)
suggest that exercise on day 1 negatively influences peak oxygen uptake (peak VO2)
on day 2 in patients with CFS/ME.
Accumulation of lactate denotes a transition to anaerobic glycolysis,
a limiting factor on maximal performance.
The main aim was to examine the effect of an exercise challenge on
peak VO2 and lactate accumulation in CFS/ME patients performing CPET on two consecutive days.
Eighteen female patients (18-50 years) fulfilling
the Canadian Consensus Criteria and the International Consensus Criteria for CFS/ME and
15 controls (healthy, sedentary women; 18-50 years) performed two CPET 24 hours apart.
We measured oxygen uptake and collected arterial blood samples for lactate analysis
at baseline and every 30th second during the tests.
Two-sample and paired t-tests and mixed model analysis for repeated measurements were applied.
Lactate levels per work rate were higher in patients than in controls
on both test days (p interaction<0.001).
Furthermore, lactate accumulation on test 2 occurred earlier in the patients,
and later in healthy subjects,
compared to their respective lactate accumulation on test 1 (p interaction<0.001).
At test 1, mean (SD) peak VO2 (ml/kg/min) was lower in patients than in the controls
(24.2 (4.9) vs. 36.6 (6.2), p<0.001).
Mean difference in test-retest peak VO2 was -1.4 (1.1) among the patients (p<0.001),
whereas no change was found in the controls (-0.9 (1.8) p=0.07).
However, the mean test-retest difference in peak VO2 did not differ between the groups (p=0.33).
CFS/ME patients have a higher lactate level than heathy subjects
at baseline and per work rate on both tests.
the first exercise test seems to induce an earlier lactate accumulation in patients,
when retested the next day.
This is not the case in healthy subjects.
Furthermore, this study confirms that
CFS/ME patients have a decreased physical capacity compared to healthy subjects,
but the change in peak VO2 after repeated CPET
did not discriminate between patients and healthy controls.