Deviations in daily physical activity patterns in patients with CFS (Evering et al., 2011)

[Dolphin]

Deviations in daily physical activity patterns in patients with the chronic fatigue syndrome: a case control study.


J Psychosom Res. 2011 Sep;71(3):129-35. doi: 10.1016/j.jpsychores.2011.04.004. Epub 2011 May 18.

Evering RM, Tönis TM, Vollenbroek-Hutten MM.

Source
Roessingh Research and Development, Post Box 310, 7500 AH Enschede, The Netherlands. r.evering@rrd.nl

Abstract*

OBJECTIVES:

Deviations in daily physical activity patterns may play an important role in the development and maintenance of fatigue in the chronic fatigue syndrome (CFS).

The aim of this study is to gain insight into the objective daily physical activity pattern of patients with CFS in comparison with healthy controls.

The secondary objective is studying the awareness in performing physical activities.

METHODS:
The objective daily physical activity pattern was measured with a tri-axial accelerometer in 35 patients with CFS and in 35 age- and gender-matched healthy controls.

The objective daily physical activity level and distribution of physical activities at low, medium and high intensity levels during the day were measured.

Moreover, variability in performing physical activities within and between subjects was computed.

Subjective ratings of self-reported daily physical activity levels were assessed at a visual analog scale.

RESULTS:
CFS patients were significantly less physically active in the afternoon and evening, and spent fewer activities at high intensity levels and more at low intensity levels.

Moreover, CFS patients showed more variability in their own physical activity pattern during the afternoon.

The heterogeneity in the physical activity pattern between subjects within the CFS and control group did not differ.

Finally, CFS patients were more aware about their daily physical activity level than healthy controls.

CONCLUSION:

CFS patients showed deviations in the objectively measured daily physical activity pattern.

Future research should elucidate the relation between impaired balances in daily physical activity patterns and fatigue severity in CFS.

PMID: 21843746 [PubMed - indexed for MEDLINE]

*I've given each sentence its own paragraph

 

[Dolphin]

The introduction section largely came from a CBT/GET perspective, but I'm not sure the authors really found good evidence for a lot of the theories.

One example where they definitely didn't find good evidence is for this section:

In addition to balancing of activities over the day, awareness
concerning activities is considered important. Several studies indicate
that subjects often misinterpret their own physical activity level
[22,31]. Misperception and a negative self perception in the physical
activity level in CFS patients may cause a distorted physical activity
pattern and possibly have a maintaining role in the course of the
disorder [11,14]. Moreover, to improve physical activity behavior
awareness about inadequate physical activity behavior seems to be an
important aspect [31,38].

Results:

The awareness about someone's own physical activity level was evaluated by
means of the correlation between the objective daily physical activity level and
subjective rating of the daily physical activity level (Fig. 4). Measurements with
objective and subjective physical activity levels at the same measurement day were
obtained in 33 subjects of the CFS group (mean of 952 cpm and rating of 5.6) and 19
subjects of the control group (mean of 1081 cpm and rating of 5.8). The Spearman's
correlation coefficient did show a significant correlation in the CFS group (0.411,
p=0.018), but not in the control group (0.023, p=0.926).

The putative slope for the healthies was actually slightly in the wrong direction!
The authors don't say much about the fact that the issue.

---
The Introduction also says:

Based on this knowledge a focus on physical activities is a key aspect in treatment and considered very essential in learning the patient to deploy a regular and balanced daily activity pattern

While achieving balance is probably good, this makes no mention that basing activity on symptoms can be important - simply doing the same amount every day may not be a good approach.

In the discussion, while focusing a bit more on CBT/GET approaches, they do mention:

Also, Nijs et al. studied the effect of 3 weeks of pacing self-management treatment on the physical activity behavior and health status in CFS patients and found an improved ability to performdaily physical activities, decreased severity of CFS symptoms and improved concentration difficulties,mood swings, muscle weakness and intolerance to bright light [26]. Jason et al. found that helping CFS patients in maintaining expended energy levels at the same level as available energy levels improved physical functioning and decreased fatigue severity [18].

The controls weren't chosen to be sedentary per se, although they had a mean BMI of 26.0

Control subjects were apparently healthy, other inclusion/exclusion criteria for healthy control subjects were: (1) aged between 18 and 65 years; (2) not bounded to a wheelchair; (3) not being pregnant.

