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Long Working Hours Increase the Risk of Hypothyroidism

Working long hours can wreak havoc on your health – especially your thyroid. What can you do?
Long Working Hours Increase the Risk of Hypothyroidism
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“Can you stay late?” “I need that report by tomorrow morning at the latest!” “Jane is out with Covid. Can you cover her shift?” “We need you to increase productivity!” Who hasn’t heard something like this from an employer at one time or another? Lately, it seems that the combination of economic downturns and the continuing pandemic has resulted in much longer working hours for many people.

But how much work is too much? Does working more than 9 to 5 wreak havoc on your health? And what does it mean for your thyroid? Why are long working hours a risk factor for an underactive thyroid gland? Ahead, a look at the link between working long hours and hypothyroidism.

Working long hours doubles the rate of hypothyroidism

A large study published in November of 2022 reported that long working hours directly correlate with the incidence of hypothyroidism. Specifically, the systemic review found that the rate of hypothyroidism is noticeably higher in people who work 53 to 60 hours a week and significantly higher in people who work more than 60 hours a week. The relationship is particularly strong in people over the age of 36.

The 2022 study confirms the findings of a 2020 study of more than 45,000 people in South Korea that evaluated the risk of hypothyroidism in people with different working hours. That study – presented at the Endocrine Society meeting that year and published in the journal Thyroid – found that those who worked 53 to 83 hours a week had double the rate of hypothyroidism compared to those who worked 36 to 42 hours. According to the study, every additional ten hours worked per week increased the risk of hypothyroidism by 46%, compared to people who worked ten fewer hours per week.

According to one of the study’s authors, Dr. Young Ki Lee:

“If a causal relationship is established, it can be the basis for recommending a reduction in working hours to improve thyroid function among overworked individuals with hypothyroidism. Additionally, screening for hypothyroidism could be easily integrated into workers’ health screening programs using simple laboratory tests.”

Why does working long hours increase the risk of hypothyroidism?

We already know that long working hours have adverse effects on many aspects of health, including an increased risk of heart disease, metabolic syndrome, diabetes, obesity, and mental health problems like depression.

According to the World Health Organization, long working hours – which they define as 55 or more hours per week – increase the number of strokes by 35% and increase the risk of dying from heart disease by 17% compared to working 35 to 40 hours per week.

According to Dr. Maria Neira, Director of the Department of Environment, Climate Change and Health at the World Health Organization, “Working 55 hours or more per week is a serious health hazard.”

Researchers, however, don’t have a definitive reason to explain how working long hours specifically relate to the risk of hypothyroidism, and more research is needed. But one possible theory might partly explain the link. People who work long hours tend to get less sleep. Short sleeping – sleeping less than 7 hours per night – is associated with immune dysregulation. An immune system that doesn’t function properly increases the risk of autoimmune thyroid conditions like Hashimoto’s disease, the primary cause of hypothyroidism in the U.S.

Lack of sleep also interrupts the process of thyroid hormone conversion and can result in reduced thyroid hormone levels, which may contribute to hypothyroidism.

Finally, short sleeping contributes to increased levels of stress and elevated cortisol levels, contributing to adrenal insufficiency, which also increases the risk of hypothyroidism.

What can you do?

If you work long hours and develop any common symptoms of hypothyroidism – such as fatigue, weight gain or difficulty losing weight, brain fog, mood changes, or other signs – it’s crucial to have a complete thyroid test panel done to test the function of your thyroid gland and consult a healthcare provider for evaluation.

If you regularly work long hours, consider scheduling complete thyroid screening every six months – at a minimum – as a routine part of your healthcare management.

If you are hypothyroid, it’s also vital to get at least 7 hours per night of quality sleep. Sleep helps support healthy immune, adrenal, and endocrine function and helps modulate the stress response. Getting sufficient quality sleep also helps relieve hypothyroidism symptoms such as continuing fatigue and brain fog. Paloma’s free Simple Guide for Healthy Sleep can help get you started making sleep a top priority.

Finally, there’s no doubt that working long hours is not good for your health in general, much less your thyroid. That means it’s essential to consider ways you may be able to achieve a better work-life balance and reduce working hours to more manageable levels.

A note from Paloma

The Paloma Complete Thyroid Blood Test kit makes regular thyroid testing easy and affordable. The Paloma home thyroid test kit includes everything you need to measure your levels of thyroid hormone conveniently at home with a painless finger prick. The kit evaluates your thyroid gland, measuring thyroid hormone levels, including Thyroid Stimulating Hormone (TSH), Free T3, Free T4, and Thyroid Peroxidase antibody (TPO) levels, with the option to add on reverse T3 and vitamin D levels. After you mail your kit to our lab, your thyroid test results are released to your secure online dashboard within days, similar to the wait time for in-person lab results—without the inconvenience.

For comprehensive diagnosis, treatment, and management of hypothyroidism, many patients across the U.S. choose to work with Paloma’s dedicated team of top thyroid doctors. Paloma’s thyroid-savvy healthcare providers can work with you to evaluate your test results, find the best and most effective thyroid hormone replacement medication, and help resolve continuing symptoms.

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Lee Y, Lee W, Kim HR. Long working hours and risk of hypothyroidism in healthy workers: A cohort study. Epidemiol Health. 2022 Nov 8:e2022104. doi: 10.4178/epih.e2022104. Epub ahead of print. PMID: 36397244.

Lee YK, Lee DE, Hwangbo Y, Lee YJ, Kim HC, Lee EK. Long Work Hours Are Associated with Hypothyroidism: A Cross-Sectional Study with Population-Representative Data. Thyroid: Official Journal of the American Thyroid Association. 2020;30(10):1432-1439. doi:10.1089/thy.2019.0709

Working too many hours may lead to an underactive thyroid. Published March 31, 2020. Accessed November 27, 2022.

WHO. Long working hours increasing deaths from heart disease and stroke: WHO, ILO. Published May 17, 2021.

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Mary Shomon

Patient Advocate

Mary Shomon is an internationally-recognized writer, award-winning patient advocate, health coach, and activist, and the New York Times bestselling author of 15 books on health and wellness, including the Thyroid Diet Revolution and Living Well With Hypothyroidism. On social media, Mary empowers and informs a community of more than a quarter million patients who have thyroid and hormonal health challenges.

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