Thyroid Stimulating Hormone levels (TSH) and audax riding

[cyclinggeezer]

Does any one have knowledge or experience from routine blood tests that shows that audax riding can stimulate the Thyroid Stimulating Hormone (TSH) from their pituitary gland to produce higher than normal levels?

Just had a couple of tests that showed I was just over the higher normal range. (borderline just) Previous tests have shown it fluctuates back again within normal limits at other times. The effect of more TSH in the bloodstream is it reduces T3/T4 from the thyroid gland.

Having done a bit of research now I find this is quite common in folk doing endurance/high intensity training. GP seems ok about it and wants a re test in six months. Whats normal for audax riding as it must change the physiology?


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[hellymedic]

High TSH levels suggest your thyroid is possibly underperforming a tad.

Extreme exertion is not a normal testing scenario and, like your GP, I would suggest a repeat test after a suitable interval, at 'rest'.

I might request an earlier retest if there were symptoms of an underactive thyroid, like general slowing, feeling unusually cold, weight gain, voice deepening or 'bad hair'.

[IJL]

Just had a couple of tests that showed I was just over the higher normal range. (borderline just) Previous tests have shown it fluctuates back again within normal limits at other times. The effect of more TSH in the bloodstream is it reduces T3/T4 from the thyroid gland

Its the other way around TSH stimulates the thyroid to produce T3 and T4.  Its a negative feedback loop, as thyroid hormone levels fall TSH is produced to maintain the production of thyroid hormone.  If the thyroid is beginning to fail then ever more TSH is produced in an effort to maintain the level of thyroid hormone.   Most of the time thyroid function is monitored by testing for TSH rather than the actual thyroid hormones.

If you are just borderline it may mean nothing, a line has been  drawn in terms of defining normal and a huge number of people lie just outside the line (this applies to almost all tests).

If the TSH  continues to rise over time then you are likely becoming hypothyroid, a useful test is for thyroid antibodies as its often an autoimmune problem.

Unfortunately the best diagnostic plan in cases of slightly altered TSH is often "watch and wait".  The thyroid hormones have such a long half life that 3 -6 monthly tests will be able to diagnose a failing thyroid before you develop symptoms, equally they may show that  you're one of the many people who lie outside of whatever the lab has decided is "normal" 

[HK]

I have now have a significant history of increasing TSH and dwindling T4 having previously had seriously elevated T4.  I have an autoimmune condition which probably accounts for current TSH / T4 relationship. My autoimmune disease has been ongoing for 25 years this year.  I have cycled almost daily, (including racing at national level for 6 years) for the whole of this time.  My endocrinologist isn't concerned about my current bloods - increasing TSH and decreasing T4 that is approaching our labs bottom range.  My thyroid is simply doing what it is meant to do. Other than some treatment 25 to 23 years ago, I currently receive no treatment for this.  I am happy with that.

With my autoimmune issue, I have looked for some good research with regard to athletic endeavour and the endocrine / immune system.  I am riding between 18,000 and 19,000 miles a year including an average of 9,000km of brevets for the last 12 years.  I have found very little research let alone good scientific studies covering this topic (I'm a clinical researcher by trade).  I'd be interested on what you have found cyclinggeezer.

From my perspective, the sort of research that you would be looking for would be for endurance cycling that is occurring within the steady state (mainly level 1 with some level 2 thrown in) - not the type of effort you would be using if you were training / racing.  The only good study that I am aware of looking at well being in elite cyclists is a retrospective one of Tour de France riders.  The study found that as a cohort they enjoyed better health than the 'normal man on the street' and for the most part had longer than expected life expectancy - known exceptions being Fignon & Anquetil and a small cohort of EPO users.

My personal take on this is not to obsess about numbers being slightly in our out of range.  My test is how well I am irrespective of lab ranges or any trend that might be seen across the results.  Providing I feel well and can do all the day to day stuff like work plus ride my bike then no action required.

[cyclinggeezer]

thanks all for the very helpful replies. First thing to be said is that I have been feeling well and have increased the miles alot over the last two months without issue. Also absolutely no symptons either. Therefore left scratching my head  with these numbers. Ranges for "normal" vary across the country from what I gather. My reason for asking the question was less to do with worry but more to do with curiosity as to why as a fit and healthy 54 year old seems to have numbers above some arbitrary line for normality.

