Sandler et al: Fatigue Exacerbation by Interval or Continuous Exercise in CFS

[mango]

Fatigue Exacerbation by Interval or Continuous Exercise in Chronic Fatigue Syndrome

Sandler CX1, Lloyd AR, Barry BK.

Author information
1 Fatigue Clinic, Lifestyle Clinic, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia;
2 Inflammation and Infection Research Centre, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia;
3 Neuroscience Research Australia, University of New South Wales, Sydney, Australia.

Med Sci Sports Exerc. 2016 May 13. [Epub ahead of print]

Abstract

PURPOSE:
To determine if the typical exacerbation of symptoms in patients with chronic fatigue syndrome (CFS) following a bout of exercise differs between high-intensity interval training (HIIT) or continuous (CONT) aerobic exercise of the same duration and mechanical work.

METHODS:
Participants with specialist-diagnosed CFS performed two 20-minute bouts of cycling in a randomised crossover study. The bouts were either moderate-intensity-continuous (70% age predicted heart rate max (APHRM)) or high-intensity-interval exercise, separated by at least 2 weeks. Self-report questionnaires capturing fatigue and related symptoms, and actigraphy were collected across 2 days before and 4 days following the exercise. Comparisons between exercise bouts were made using paired sample t-tests.

RESULTS:
Fourteen moderately affected participants who were unable to work, but not bed bound, completed the study (9 female, 32 ± 10 years, 67 ± 11 kg). Mechanical work was matched successfully between the exercise bouts (HIIT 83,037 vs CONT 83,348 J, p=0.84). Mean heart rate (HIIT 76 ± 5 vs CONT 73 ± 6 %APHRM, p<0.05) and RPE (6-20) in the legs (HIIT 15.4 ± 1.4 vs CONT 13.2 ± 1.2, p<0.001) were higher for the interval compared to continuous exercise. Mean fatigue scores (0-10) were similar before each exercise challenge (HIIT 4.5 ± 1.8 vs CONT 4.1 ± 1.7, p=0.43). Participants reported an increase in fatigue scores following both challenges (Mean difference: HIIT 1.0 ± 1.3, p<0.01; CONT 1.5 ± 0.7, p<0.001), but these exacerbations in fatigue were not statistically or clinically different (p=0.20).

CONCLUSIONS:
High-intensity interval exercise did not exacerbate fatigue any more than continuous exercise of comparable workload. This finding supports evaluation of HIIT in graded exercise therapy interventions for patients with CFS.

PMID: 27183124 [PubMed - as supplied by publisher]

http://www.ncbi.nlm.nih.gov/pubmed/27183124/

 

[BurnA]

One word : Lloyd.

 

[TiredSam]

One word : Lloyd.

If you say so. I must say a few other words occured to me.

 

[eastcoast12]

If you say so. I must say a few other words occured to me.

That was funny

 

[alex3619]

You might genuinely get these kinds of results under some protocols, and under other protocols get the opposite results. Study design is critical, and I would like to see the details of this one. This is both disappointing and entirely expected coming from Lloyd. Did they even review the exercise physiology studies before designing this one? I will be looking for that in the references and discussion in the paper.

Perhaps someone should tell him that ME is mostly not about fatigue, nor is CFS for the most part. We need to get past studying miasma (swamp miasma causes disease) and blowing smoke up people's rectums (an old therapeutic technique, look it up). I really don't give a damn about fatigue by itself.

 

[Sea]

High-intensity interval exercise did not exacerbate fatigue any more than continuous exercise of comparable workload. This finding supports evaluation of HIIT in graded exercise therapy interventions for patients with CFS.

Anyone else notice they didn't say there was no exacerbation - it just wasn't any worse than their other intervention, so that's ok.

 

[alex3619]

Anyone else notice they didn't say there was no exacerbation - it just wasn't any worse than their other intervention, so that's ok.

Yes, but we only have an abstract. This claim is concerning though as it indicates the same kind of spin you see in other CBT/GET research. The kind like "patients didn't improve in fitness but we think this is swell" or "we proved the null hypothesis but isn't this so nice".