Control subjects were recruited by means of advertising in the eastern part of the Netherlands. Care was taken to match the two groups in terms of age and gender, to avoid differences between groups. The body mass index (BMI) was assessed in the control group as an indicator of body composition.

The mean BMI of the control group was 26.0 which indicate a low to moderate
fitness level. The mean objective daily activity level in the control group was 1129
counts per minute; this was equal to the activity level of a group of healthy subjects
(1133 counts per minute; 30 subjects; mean age of 27.1; mean BMI of 24.1) as
measured in a validation study for measuring physical activities with a comparable triaxial
accelerometer, and the activity level of our control group falls into the category of
a moderate physical activity level [4].

The mean daily activity level for the CFS group was 957, 15% less than the control group.
[Aside: it makes the talk of the 50% reduction of activity levels before getting a CFS diagnosis questionable, but then I have often thought that was too strict].

From figure 4, 7 of the CFS patients have higher mean activity levels than the mean for the control mean with 3 being approximately the same.

(comments continued in next message)

 

[Dolphin]

Comments (contd.)

--

The pattern of activity of the two groups across the three time periods is a little interesting:

In the morning, the results are exactly the same (both are 1149 units)
In the afternoon, there is a statistical difference (CFS: 985, controls: 1177)
In the evening, there is also a statistical difference (CFS: 742, controls: 959)

This might suggest that the CFS patients could balance out activities a better by pacing more, and doing less in the morning on average but the authors don't explicitly say that that I can recall.

---
In terms of the relative distribution of hourly activity levels:

The CFS group have 27% at a high activity level, 23% at moderate activity level and 50% at low activity level.

For the controls, it is 42% had high activity level, 23% at moderate activity level and 35% at low activity level.

There was a statistical difference between the CFS and control groups for the high and low activity levels.

Note: low activity levels are not necessarily sedentary levels (that definition wasn't used). Here is what they said about how they set the thresholds. Hourly activity levels is probably not a good way to measure activity intensity. For example, if somebody sprinted, this might show up. Other researchers often used much shorter periods to measure activity intensity.

Activity intensity
The objectively measured activity level per hour expressed in mean acceleration per minute was classified into three categories; high (>1150), moderate (between 900 and 1150), or low (<900). The classification of these levels relied on a validation study performed with a tri-axial accelerometer with the same algorithm as the accelerometer used in this study and also worn at the waist [4]. The number of hours in each category as percentage of the total number of hours in the three categories together was calculated for each group.

---

In the same 33 subjects of the CFS group the correlation was calculated between the objective daily physical activity level and CIS fatigue, and between the subjective daily physical activity level and CIS fatigue. The mean CIS fatigue for these 33 CFS subjects was 49.1 and was negatively correlated with objective and subjective daily physical activity levels (Spearman's correlation coefficient=−0.193 and −0.308 respectively), however, these correlations were not significant.

They say on this

We measured fatigue severity only once, shortly after measuring daily physical activities. Therefore, it is not possible to check for correlations in fluctuating fatigue levels and physical activity levels during the day. It could be hypothesized that CFS patients are less fatigued in the morning and are able to do a lot, but when the levels of fatigue increases during the day the ability to be active decreases. A study by Kop et al. is strengthening this assumption in which increased fatigue severity was associatedwith concurrent and subsequent decreased activity levels [20].

Aside: sometimes researchers assume fatigue is a measure of severity of the illness. However, this ignores the fact that it can also be influenced by the amount of activity a patient is doing, how the illness is managed along with all sorts of other issues e.g. mood, etc.

---
I'm afraid there's one part that I'm not fully sure what it means - but perhaps other people will understand it.

This is from the discussion:

The variability in the objectively measured physical activity pattern within subjects is also significantly different in CFS subjects as compared to control subjects. CFS patients show more variability in their objective physical activity pattern between different days during the afternoon as compared to controls. The variability in the objective physical activity level between subjects was not different between the CFS and control group, meaning that the heterogeneity in the physical activity pattern within groups did not differ between groups.

and

The variability between subjects in the mean physical activity level did not differ between groups. This is in accordance with Van der Werf et al. who did not found significant differences in day-to-day fluctuations between CFS patients and control subjects, however, sub typing of CFS patients based on their physical activity patterns was suggested for improving the success of cognitive behavioral therapy [36].

I probably need to read up on coefficients of variation.

