Two new studies on physical inactivity and its effect on metabolic function

leokitten

leokitten

Senior Member (Voting Rights)
Two interesting new studies on how inactivity can have drastic metabolic consequences.

Take a Vacation From Exercise? Your Body May Not Thank You

This is by no means a suggestion that PWME should be more active, of course adaptive pacing is the best way to go! It just highlights one of the possible downstream effects of having ME.

It is very interesting that physical inactivity can quickly cause metabolic dysfunction, higher blood glucose, and impaired insulin sensitivity in otherwise healthy people. I wonder if it might even be worse in PWME since activity levels are likely much lower.

++ @Silencio on PR for mentioning this article.
 
This is quite astounding. Only 2 weeks?

"The results proved to be consistent if worrisome. The volunteers almost all had developed what the scientists called “metabolic derangements” during their two weeks of being still. Their blood sugar levels had risen, insulin sensitivity declined, cholesterol profiles become less healthy, and they had lost a little muscle mass in their legs while gaining fat around their abdomens".

It took at least 6 years for me to lose a 'little' muscle when I was inactive with M.E. I wasn't exactly 'sitting still' but was lying down most of the day and only getting up when necessary. My LDL, glucose etc were fine.
 
I for one experienced a sudden decrease in muscle mass and subcutaneous tissue after getting ME.

I was an athlete and going to gym or other sport almost daily before getting ME. Resistance training would always result in muscle gain and improvements in tone right up until getting ME.

Right after the sudden flu-like illness and waterfall of symptoms I kept trying to do sport and resistance training. Among other things, I immediately noticed that I could not gain any muscle mass or improve tone.

My muscles basically hollowed out and became strangely soft. This has always been one of my main symptoms. In fact, when I’m doing better I notice my muscles suddenly become more normal, it can change very quickly.

It could be that people who had a high metabolism and lower fat reserves before getting ME would have a more noticeable muscle and subcutaneous tissue loss as the body stuggled to compensate for the sudden cellular metabolic dysfunction, whereas those who already had a lower metabolism and higher fat reserves might not experience this so much.
 
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Interesting that these changes were for people who were still moving around a bit, rather than just staying in bed for two weeks. I've generally reassured myself that, while far from a healthy level of exercise, the activity I am able to do is enough to avoid a lot of the worst problems from inactivity.

There were a few bits of phrasing in that article which made me wonder if they might be slightly dramatising small changes, but I've not looked at the original research.
 
@leokitten . . . I wonder if age is a factor. I don't want to ask how old you are or whether you are male or female (I'm assuming male based on your avatar).

I was in my late 30's during the '5 year mark improvement' from M.E and when I started feeling better I could run again like I was never sick. No muscle loss. Of course this is when PEM started so I was not well but could do an 8km run with no problems.
 
Mij said:
@leokitten . . . I wonder if age is a factor. I don't want to ask how old you are or whether you are male or female (I'm assuming male based on your avatar).

I was in my late 30's during the '5 year mark improvement' from M.E and when I started feeling better I could run again like I was never sick. No muscle loss. Of course this is when PEM started so I was not well but could do an 8km run with no problems.
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I’m male and was 37 yo when I got ME. Like most PWME, I got PEM and everything else right away.

There were a number of people on PR, men, women, different ages, that reported the same sudden muscle tone and subcutaneous tissue loss after getting ME.
 
The studies that the article is based on
Short-term decreased physical activity with increased sedentary behaviour causes metabolic derangements and altered body composition: effects in individuals with and without a first-degree relative with type 2 diabetes.

Abstract
AIMS/HYPOTHESIS:
Low physical activity levels and sedentary behaviour are associated with obesity, insulin resistance and type 2 diabetes. We investigated the effects of a short-term reduction in physical activity with increased sedentary behaviour on metabolic profiles and body composition, comparing the effects in individuals with first-degree relatives with type 2 diabetes (FDR+ve) vs those without (FDR-ve).

METHODS:
Forty-five habitually active participants (16 FDR+ve [10 female, 6 male] and 29 FDR-ve [18 female, 11 male]; age 36 ± 14 years) were assessed at baseline, after 14 days of step reduction and 14 days after resuming normal activity. We determined physical activity (using a SenseWear armband), cardiorespiratory fitness ([Formula: see text]), body composition (dual-energy x-ray absorptiometry/magnetic resonance spectroscopy) and multi-organ insulin sensitivity (OGTT) at each time point. Statistical analysis was performed using a two-factor between-groups ANCOVA, with data presented as mean ± SD or (95% CI).