Bit of Googling produced this paper

http://www.nel.edu/26-2005_6_pdf/NEL260605A14_Ciloglu.pdf

Seem to indicate a link with exercise and raised TSH levels, though could not work out if the levels were raised for a lenghty period after hard exercise.

My other slight concern was GPs for good reason are not well up on cycling related health issues and the aches, pains and stuff that might arise from cycling long distances which could be mis diagnosed.


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[HK]

Glad the replies have answered your questions.

Like a lot of blood tests they are a rough guide not an exact one. Generally results have to be significantly outside of 'normal' for action to be taken - this why you need results plus a trained medic to interpret them not the result alone.  You are quite correct the range differed from hospital to hospital depending on the lab. 

My experience is that the symptoms of thyroid disease can't be mistaken for just simple aches and pains from cycling. They generally become totally debilitating.  The human body is way tougher than you think.  I came 3rd (exceeded gold standard by 1 hour) out of 50 or so women on the Tom Simpson sportif over Mt Ventoux when I shouldn't have been able to get out of a chair because my Graves Diseases was so severe, which I found out subsequently at my first appointment with an endocrinologist.

With regard to the medics been my clued up on cycling. This is very rare even with consultants.  I have yet to find one.

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[HK]

PS - the study shows very small alterations in TSH (within normal limits) etc at the sort of effort you would expand at say riding a 10 mile time trial. The conclusion was that it was that is was a correct hormonal response to the effect of exercise to the cells that the endocrine system regulates.  It takes a race like the tour to have a minor impact which is short lived - but given what we already know about the effect of this type of racing on the body it would be unexpected and the impact would be short lived.

The article is interesting in as much that the scientists have not answered their question particularly well and conclude that things are more complex than they thought. Pretty much the same story as cancer at the cellular level.

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[cyclinggeezer]

Interesting. Thanks for the inspiration of "stay calm and carry on". My question about the peculiarities of audax is how much difference might it make with say 12 hours/200km of a single event or say 200 or 300 miles spread out over a week? or even more say after an LEL? Point taken about it being short lived. 

I have no experience of reading papers so it was a first attempt at finding some evidence. I have asked the GP for all the previous results and was going to compare them against rides to see what if any correlation there was. Probably none. Just very curious.

I intend to just carry on as normal in preparation for the LEL and as you say the human body is way tougher than you think. To me its thinking you are fragile that stops you doing things. Most of the GPs at my practice think its some what unhinged riding for half a day, full day, several days etc and any excuse to push the boundaries is good in my book. Having had previous mis diagnosis on a couple of issues which resulted in me having to do my own research to prove the medics wrong I tend out of habit now/sense of survival not to take the first off the peg answer thats given.


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[LittleWheelsandBig]

HK has been known to ride three 1200s in seven weeks.

[HK]

Brevets are conducted for the most part in a steady state, sometimes referred to as level 1 & 2 as given the distance riding steady is the way most people can get around them. The only time you are going to stray out of this is say giving it some welly up a hill - this is then balanced out by the descent. But unless the hill is very long it will not equate to what was described in the paper which is a ramp test and having done them when racing these are evil.

Even for the riders that don't accumulate enough time to have a good sleep on a ride such as LEL, the stops at controls for food etc is enough to allow the recovery that you need as you're not pushing your body hard enough to cause it any real recovery issues. The better trained you are the better your body will cope with LEL.

When I was racing tandem with JJ we rode the old Elenith in 13 hours.  I can't remember us getting out of breath.  We'd ride back to back time trials - say a 30 followed by a 50 fast without a problem. The only racing distances that would leave us tired for several days afterwards were 100 mile and 12 hours ridden at a good racing pace eg under 4 hours for 100 miles.

My experience is it's always best to do a bit of research yourself on medical stuff but be careful of getting anxious as there is stuff on the internet that will make you worry without cause.

I'd keep a spreadsheet of your results to see if there is a trend - this is what the thyroid society recommend. However I doubt you will see any correlation between brevets and fluctuation in your bloods.

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[Delph Cyclist]

Brevets are conducted for the most part in a steady state

Yes, I tell my club mates when I get dropped on local club runs that I have trained myself not to go into the red.  There's no use giving it everything on a climb if you know there's another 250km to go.

I find YACF really useful for these health matters specifically associated with our sport, especially when we've got the views and experience from the likes of Hellymedic and HK.