Author Topic: chronotrope incompetence and not finishing LEL  (Read 4755 times)

chronotrope incompetence and not finishing LEL
« on: 02 August, 2017, 09:05:42 pm »
Hellymedic kindly noted in the LEL thread that I had not finished.  I thought this would be the best place to make some comments:

I have trained for LEL for the last 12 months with a coach and several sessions a week on the turbo. So why do I not feel upset that I had to pull out at Moffat?

I started at 13:45 but had not slept well for the last 3 nights due to work pressures and excitement/worry.  This relative sleep deprivation may be relevant.

My plan had always been once I knew my start time  to ride through the night to the Humber Bridge and then stay at the Premier Inn (100m off route).  I have been on a strict LCHF diet for about 18 months now and suspected that the controls would be highly carb orientated (that is not a criticism just a reality) so was not worried about bouncing controls which I did fairly well with just a cup of tea and waterbottle refills at the first 3. Louth was brilliant with 3 chicken legs.  The Premier Inn was chosen for a full LCHF breakfast. As background I will generally ride a 200 with a couple of babybel in my bag and eat one of them.  I may have a coffee.

I made the Humber bridge ahead of schedule with an average HR of 134bpm and average power of 124W.  I had blatantly wheel sucked anybody who didn’t seem to want to share and I was pulled by a very strong Brazilian rider for 2 hours who had a broken Garmin.

3 hours sleep and a rather poor breakfast I set off again.  I do not like the Howardian hills but was going steadily although in retrospect the problem was beginning to appear.

At barnard castle I had amazing chilli but thought the problem was that the legs were a bit tired so opted for a couple of hours to let them recover before Yad Moss.

I set off for Brampton and found that I could put out normal power for a couple of minutes but the HR would not rise commensurately which was very strange.  I was left riding the hill at about 2/3 of what I had expected.

I dropped down into Alston and found myself shivering constantly for the next 2 hours even in a blanket and lying on a lilo in a warm room.

I then set off for Brampton and had some breakfast before heading onto Moffat.  My thoughts were that the flat of the route would let me get back to what I had done on day 1 and regain some time which I had lost.  I crawled to Moffat and phoned home.  This was weird.  (Remember this is not at this stage really particularly new territory in terms of distance especially as in retrospect it started about Pocklington which was only at about 400km.)

Having talked to my wife about the situation I decided to test myself up the Moffat climb which is 10km of 5% climb and then 50 miles of no mobile phone signal.  At this time I had no breathlessness, no pain, my legs felt great – I just knew that my HR was not responding when I tried to up the power.  Worth remembering that as a geek I have power and HR data on every ride have done for the last 4 years so I know what my HR is for any given power pretty much and what the drift will be with fatigue. (that is not to say that I am uberfit, just have a lot of data)

Heading up the hill I tried to do about 220W which I should be able to do even tired for about 10minutes at a HR of 140-150.  I started at a HR of 120 and it rose to 127.  The legs started to feel as if they were going into lactic acidosis.

I thought of possible problems on a moor with no phone coverage and turned round, quit and found the local GP.  ECG and blood sugar very quickly done about 2 hours after stopping riding.  My blood sugar was 4.2.

ECG showed t wave inversion, right bundle branch block and pre-excitation – possible ischaemic related changes!!

On balance of probability probably not but best safety call was a blue light to Dumfries Royal Infirmary.

I have to say that the care from Dr Crosby in Moffat, the paramedics, the A&E team and all the staff in Dumfries was nothing less than outstanding to this unshaven smelly, guy who walked in off the street.

By the time I arrived on the ward my ECG changes had reversed and my troponin was 24.  They did do a second one and a D-dimer but I did not get the results. Obviously they were not worried.  I spent the night in the hotel and went back this morning for a chat with the cardiologist.

In discussion (and my reading) the ECG changes are probably associated with endurance exercise and whilst the cardiologist suggested changing my lifestyle the reality is that endurance athletes live longer and the changes reversed within a few hours.

The interesting bit is the chronotrope incompetence.  This is the inability to raise your HR in response to physiological demand and is usually a sign of illness.  However it is frequently seen in hypoglycaemia and so is shivering.  I have been unable to find any information as to the order of these events and relevant glucose levels.

Also the heart normally runs on free fatty acids (FFA) and only switches to glucose for exercise.  Therefore theoretically relative hypoglycaemia would become more important in prolonged exercise.

Now as someone on pure keto my glucose requirements are provided by gluconeogenesis so if my gluconeogenesis could not keep my blood sugar above 4 whilst exercising then chronotrope incompetence (and the shivering) could be the bodies first safety cut out response.

So where am I at the moment?  All of my training delivered me to the start line in a position where I could produce the power and the HR to do LEL in about 110 hours.  All of my equipment worked perfectly.  No saddle problems or pudendal nerve problems, no numbness in the hands and no feet problems (all of which had affected me in the past).