RESULTS:
There were no significant between-group differences in physical activity either at baseline or following step reduction. During the step-reduction phase, average daily step count decreased by 10,285 steps (95% CI 9389, 11,182; p < 0.001), a reduction of 81 ± 8%, increasing sedentary time by 223 min/day (151, 295; p < 0.001). Pooling data from both groups, following step reduction there was a significant decrease in whole-body insulin sensitivity (Matsuda index) (p < 0.001), muscle insulin sensitivity index (p < 0.001), cardiorespiratory fitness (p = 0.002) and lower limb lean mass (p = 0.004). Further, there was a significant increase in total body fat (p < 0.001), liver fat (p = 0.001) and LDL-cholesterol (p = 0.013), with a borderline significant increase in NEFA AUC during the OGTT (p = 0.050). Four significant between-group differences were apparent: following step reduction, FDR+ve participants accumulated 1.5% more android fat (0.4, 2.6; p = 0.008) and increased triacylglycerol by 0.3 mmol/l (0.1, 0.6; p = 0.044). After resuming normal activity, FDR+ve participants engaged in lower amounts of vigorous activity (p = 0.006) and had lower muscle insulin sensitivity (p = 0.023). All other changes were reversed with no significant between-group differences.

CONCLUSIONS/INTERPRETATION:
A short-term reduction in physical activity with increased sedentary behaviour leads to a reversible reduction in multi-organ insulin sensitivity and cardiorespiratory fitness, with concomitant increases in central and liver fat and dyslipidaemia. The effects are broadly similar in FDR+ve and FDR-ve individuals. Public health recommendations promoting physical activity should incorporate advice to avoid periods of sedentary behaviour.
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https://www.ncbi.nlm.nih.gov/pubmed/29671031

Failed Recovery of Glycemic Control and Myofibrillar Protein Synthesis With 2 wk of Physical Inactivity in Overweight, Prediabetic Older Adults.

Abstract
Background:
Physical inactivity impairs insulin sensitivity, which is exacerbated with aging. We examined the impact of 2 wk of acute inactivity and recovery on glycemic control, and integrated rates of muscle protein synthesis in older men and women.

Methods:
Twenty-two overweight, prediabetic older adults (12 men, 10 women, 69 ± 4 y) undertook 7 d of habitual activity (baseline; BL), step reduction (SR; <1,000 steps.d-1 for 14 d), followed by 14 d of recovery (RC). An oral glucose tolerance test was used to assess glycemic control and deuterated water ingestion to measure integrated rates of muscle protein synthesis.

Results:
Daily step count was reduced (all p < .05) from BL at SR (7362 ± 3294 to 991 ± 97) and returned to BL levels at RC (7117 ± 3819). Homeostasis model assessment-insulin resistance increased from BL to SR and Matsuda insulin sensitivity index decreased and did not return to BL in RC. Glucose and insulin area under the curve were elevated from BL to SR and did not recover in RC. Integrated muscle protein synthesis was reduced during SR and did not return to BL in RC.

Conclusions:
Our findings demonstrate that 2 wk of SR leads to lowered rates of muscle protein synthesis and a worsening of glycemic control that unlike younger adults is not recovered during return to normal activity in overweight, prediabetic elderly humans.
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https://www.ncbi.nlm.nih.gov/pubmed/29095970

I'll leave it to others to critique the science but the one thing I do note is that the first study had 45 participants, the second 22 - cohort size that we would be disappointed with in an ME study.
 
leokitten said:
Resistance training would always result in muscle gain and improvements in tone right up until getting ME.

Right after the sudden flu-like illness and waterfall of symptoms I kept trying to do sport and resistance training. Among other things, I immediately noticed that I could not gain any muscle mass or improve tone
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Same here. I used to be able to tone up to a level that I like in 3 weeks before ME. Since ME I can't tone up properly. When I do try I get severe PEM.

It's as if there is not enough or too much of something there in the muscle to tone up properly and because of that PEM is triggered in the process of trying to tone up.
 
Because aerobic respiration is broken in ME you can't increase fitness in the normal way. It is the mitochondria which drive fitness levels and ours don't work properly.

These studies seem quite dubious to me. The number of participants is very low for a start then a drop in activity level of over 10,000 steps is very drastic while the second group dropped to 991 which is really quite low. I don't manage that many steps, but I don't cook or do housework or go anywhere.

Insulin resistance is not completely understood anyway and 14 days doesn't seem long enough to judge recovery. If the step reduction was done by staying home then the results could indicate what happens with a drop in Vit D.

