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Het "verval" bij

een tweede inspanningstest

is groot en

ME/CVS-patiėnten

kunnen hun inspanning

goed inschatten

(IACFS-ME, 2011)

 

 

 

 


 

 

 

Twee presentaties op de internationale IACFS-ME-konferentie in Ottawa

bevestigen wat veel ME/CVS-patiėnten al lang weten:

  1. Een inspanning wordt duur betaald (studie 1)!
  2. (Veel) patiėnten presteren aanzienlijk minder bij een tweede fietstest 24 uur later.

    De verzuringsdrempel, de inspanning waarbij lichaam over moet schakelen naar anareobe energieproduktie, (vaak) met melkzuurproductie tot gevolg, en

    de inspanning die men kan leveren "zonder te verzuren" nemen met ca. 20% af.

  3. Patiėnten kunnen hun (relatieve) inspanningen goed inschatten (studie 2).
  4. Veel patiėnten halen hun maximale hartslag bij lange na niet,

    waarschijnlijk omdat de arm- en beenspieren voor die tijd al verzuren,

    en toch leveren ze verhoudingsgewijs een "enorme" inspanning

    De hartslag weerspiegelt (correleert met) de inschatting van de inspanning:

De zuurstofopname bij  "de verzuringsdrempel" is de tweede dag zo laag

dat gewone dagelijkse bezigheden als tot anaerobe energieproduktie leiden...

 

Hierbij moeten worden opgemerkt dat het aantal deelnemers relatief beperkt was, maar de eerste konklusie, inspanning pakt negatief uit, is reeds eerder aangetoond (klik hier en hier).

 

 

Voor de syllabus met samenvattingen van alle lezingen, klik op onderstaande afbeelding:

(laden duurt lang, FT)

 

 

 

 

 


 

Exercise testing to quantify effects of fatigue on functional capacity

in patients with CFS.

Keller BA, Micale FG.

IACFS-ME 2011 Conference Syllabus

 

http://www.iacfsme.org/LinkClick.aspx?fileticket=EFIrm%2buCnkM%3d&tabid=142

 

 

Objective:

 

The purpose of this study was to assess

the effects of post-exertional malaise (PEM) on

functional capacity and anaerobic threshold

in subjects diagnosed with chronic fatigue syndrome (CFS).

 

 

Methods:

 

Subjects were

10 females and 2 males (41.3+1.11 yrs) diagnosed with CFS

by a physician experienced in the diagnosis of CFS.

 

To induce PEM, each subject completed a maximum exercise test on a cycle ergometer.

 

A second maximum exercise test was performed 24 hrs later

to assess the effects of exercise-induced PEM on functional capacity.

 

Maximum oxygen consumption (VO2max), maximum heart rate (HRmax),

anaerobic threshold (AT), maximum workload (Wmax),

workload at AT (ATwork), and respiratory exchange ratio (RER)

were measured.

 

RER is an objective indicator of

substrate utilization and subject effort during exercise.

 

 

Results:

 

Significant decreases

from test 1 to test 2 were

13.5% for VO2max (21.5 to 18.6 ml.kg-1.min-1; p<0.01),

8 bpm for HRmax (p<0.01),

18.8% for AT (12.0 to 9.7 ml.kg-1.min-1; p<0.05),

9.4% for Wmax (121 to 109 W, p<0.05), and

17.3% for ATwork (58.3 to 48.2 W; p<0.05).

 

However, there was no change in maximum RER

indicating that subject effort was maximum and also comparable during both tests.

 

 

Conclusion:

 

Results indicate that

PEM decreased maximum functional capacity by more than 13% to below 5 METS;

a level at or below that which is required by many job-related activities and IADLs.

 

To compare,

VO2max in healthy individuals is highly reproducible

over days and even months (r>.95), with a SEM of < 6%.

 

Thus, for subjects in this study,

an expected variation between tests would be ±1.29 ml.kg-1.min-1

in contrast to the observed decrease of 2.9 ml.kg-1.min-1.

 

Furthermore,

PEM decreased AT to below 3 METS

(e.g., light-moderate speed walking),

which is a level of many activities considered to be sedentary in nature.

 

Thus,

completion of sedentary ADLs and IADLs for those with CFS

requires production of energy via anaerobic processes

that will further contribute to PEM and exacerbate symptoms of CFS.

 

Since many daily activities fall into the 3-5 MET range,

individuals with CFS will exacerbate symptoms associated with PEM

simply by completing normal daily activities.