All my lights and garmin worked flawlessly.

Bike and tubeless tyres worked perfectly. 4 punctures that I heard which all self sealed.  The Schwalbe Pro ones though may be a bit soft for everyday use to get three punctures in one tyre (the other was a Hutchinson)

So I was ready and able.  I was stopped by a completely unforeseeable problem. Not my fault.

So whilst I did not finish I achieved my aims for the year in a very real sense.

What will I do in the future?  I will add in some chocolate or other carbs when I am riding over 300-400km to keep my blood sugar higher but I will keep on with the keto diet as the advantages outweigh any other diet for how I want to live my life. I will also be aware of a possible problem much earlier.  I may also find an endocrinologist or exercise physiologist

hellymedic

  • Just do it!
Re: chronotrope incompetence and not finishing LEL
« Reply #1 on: 02 August, 2017, 09:23:18 pm »
Food for thought!
The input of an exercise physiologist would be helpful.
I also ponder whether military and expedition type physicians might have thoughts or experience.

I also don't know how much data and experience the pundits have with people of our age group.

Re: chronotrope incompetence and not finishing LEL
« Reply #2 on: 02 August, 2017, 09:40:56 pm »
Helly, I know.  I cannot find a single reference to this in the medical literature but I suspect it is real if you are on a keto or 5:2 fasting type diet.  I would love to know what the Zulu warriors to whom this was a stroll in the park did. Is gluconeogenesis trainable in the liver? who knows as nobody would be interested in doing a study.  And how many lab rats could you make exercise for that amount of time to get data.  No ethics committee would approve the study.

hellymedic

  • Just do it!
Re: chronotrope incompetence and not finishing LEL
« Reply #3 on: 02 August, 2017, 11:10:32 pm »
I'm not sure LEL would be a 'walk in the park' for any sub-group. Few groups have constant levels of moderate exertion. Exertion is intermittent for many.

Death Marches in WWII killed many. They were submaximally exerting on scant nutrition. This is NOT a model to emulate!

Re: chronotrope incompetence and not finishing LEL
« Reply #4 on: 03 August, 2017, 12:20:50 am »
Hi Chris

Thanks for an interesting update and sorry you had to stop - although it sounds very clearly like the best decision.

Your analysis and data is interesting. I think that Helly has possibly hit a nail on the head with her comment on scant nutrition. As I read your factual report, I was struck by how little you ate.

Also, a HR of 134 is probably higher and more intense than during the death marches Helly noted. I'm always struck that, even though riding with no food for 100kms seems pretty easy at a moderate pace, there is a real depletion afterwards. On LCHF you probably feel this less than I do as your body presumably doesn't rely on glucose in every day low intensity activity. But, the energy has still been used and you'll either need to replenish or lose weight.

Perhaps too, pushing some hills at 220W also depletes your glucose stores faster than you can replenish without carbs. I also recall reading somewhere that glycogen storage in LCHF diets was up to 2/3 of that in higher carb diets.

Anyway, interesting case study and I hope that you are fully recovered now?

Mike

Re: chronotrope incompetence and not finishing LEL
« Reply #5 on: 03 August, 2017, 09:42:15 am »
I've had several situations in the past where no matter how hard I pushed, my heart wouldn't 'go' any harder. These happened when I was young as well as in later years, so nothing to do with age.

Strongly suspect it is something to do with supply of energy - I really know nothing about this. Happened when working outdoors on the farm, literally working to exhaustion over a period of maybe 8 hours and despite limbs feeling like they could go on, heart wouldn't pump.

Had it when trying to deal with a flood a few years back. No matter that I'd eaten food and my muscles didn't feel exhausted, I had no strength to do work. Could have laid on the ground and just given up life feeling, despite doing what was heavy labour, my heart was just plodding along.

You said that the heart 'runs' on glycogen; is it possible for the *rate* of supply of glycogen to the heart to drop too low to sustain high level work?
<i>Marmite slave</i>

Re: chronotrope incompetence and not finishing LEL
« Reply #6 on: 03 August, 2017, 09:59:13 am »
Not really glycogen but pure glucose. I think this is the problem. If a person (farmer)used to running on real food so probably fairly Keto adapted, is unable to generate enough glucose to maintain their blood glucose level then this will happen.

All the normal ranges are for "normals" and a definition of hypoglycaemia of 4 is perhaps too low   Mine was 4.2 and then 4.5 which nobody paid any attention to because you do blood sugar to look for diabetes not hypoglycaemia.