It would take a longer experiment with many more people to give give the precision that these results are claiming. In general, people who do more exercise have better health results, yes, but these look like scaremongering to me or pushing an agenda - even if you are doing recommended exercise now your disease is obviously caused by being lazy for a fortnight years ago so why should we pay for your treatment.

As an aside, I cannot cut carbs at all, I get hypoglycaemic attacks if I try. I now know it is because the same brain region which doesn't send proper signals to prevent OI is not sending the signal to my liver to release glucose when it is needed. This could be because I have the sort of genetics which lead to diabetes. It was really frustrating to me that as soon as I felt a bit better and did something I would end up sick with hypoglycaemia, grrr.
 
I honestly do not believe these studies are scaremongering, it’s just scientific research. This is how clinical research works in its early stages (where they do not have enough money to do larger, more well-designed studies).

Small cohorts, shorter follow up times, study limitations, etc. These are the first exploratory building blocks towards larger hypothesis testing, which will refute or confirm these results.

Most ME studies have been exactly like this, very small, lots of study limitations, plenty of study design criticism. We should be just as openly critical of them, even if their results align with our beliefs on the disease pathology.
 
leokitten said:
Two interesting new studies on how inactivity can have drastic metabolic consequences.

Take a Vacation From Exercise? Your Body May Not Thank You

This is by no means a suggestion that PWME should be more active, of course adaptive pacing is the best way to go! It just highlights one of the possible downstream effects of having ME.

It is very interesting that physical inactivity can quickly cause metabolic dysfunction, higher blood glucose, and impaired insulin sensitivity in otherwise healthy people. I wonder if it might even be worse in PWME since activity levels are likely much lower.

++ @Silencio on PR for mentioning this article.
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Interesting.

While I think that activity/exercise is essential for the human being, so is resting and recovery. I can't imagine the early human being moved around all day, every day. After finding food I can imagine they lay around, until they had to search for food again.

The article somehow transports the message (that's how I interpreted it) that if you "dare" rest (e.g. for some weeks, which even professional athletes do I think) this is bad for you, even on the long run. I cannot agree to that because it sounds extreme/imbalanced.

Still, I think the consequences of inactivity/lack of exercise are well-known as are the consequences of too much training/activity. As always, balance is the answer.
 
leokitten said:
I for one experienced a sudden decrease in muscle mass and subcutaneous tissue after getting ME.

I was an athlete and going to gym or other sport almost daily before getting ME. Resistance training would always result in muscle gain and improvements in tone right up until getting ME.

Right after the sudden flu-like illness and waterfall of symptoms I kept trying to do sport and resistance training. Among other things, I immediately noticed that I could not gain any muscle mass or improve tone.

My muscles basically hollowed out and became strangely soft. This has always been one of my main symptoms. In fact, when I’m doing better I notice my muscles suddenly become more normal, it can change very quickly.

It could be that people who had a high metabolism and lower fat reserves before getting ME would have a more noticeable muscle and subcutaneous tissue loss as the body stuggled to compensate for the sudden cellular metabolic dysfunction, whereas those who already had a lower metabolism and higher fat reserves might not experience this so much.
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I made this observation, too. It's very hard for me. :(
 
leokitten said:
My muscles basically hollowed out and became strangely soft. This has always been one of my main symptoms. In fact, when I’m doing better I notice my muscles suddenly become more normal, it can change very quickly.
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I wonder if this has to do with glycogen reserves (and the water subsequently pulled in). I remember doing very high rep squats (50+ with just the empty bar) giving me really hard feeling legs within days which dissipated almost as quickly. Have we ever been tested for glycogen storage in skeletal muscle tissue over time or in different circumstances?


Also, since you mentioned a loss of subcutaneous tissue, is there any chance this may be related to stuff regulating water? This would be the first thing that comes to mind which could come and go quickly and we have issues with some hormones and receptors that play into that pop up from time to time, but I do not really understand how any of that works so I can't really tell if this makes a lot of sense.
 
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The alterations observed in the study are trivial and easily reversed as the person resumes their regular routine.

I'd love to be able to exercise regularly (cycling, orienteering etc), but despite trying my own modest exercise program over several years, I haven't been able to increase my ability to that point. I'm sure this is no doubt true for many others.
 
Snow Leopard said:
The alterations observed in the study are trivial and easily reversed as the person resumes their regular routine.

I'd love to be able to exercise regularly (cycling, orienteering etc), but despite trying my own modest exercise program over several years, I haven't been able to increase my ability to that point. I'm sure this is no doubt true for many others.
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This is true, though it's interesting to possibly extrapolate from this whether severely reduced activity over a period of years might result in additional ME comorbidities, which possibly add additional symptoms.
 
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