 

[Dolphin]

Participants

Participants (n = 15) were recruited from a specialist tertiary care clinic between August 2013 and February 2015. The Clinic provides a specialised exercise physiology and clinical psychology intervention for patients with chronic fatigue states, as part of an integrated CBT and GET program. Potential participants were informed of the study at the completion of their treatment program by their clinicians, and invited to participate by subsequently making contact with the study coordinator. All participants fulfilled the international consensus diagnostic criteria for CFS (8). Participants were carefully selected based on their level of functioning, so that the dose of exercise in the experiment would be likely to exacerbate their symptoms - in a controlled and time-limited fashion, and would not prevent participation in a second exercise bout after approximately two weeks. Participants were stratified into either a „higher capacity’ or „lower capacity’ group. The „lower-capacity group‟ (n = 1) included those participants who were consistently able to manage 10-15 minutes of walking at a gentle pace without causing a prolonged exacerbation in symptoms (that is an hour or more of worsened fatigue and accompanying symptoms). The „high-capacity group‟ (n = 14) included those participants who were able to manage 20-30 minutes of walking. The capacity level was indicated by the patients‟ treating exercise physiologist.

Eligible participants: had to meet international diagnostic criteria for chronic fatigue syndrome (8); have their treating exercise physiologist and clinical psychologist resolve that they had a stable pattern of symptoms, including optimised sleep-wake patterns, and mood; and be regularly exercising approximately 10-15 or 20-30 minutes walking at a gentle pace without producing a prolonged exacerbation of symptoms. Participants were ineligible if they: were using beta-blockers or other agents known to affect heart rate response to exercise; or had any medical (e.g. lower limb injury) condition that may preclude reliable participation in exercise testing.

8. Fukuda K, Straus SE, Hickie I, Sharpe MC, Dobbins JG, Komaroff A. The chronic fatigue syndrome: a comprehensive approach to its definition and study. International Chronic Fatigue Syndrome Study Group. Ann Intern Med. 1994;121(12):953-9.

This might be a biased of patients group of patients: people who were able to do a graded exercise therapy program already.
---
Later date say:

Although pain is a common co-morbid symptom in patients with CFS, the sample in our study were well characterised patients meeting CDC criteria for CFS, who did not have co-morbid fibromyalgia.

It would be somewhat unusual for no one within a group with CFS to have fibromyalgia also.

---

Results

Participants
A total of 20 patients were approached about participating in the study, 18 of whom agreed while two declined for reasons of injuries and family commitments. A further three were deemed too functional for the study (i.e. would not have experienced an exacerbation in fatigue following the exercise challenge) on closer verbal review of their exercise capacity.

 

[Dolphin]

Pain thresholds have decreased following exercise in in at least 2 CFS studies i.e. people have become more sensitive to pain. So it is (somewhat) unusual that they didn't find that here:

Pressure pain thresholds

There was an overall negligible effect of exercise on pressure pain thresholds, with just one parameter indicator an exercise-induced hypoalgesia in the thigh following HIIT. Unlike previously conducted studies in patients with CFS, our study did not show a hyperalgesic effect of exercise (36, 41). In patients with fibromyalgia, a study comparing high and low-intensity training found that patients‟ ratings of pain increased significantly after the higher-intensity training, as did the number of tender points (37). On this basis, HIIT might have been expected to be the more likely than continuous exercise to reduce pressure pain thresholds, but some evidence for the opposite was observed. A hypoalgesic effect of the exercised muscles following HIIT, but not continuous exercise is consistent with the influence of exercise intensity on healthy adults (25). Although pain is a common co-morbid symptom in patients with CFS, the sample in our study were well characterised patients meeting CDC criteria for CFS, who did not have co-morbid fibromyalgia. It is possible that such patients would have a different pain threshold response to exercise compared with this sample.

 

[halcyon]

So it is unusual that they didn't find that here

Nothing is unusual about inconsistent results between Fukuda studies.

 

[Dolphin]

Exacerbation of fatigue

The pattern and degree of post-exertional exacerbation of fatigue observed in this study was analogous to a previous study of a continuous exercise challenge conducted by our group, which showed a mean FES change score of 1.5 (19). In the current study, all 14 participants experienced an exacerbation after the continuous exercise bout. There was a larger range of responses following the interval exercise, with two participants displaying the opposite effect and reporting an improvement in fatigue symptoms. The variations in fatigue responses may have arisen from the HIIT bout being a less familiar type of exercise compared to the continuous bout where responses were more consistent. This study focused on the magnitude of the exacerbation, but to capture this we had to identify when the peak in fatigue exacerbation occurred, which varied across and within individuals. Importantly, all participants returned to baseline levels of fatigue within the experimental timeframe.