Re: chronotrope incompetence and not finishing LEL
« Reply #7 on: 03 August, 2017, 10:07:47 am »
You guys clearly know much more about this than me. But I would make the point that getting to your "failure" point is much further than 95% of the population could achieve. Well done! and am sure you will do even better next time.

hellymedic

  • Just do it!
Re: chronotrope incompetence and not finishing LEL
« Reply #8 on: 03 August, 2017, 11:24:24 am »
I suspect the actual blood sugar level can be OK at 4 or so but the issue is the rate of supply from food and reserves.

Someone can be iron-deficient with a normal serum iron. Iron-binding capacity then becomes the critical diagnostic variable.

So the 'current account' shows a satisfactory level but the deposit account is empty and there is little income.

the JAM (just about managing) blood sugar scenario. Resting blood sugar is OK but expenditure > income and Budget Manager say No Faster...

Re: chronotrope incompetence and not finishing LEL
« Reply #9 on: 03 August, 2017, 11:36:28 am »
Sorry to read of this.

Are you being referred to a cardiologist locally? It might be worth thinking about an echo and / or MRI, perfusion scan and perhaps a Holter monitor.

T42

  • Apprentice geezer
Re: chronotrope incompetence and not finishing LEL
« Reply #10 on: 03 August, 2017, 11:42:02 am »
I suspect the actual blood sugar level can be OK at 4 or so but the issue is the rate of supply from food and reserves.

Someone can be iron-deficient with a normal serum iron. Iron-binding capacity then becomes the critical diagnostic variable.

So the 'current account' shows a satisfactory level but the deposit account is empty and there is little income.

the JAM (just about managing) blood sugar scenario. Resting blood sugar is OK but expenditure > income and Budget Manager say No Faster...

Makes sense to me. The only time I've ever experienced real, crushing hypoglycaemia was just after my first stent, when I was following the dietician's advice to the letter.  I'd only got 35k from home, too.  And yes, I had told her I was a cyclist. At least I got a yardstick out of it, on both hypos and dieticians.

Anyway, heartfelt sympathy for the DNF, Chris, and the whole alarming experience.
I've dusted off all those old bottles and set them up straight

Re: chronotrope incompetence and not finishing LEL
« Reply #11 on: 03 August, 2017, 11:50:03 am »
I suspect the actual blood sugar level can be OK at 4 or so but the issue is the rate of supply from food and reserves.

Someone can be iron-deficient with a normal serum iron. Iron-binding capacity then becomes the critical diagnostic variable.

So the 'current account' shows a satisfactory level but the deposit account is empty and there is little income.

the JAM (just about managing) blood sugar scenario. Resting blood sugar is OK but expenditure > income and Budget Manager say No Faster...

Sounds reasonable. Given the current increasing trend of your blood glucos after stopping - 4.2 at 2 hours and then 4.5 sometime later - it's conceivable that the level during exertion dropped below 4 and caused the 'governor' to intervene. A very reasonable negative feedback loop given the potentially serious consequences of a deeper hypo.

Mike

hellymedic

  • Just do it!
Re: chronotrope incompetence and not finishing LEL
« Reply #12 on: 03 August, 2017, 12:21:31 pm »
I am not keto adapted.
I have failed to push my heart rate over 120 on a skipped breakfast morning commute. (and had previously topped 190 on a short trip to work)

Re: chronotrope incompetence and not finishing LEL
« Reply #13 on: 03 August, 2017, 01:28:22 pm »
That's quite persuasive, even as a sample of one. I'm not Keto  adapted either, but am happy enough riding 50 miles before breakfast on Saturday mornings.

Mike

Re: chronotrope incompetence and not finishing LEL
« Reply #14 on: 03 August, 2017, 02:35:08 pm »
I think the shock was it starting at around 500km when I have not previously had problems unto the 400 point on exactly the same nutrition.

I am quite enjoying the research into this and am trying to find my most interested cardiologist this afternoon.  I have a couple of young colleagues who may be interested or know somebody who would be in Nottingham or Leicester.

hellymedic

  • Just do it!
Re: chronotrope incompetence and not finishing LEL
« Reply #15 on: 03 August, 2017, 02:42:51 pm »
Whole body potassium needs to be grossly depleted before blood potassium levels drop significantly.
Potassium and glucose travel together through cell membranes under the influence of insulin.

I am no physiologist and I am thinking aloud...

Re: chronotrope incompetence and not finishing LEL
« Reply #16 on: 03 August, 2017, 04:01:25 pm »
I think that cardiac muscle is a little odd in its glucose transport mechanisms.  I am not sure if the potassium link is as clear.  I use Nuun tablets in every bottle and was peeing absolutely clear throughout having drunk more than usual on purpose.  Whilst i did not specifically look at my U&Es there was no comment.
Chris

ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: chronotrope incompetence and not finishing LEL
« Reply #17 on: 04 August, 2017, 01:47:13 pm »
<3.5 is technicaly hypolgycaemia. So your 4.5 is absolutely fine and I would not be worried about that at all if I saw that myself mid ride.