 

 

 

Afkortingen [FT]

 

ADLs: Activities of daily living (ADLs) activiteiten van het dagelijks leven (verzorging).

IADLs: Instrumental activities of daily living, dingen die men dagelijks moet doen om zelfstandig te kunnen leven (zoals eten maken, boodschappen doen, reizen en huishouding).

SEM: standaardfout, de te verwachten boven- en ondergrens (klik hier)

 

 


 

Effort perception in chronic fatigue syndrome is not impaired.

Benjamin M. Larson, Davenport TE, Stevens SR, Stevens J, Van Ness JM, Snell CR.

 

http://www.iacfsme.org/LinkClick.aspx?fileticket=EFIrm%2buCnkM%3d&tabid=142

 

 

Background and Objectives:

 

Activity pacing is one cornerstone of rehabilitation management for CFS.

 

Optimal criteria for pacing are currently unclear, because

patients with CFS may have an impaired ability to self-assess their level of physical exertion.

 

However, this hypothesis has yet to be directly tested.

 

The purpose of this study was to determine

the association between subjective and objective indicators of physical effort

in patients with CFS and matched controls.

 

 

Materials and Methods:

 

Sixteen patients with CFS and 14 age- and sex-matched non-disabled, sedentary individuals

were tested.

 

Each subject received

2 maximal cardiopulmonary exercise tests (CPETs) on a braked bicycle ergometer

that were administered 24 hours apart.

 

Heart rate (HR) was measured continuously and

rating of perceived exertion (RPE) was assessed at each minute

from rest and unloaded cycling until peak exercise.

 

Descriptive statistics (mean ± standard deviation)

were calculated for all dependent variables (DVs),

including peak HR (HRpeak), HR at VT (HRVT), peak RPE (RPEpeak) and RPE at VT (RPEVT).

 

2x2 analysis of variance (ANOVA) was used to assess

the main and interaction effects of group and test on DV measurements.

 

Repeated measures ANOVA was used to assess

group and time main and interaction effects on DV measurements.

 

Pearson’s correlations (r) were calculated

to determine the within-groups associations between HR and RPE during each CPET.

 

Criterion for statistical significance of differences was

 

 

Results:

 

All subjects met standard criteria for maximal effort during each CPET.

 

HRpeak was significantly lower

for patients with CFS (CPET1: 158±15 beats per minute [bpm]; CPET2: 156±17bpm)

compared to controls (CPET1: 182±13bpm; CPET2: 183±11bpm)

on both CPETs (p<.01).

 

HRVT also was significantly lower

for patients with CFS (CPET1: 113±21bpm; CPET2: 111±14bpm)

compared to controls (CPET1: 122±15bpm; CPET2: 131±17bpm)

on both CPETs (p<.01).

 

RPEpeak was significantly greater

in patients with CFS (CPET1: 19.4±1.0; CPET2: 19.6±0.07)

compared to controls (CPET1: 19.4±0.8; CPET2: 18.7±2.1)

on both CPETs (p<.01).

 

RPEVT also was significantly greater

in patients with CFS (CPET1: 13.2±2.5; CPET2: 12.7±2.6)

compared to controls (CPET1: 10.2±2.5; CPET2: 11.2±2.4)

on both CPETs (p<.01).

 

Time series analysis revealed significant group effects for HR (p<.01) and

significant group and group x time effects for RPE (p<.01).

 

HR and RPE demonstrated moderate to high correlation in subjects with CFS

(CPET1: r=.769, r2=.591; p<.001; CPET2: r=.765, r2=.591; p<.001) and

control subjects (CPET1: r=.742, r2=.551; p<.001; CPET2: r=.688, r2=.473; p<.001).

 

 

Conclusion:

 

Subjects with CFS demonstrated significantly greater effort ratings

than control subjects during each CPET.

 

HR and RPE were significantly correlated

in subjects with CFS and matched control subjects.

 

 

Clinical Relevance:

 

The significant association between HR and RPE indicates

patients with CFS can accurately perceive their level of physical exertion.

 

Thus,

patients’ perceptions of physical exertion can be used with confidence

as a basis for pacing self-management programs.

 

 

 

Afkortingen [FT]

 

VT: Ventilatory Threshold (berekende schatting van de verzuringsdrempel/aerobic treshold).

 

 


 

Met dank aan Rob, die me attendeerde op de syllabus met samenvattingen.