It surprised me that the continuous exercise bout caused a bigger average deterioration in fatigue paired to the high-intensity interval training (1.5 vs 1.0 p<0.001)

 

[Dolphin]

These values equate to exercising at the equivalent of 73.2% APHRM during the continuous challenge and 77.1% APHRM during the HIIT active intervals.

APHRM = age predicted heart rate max

There wasn't a huge difference in the exercise intensities in terms of each predicted heart rate between the 2 exercise groups. That could possibly explain why there wasn't a deterioration in the high-intensity interval exercise group.

 

[Dolphin]

On an individual patient level, the onset of the exacerbation was seen immediately post-exercise in 50% (n=7) of the sample, for both the CONT and HIIT challenges. For the remaining participants the timing of onset of the exacerbation was 1-2 days post exercise.

I found this a little interesting as sometimes there are discussions about whether the exacerbation following exercise or delayed. It varied in this group.

 

[Dolphin]

I remember reading, I think it was in Dr Anne MacIntyre's book, of somebody with ME who relapsed badly and ended up in bed 3 months following running 100m (?) for the bus. I would certainly be cautious of high-intensity activity.

 

[Dolphin]

The order of exercise bouts were randomised but counter-balanced across participants. A minimum of two weeks and a maximum two months between exercise bouts was allowed to ensure that the participant felt their symptoms had returned to „baseline‟ and that their level of functioning was comparable at baseline between the two exercise bouts.

 

[Dolphin]

Participants were asked to conduct normal daily activities throughout the assessment period with no extremes of physical and cognitive activity or inactivity

 

[Dolphin]

A total of 15 participants were enrolled in the study, and all but one completed both exercise bouts. The participant who did not complete the second exercise bout experienced a sustained exacerbation in symptoms temporally unrelated to the exercise challenge. Most participants were female (n=9, 64%), with a mean age of 32.1 years (SD = 10.0). The mean height of the participants was 170.4 cm (SD = 9.8) and mean weight was 66.5 kg (SD = 11.0).

Average BMI = 22.90 kg/m2

 

[Dolphin]

Rating of perceived exertion (RPE) response to exercise challenges

Participants‟ RPE of whole body effort over the entire exercise bout were comparable between the two exercise challenges (MCONT = 13.9, SD = 1.3; MHIIT = 13.7, SD = 1.2, p = 0.62). The same result was seen in participants‟ RPE ratings for effort specifically in their legs throughout the entire exercise time (MCONT = 13.2, SD = 1.2; MHIIT = 13.4, SD = 0.9, p = 0.38). In contrast, the participants reported greater whole body RPE during the active intervals in the HIIT bout (M = 15.5, SD = 1.4) compared to the CONT bout (M = 13.9, SD = 1.3, p < 0.01) (Figure 2A). The RPE rating specifically in the legs was also significantly higher during the active intervals of the HIIT exercise (M =15.4, SD = 1.4) compared to the CONT bout (M = 13.2, SD = 1.2 p < 0.001) (Figure 2B).

One of the most consistent findings in CFS exercise studies is that the rating of perceived exertion in CFS patients is higher than controls for equivalent exercise levels.

My vague recollection of previous CFS exercise studies is that higher RPE levels have very often been found in CFS studies i.e. that the exercise levels here weren't that intense perhaps.

 

[Dolphin]

There was a statistically significant increase in stationary time following the CONT bout, and a corresponding decrease in time spent moving slowly. These differences were not apparent following the HIIT bout. However, there were no statistically significant differences in comparison of the change scores for the two exercise bouts (Mdiff stationary = -3.03, SD = 7.81, p = 0.17; Mdiff moving slowly = 2.46, SD = 7.42, p = 0.24).

 

[Dolphin]

At one point they refer to:

the relatively modest intensity of the HIIT

Although the intensity of exercise was higher in the HIIT bout, the RPE rating of whole body effort expended throughout the exercise period was similar between challenges, as has been reported in healthy subjects (20) and was to be expected with the relatively modest intensity of the HIIT.

Different results might be found with a higher intensity problem.