I let mine elevate, ideally less than 10 pre ride by lowering my insulin pump rate, testing regularly and having small amounts of carbs regularly, typically 20g/hr.  I've seen readings as low as 2.9 which theoretically should have me on the floor, buut whilst exerciseing give me no other symptoms in addition to the normal sweating, elevated HR and appropriate breathing rate.  Non-exercise related hypos are nasty and give me the shakes, light headedness and mental confusion as well.

I'm LCHF other than during exercise as well, adn try to keep my HR<145 for steady efforts, let it get up to about 160 on the hills.  One thing you could try, which a lot of keto adapted athletes find is that you need a little carbs during exercise. As I understand it you neeed it to keep both fat burning and carb burning metabolism in parallel, although the fat burning can predominate with suitable training which it sounds like you have.
“Procrastination is the thief of time, collar him.” –Charles Dickens

Re: chronotrope incompetence and not finishing LEL
« Reply #18 on: 04 August, 2017, 01:58:20 pm »
I think the shock was it starting at around 500km when I have not previously had problems unto the 400 point on exactly the same nutrition.

I am quite enjoying the research into this and am trying to find my most interested cardiologist this afternoon.  I have a couple of young colleagues who may be interested or know somebody who would be in Nottingham or Leicester.

Fascinating as all this keto and glucose transport stuff may be, given the ECG changes and slight troponin rise it might be the case that a cardiologist would want to rule out ischaemia or other pathologies. Unlikely, I know, given your usual exercise capacity and absence of classical symptoms but nevertheless.

Re: chronotrope incompetence and not finishing LEL
« Reply #19 on: 04 August, 2017, 02:23:48 pm »
I agree with getting the investigations.  One advantage of being in the profession is that i have an appointment booked on a PP basis with a colleague in the next few days and then any tests on the NHS if indicated.  I also have made contact with probably the leading authority on this in the country and look forward to hearing his views.


Re: chronotrope incompetence and not finishing LEL
« Reply #20 on: 04 August, 2017, 02:38:26 pm »
All the best for whichever tests are lined up.

Morat

  • I tried to HTFU but something went ping :(
Re: chronotrope incompetence and not finishing LEL
« Reply #21 on: 08 August, 2017, 09:14:44 pm »
Food for thought!
The input of an exercise physiologist would be helpful.
I also ponder whether military and expedition type physicians might have thoughts or experience.

I also don't know how much data and experience the pundits have with people of our age group.

Military rations have a quite amazing calorie count for their relatively low volume. IIRC it's about 4000 calories a day on the standard ones and even higher for Arctic rations. Dehydration and Heat Exhaustion are a greater risk to troops than lack of rations partly because water is so damn heavy.
Everyone's favourite windbreak

Chris S

Re: chronotrope incompetence and not finishing LEL
« Reply #22 on: 08 August, 2017, 09:52:37 pm »
Multiple nights of poor sleep would bugger me up, for sure.

Ever had an RQ profile done? Might shed light on how well you burn fat at higher work rates.

mattc

  • n.b. have grown beard since photo taken
    • Didcot Audaxes
Re: chronotrope incompetence and not finishing LEL
« Reply #23 on: 08 August, 2017, 10:53:29 pm »
Multiple nights of poor sleep would bugger me up, for sure.

Ever had an RQ profile done? Might shed light on how well you burn fat at higher work rates.
Exactly what I thought on reading this (I have no idea what RQ is!!! ):

"
I started at 13:45 but had not slept well for the last 3 nights due to work pressures and excitement/worry.  This relative sleep deprivation may be relevant.

My plan had always been once I knew my start time  to ride through the night to the Humber Bridge and then stay at the Premier Inn (100m off route).  ...

3 hours sleep and a rather poor breakfast I set off again.

"

That is very little sleep for the amount of exercise involved.
Has never ridden RAAM
---------
No.11  Because of the great host of those who dislike the least appearance of "swank " when they travel the roads and lanes. - From Kuklos' 39 Articles

Re: chronotrope incompetence and not finishing LEL
« Reply #24 on: 10 August, 2017, 02:10:38 pm »
I saw the cardiologist today.  turns out I did have an ECG last year when I broke my collarbone and yes there are changes between then and now!

Even today 1 week after DNF, there are changes on the ECG which suggest that there is either evidence of exercise or a small inferior infarct with possible Wolf Parkinson White like anomaly.

So I get to have an exercise tolerance test and an echocardiogram and be seen again. 

I am also arranging to go and see the premier British sports exercise cardiologist in Liverpool once I have had all the tests.

I continue to believe I am fit and well and that this is a response to exercise.

What would be really interesting would be to see if we could get ECGs on 50 or so Audaxers over the age of 55 and look at trends.