Hi,
I’ve ordered thyroid tests with Medichecks. Does working night shift affect the results? Ideally I’d get someone at work (hospital) to take them in the morning before heading home. Will this make any difference? Should I wait a few weeks until I’m working days again?
An awfully big assumption - and I would NOT go along with it. There has been very little work on how night-shifts affect thyroid (TSH, FT4 and FT3). Abstract of one of the few below:
Presse Med. 1999 Feb 6;28(5):252-8.
[Biologic rhythms: their changes in night-shift workers].
[Article in French]
Weibel L1, Follénius M, Brandenberger G.
Author information
1 Laboratoire des Régulations Physiologiques et des Rythmes Biologiques chez l'Homme, Institut de Physiologie, Faculté de Médecine, Strasbourg.
Abstract
ENVIRONMENTAL STRESS:
Environmental cycles, such as the light-dark cycle, provide information used by the biological clock in the hypothalamus to synchronize the biological systems and maintain the organism's internal cohesion. In persons whose work schedules include night hours (approximately 20% of the working population in France) the sleep-wake cycles are not in phase with these environmental cycles.
BIOLOGICAL RHYTHMS:
What effect does the conflicting information perceived by night-shift workers have on their biological rhythms? Indices of the processes going on in the cerebral clock, these biological rhythms are the only tool available in man to determine possible dysfunction of the clock. Several studies have identified these rhythms in night-shift workers but results have been contradictory.
PARTIAL ADAPTATION:
Recently we made repeated measurements every 10 min over a 24 hour period in night-shift workers to determine the precise melatonin, cortisol, and thyrotropin (TSH) patterns, which reflect the endogenous clock, and prolactin (PRL) and growth hormone (GH) patterns which are influenced by sleep but also have a circadian component. This study demonstrated that there is some, but partial, adaptation of the biological rhythms in these persons. The shift in the melatonin pattern is quite variable from one individual to another. Night work causes a distortion in the cortisol and TSH rhythms. This partial adaptation is also seen in the GH and PRL curves, mainly related to sleep, but whose endogenous component previously described in other experimental situations is found in night workers with a distribution incompletely adapted to the secretory episodes.
RESEARCH PERSPECTIVES:
Both daytime sleep and night-time work are associated with perturbed endocrine functions which could explain certain health problems and sleep disorders observed (or avowed) after several years of night-shift work. These problems require further research into factors susceptible of resynchronizing the biological clock.
PMID: 10076605
If the whole paper were available - and in English - it might help. As it is, I don't know.
It might be best to do as the original poster suggested and waiting until back on days for a while? But I have no idea how long it takes return to non-night shift patterns.
I have no doubt whatsoever that shift work can play havoc with body rhythms. I just don't think the havoc amounts to a nice simple (and thus understandable) inversion.
I work rolling shifts, 2 earlies, 2 lates, 2 nights and four off. I am naturally a night owl to boot. Because of the constant change, our circadian rhythms are shot and I could not get a good answer to the question either. The best we could come up with was be consistent. I always test at 0900 on my third rest day as I never have a long enough period to fully reset so consistent is the best I can do. I am about to go on to 2x 7-7 days, 2x 7-7 nights and 4 off which will make things even worse and Im still trying to work out how to fit in a cortisol saliva test, think it will have to wait til I am on leave!!
If you do a week of each shift and get up at the same time eg on days and rest days you could test on your last rest day before the new pattern starts as that is when your rhythm is as stable as its probably going to get. By testing at the same time and on the same ‘day’ within your pattern you should have comparable results so you just need to work out the longest stretch that fits in with your prefered sleep pattern.
Been doing that one for 17 years its actually quite a nice pattern believe it or not as if there is a shift you hate (earlies!!) there are only 2 of them and you can get a good ‘lie in’ at each switch I am lucky I can sleep pretty much any place and any time but fitting in consistent tests does take planning.
Starting 4 on 4 off 12 hour shifts next week 2x 7-7 days and 2x 7-7 nights not looking forward to it at all, but that was the price of keeping jobs. I hate earlies but it would have been better to do 4 days or 4 nights so you could get into any kind of rhythm. 😭
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