 

[Sparrow]

This is all sort of a "no kidding" to me.

They found out that we're more active in the mornings, and then as the day goes on and we get worn out, we do progressively less. And that some days we feel able to do more and other days we feel like crap and do very little. Also that people with illnesses that result in payback for physical activity pay more attention to their physical activity levels than healthy people. Duh.

The part that gets me about all of these studies is that no matter how they well or not well they set up the experiments themselves, they can look at the results and get the interpretations totally wrong sometimes. They are often not showing what they seem to think that they're showing. And making too many assumptions about cause and effect is just bad science.

 

[ukxmrv]

But are "cfs patients" less fatigued in the morning?That would seem to go against the cortisol tests which show low morning cortisol AM.

In my experience of ME and CFS patients it seems to be more of a pattern of low AM activity and then rising PM. That's why most ME groups have afternoon appointments as more members can make it out of the home then.

 

[Sparrow]

But are "cfs patients" less fatigued in the morning?That would seem to go against the cortisol tests which show low morning cortisol AM.

In my experience of ME and CFS patients it seems to be more of a pattern of low AM activity and then rising PM. That's why most ME groups have afternoon appointments as more members can make it out of the home then.

Weird. I always seem to wake up with a finite tank of energy to spend that day. And I often end up using it up before evening. I'm WAY more symptomatic by evening. But not all patients follow that cortisol pattern either, I guess. I know that mine was high first thing in the morning and then dropped below normal by afternoon, back up to normal by night. Though there also seems to be more to my energy levels than just where my cortisol is. I'm a wreck by nighttime.

 

[Dolphin]

But are "cfs patients" less fatigued in the morning?That would seem to go against the cortisol tests which show low morning cortisol AM.

In my experience of ME and CFS patients it seems to be more of a pattern of low AM activity and then rising PM. That's why most ME groups have afternoon appointments as more members can make it out of the home then.

They measure activity from 8am-10pm. I'm not sure how strict they are but these sort of criteria might mean some types of patients wouldn't have taken part.

 

[Valentijn]

The variability in the objective physical activity level between subjects was not different between the CFS and control group, meaning that the heterogeneity in the physical activity pattern within groups did not differ between groups.

I think they're saying that CFS patients varied from one patient to the next in how active they were. And controls had a similar amount of variation from one control to the next.

So maybe each group had a similar distribution of activity levels, just shifted lower for CFS patients.

 

[taniaaust1]

The pattern of activity of the two groups across the three time periods is a little interesting:

In the morning, the results are exactly the same (both are 1149 units)
In the afternoon, there is a statistical difference (CFS: 985, controls: 1177)
In the evening, there is also a statistical difference (CFS: 742, controls: 959)

This might suggest that the CFS patients could balance out activities a better by pacing more, and doing less in the morning on average but the authors don't explicitly say that that I can recall.

I too are thinking at seeing that result, that it sounds as if most of their patients are over doing it in the early parts of the day rather then spacing their activity over the whole period they are awake and that better pacing maybe should be thought about... I try to keep my activity level at a degree in which I stay fairly stable and not on a downhill slide by each night (unless there is something I MUST do). If a get a downhill slide by the end of the day, know Ive done too much at some point.

I plan ahead for a certain amount of activity in the morning to a level which wont impact me later that day..and then do most of my activity in the afternoon or at night (with every third day a complete rest day as the affects of activity do accumulate after a time otherwise).

 

[peggy-sue]

They have not factored in individual circadian rhythms. This constitutes a major uncontrolled confounding variable and renders the study void.
Quite apart from their peculiar bias on interpretation, ie, subjects are too aware of their activity and paying too much attnention to imagined bodily sensations, rahter than listening to their bodies to know when to stop.

They have not differentiated between aerobic activity and anaerobic activity - another MAJOR confounding variable.

They have not stated if the activity involves climbing or arm raising - or any other specific activity that puts excessive strain on our systems within any of the activity sessions.

It's all just meaningless drivel. Nonscience.

I need a good hour to recover from getting up and dressed and coffee-ing myself and drugging the cat and myself.
I seem to have a peak of physical activity around 4 pm.
I think it's the adrenalin rush that comes from:

"Good grief, he'll be home soon and he can't get at any part of the kitchen (for the mess) to make his tea."

so I have a half-hearted attempt at clearing a bit of space and shoving a few dishes in the dishwasher or clothes in the machine.