Broadbent & Coutts: Graded vs Intermittent Exercise Effects on Lymphocytes in CFS

[Dolphin]

Concluding sentence:

Both GE and IE should be self-paced and undertaken only when the patient is not symptomatic, to reduce the risk of symptom onset.

 

[Sea]

Minor point:
There are other interpretations for some of the findings apart from deconditioning. But I suppose it is not unreasonable to mention it has one possible reason for some findings.

Suzanne also believes that the drop in function on a second day CPET can be attributed to deconditioning.

 

[Sea]

Time since diagnosis for CFS participants was 2.9 ± 2.6 yr. Pre-intervention self-reported fatigue severity scores ranged between 15.8% (very low) to 100%

Hmmm, does this mean the range of time from diagnosis for the patients was 3 months to 5 years and 3 months?
If it does I guess they left my results out of the study.

 

[ash0787]

Initially this looked great, the type of study I want to see, however on closer inspection it doesn't make much sense to me .... " Twelve weeks of GE and IE training significantly improved CD4+ lymphocyte activation and aerobic capacity without exacerbating CFS symptoms. "

CFS patients cannot exercise without increased symptoms unless it is done in a very specific way and even then the negative consequences can be long term rather than immediate, and why is immune activation considered an improvement, in the context of Ritux studies suggesting an autoimmune aspect of the illness ?

 

[Snow Leopard]

The rates of compliance were high. However it is unclear to me whether the figure of 89% includes the people who withdrew.

Compliance to what? Showing up?

We don't have actigraphy data.

 

[Sean]

Both GE and IE should be self-paced and undertaken only when the patient is not symptomatic, to reduce the risk of symptom onset.

Oh, FFS! This is descending into Dadaist farce.

 

[arewenearlythereyet]

I don't get what level of exercise they were doing? Was this actually aerobic exercise? They say they set a baseline. What if the baseline was very low and below their aerobic threshold? If the cohort were only mild cases this would be achievable by pacing their day? I can do 20 min walking a day properly paced 4 days per week. If I carry on for 40 min my heart rate goes too high and I crash. If I run for 2 minutes I crash...bad. My 20 min walk gives me approx 15.6 VO2 (calculated) vo2 max for this is 16.5. A normal much younger man would have a measured VO2 max of 41. It's quite possible that the exercise was just paced non aerobic activity and they are using VO2 max to infer that it was. Perhaps the data is in the report?

 

[Sea]

Compliance to what? Showing up?

We don't have actigraphy data.

No, no actigraphy data. I repeatedly told my supervisors that I was doing less and less activities of daily living in order to do the exercise. My exercise capacity did not increase over the 12 weeks and functionally I went backwards.

My fitness did improve so my 1st day CPET results at the end of 12 weeks were somewhat better but a 2nd day CPET also at the end of the study revealed significant drops in VO2 max and the other measures too.

 

[Sea]

I don't get what level of exercise they were doing? Was this actually aerobic exercise? They say they set a baseline. What if the baseline was very low and below their aerobic threshold? If the cohort were only mild cases this would be achievable by pacing their day? I can do 20 min walking a day properly paced 4 days per week. If I carry on for 40 min my heart rate goes too high and I crash. If I run for 2 minutes I crash...bad. My 20 min walk gives me approx 15.6 VO2 (calculated) vo2 max for this is 16.5. A normal much younger man would have a measured VO2 max of 41. It's quite possible that the exercise was just paced non aerobic activity and they are using VO2 max to infer that it was. Perhaps the data is in the report?

Each person's level of exercise was tailored to what they could do although there was a recommended start point. The VO2 max was determined by a CPET at the beginning of the 12 weeks and again at the end.

I don't understand what you mean by your calculated VO2 max with your walk.

 

[arewenearlythereyet]

Each person's level of exercise was tailored to what they could do although there was a recommended start point. The VO2 max was determined by a CPET at the beginning of the 12 weeks and again at the end.

I don't understand what you mean by your calculated VO2 max with your walk.

Ahh so it's possible that people were not always exercising aerobically?

I'm trying to get an understanding of how vigorous the exercise was and whether it was above or below the individuals aerobic exercise heart rate zone. I used the calculated VO2 for my walk from here:

http://www.runnersweb.com/running/rw_news_frameset.html?http://www.runnersweb.com/running/vo2.shtml

this assumes that I keep my pace consistent and is no way as accurate as a CPET, just used it to illustrate. The figures came out as:

Distance

• 1.300 miles
• 2.092 km
• 2288 yds

Time
0:20:00
Velocity

• 1.743 m/s
• 3.900 MPH
• 15:23 per mile
• 9:33 per km

VO2 at this pace
15.60 ml/kg/min (95.3% of max)
VO2 MAX
16.37 ml/kg/min
VO2 and percent_max based on "Jack Daniels, Conditioning for Distance Running - The Scientific Aspects", Wiley & Sons, 1978. The formulas used are:

• Percent_max = 0.8 + 0.1894393 * e^(-0.012778 * t) + 0.2989558 * e^(-0.1932605 * t)
• VO2 = -4.60 + 0.182258 * v + 0.000104 * v^2
• VO2 MAX = VO2/percent_max

where t is the race time in minutes, and v is race velocity in meters per minute.


I would hardly call my walk a race though and I am very careful not to walk too fast so as to " go aerobic". I find that I do have to cut other things out in the day to do this walk like you said earlier and have to drop it entirely if other things take priority. I wondered whether the test took this into consideration? It looks like it didn't.

I think If the research didn't consider the pacing implication, this study could easily be taken out of context. If the exercise just takes energy away from say cooking a meal or having a shower, how helpful is it? And how fit do you stay just by doing those things within your energy envelope I wonder? and what about those that don't even have enough daily energy to do those things?

Sorry for the detail....I try and keep it brief generally but this sometimes causes confusion.