A new downside to working long hours should encourage you to log off

South Korean culture is so well-known for its "inhumanely long work week," as reporters there have put it, that the government in 2018 put a cap on the number of hours that could be worked in a seven-day period.

The government crackdown now has scientific evidence to support the social welfare measure passed by the South Korean Parliament a little more than two years ago.

Working too much in a single week will very likely result in weight gain, fatigue, sensitivity to cold, and hair loss, among other physical symptoms.

A study published Tuesday suggests that these long hours have a cost: workers who spent more than 53 hours on the job had twice the rates of hypothyroidism compared to those who worked between 36 and 42 hours, the study finds.

What may look like dedication, or chasing a passion, can actually manifest itself in long-term harm to the heart or brain, when taken to extremes. A new study adds yet another cost of working long hours all the time to a growing list.

Hypothyroidism is a condition where the thyroid, a gland at the base of the neck, doesn't secrete the adequate amount of thyroid hormone. That deficiency translates to symptoms like weight gain, fatigue, sensitivity to cold, hair loss and a host of others.

The relationship between hypothyroidism and working long hours is small. In the group of workers who labored between 53 and 83 hours each week, 3.5 percent ended up with hypothyroidism (this was confirmed via a blood test records collected from all participants). In the group that worked between 36 and 42 hours each week, 1.4 percent ended up with hypothyroidism.

In the abstract, the team suggests that their work is the "first to show" that thyroid complications have been ties to working long hours.

Even if those numbers are small, they're large in comparison to one another. The group who worked long hours had twice the rate of hypothyroidism compared to those who worked less than 42 hours. And, the team estimates that every ten hours of additional work per week is linked to a 1.4-fold greater chance of having the condition.

This study would have been presented at the Endocrine Society's annual meeting (which has canceled due to the coronavirus pandemic). The abstract was published in a supplemental section of the Journal of the Endocrine Society

This study wasn't designed to investigate why longer work hours seem to impact the thyroid. However, the study's first author Young Ki Lee, a clinical staff specialist at Korea's National Cancer Center tells Inverse that this could come down to a few factors, including obesity or high levels of inactivity. But it could also come down to a persistent feature of overwork: stress.

"Long working hours contribute to psychological stress, and rat models have shown that social, as well as physical chronic stress, reduced thyroid hormone levels," says Lee.

This study adds to a growing body of research suggesting that working long hours can lead to health complications. For instance, a 2019 study of 143, 592 french workers published in the journal Stroke found that long working hours (more than 50 days of working 10 or more hours per day) were linked to 1.29 greater chances of having had a stroke.

All of these studies, including this current one on hypothyroidism, were conducted during a very different time in our working lives (this one pulls data from the Korea National Health and Nutrition Examination Survey between 2013 and 2015). Due to the coronavirus pandemic, many people's work schedules, have been altered or made entirely remote.

Now the question becomes: when we work from home are we still at-risk for work-related health complications?

This study doesn't specifically address whether there are office-specific factors that lead to health complications from long working hours. But it does suggest that working long hours, in general, isn't good for us. And when we work from home, there's some evidence to suggest that we end up working slightly longer hours.

Analysis of VPN data, collected by NordVPN, since March 11 has shown that the average number of hours employees are working has increased by about 3 hours since many Americans started working remotely due to coronavirus. In the US, the average number of working hours has increased from 8 hours per day to 11 hours per day.

We do know that adding "supplemental work" (an extra hour or two on nights or weekends) to our existing work schedules can have harmful effects on health as well. Take this 2014 study that investigated how frequently two populations of European workers (a total of 57,235 people) reported musculoskeletal, cardiovascular or gastrointestinal problems.

People who found themselves doing supplemental work were more likely to report a health problem compared to those who reported that they never did so. Those who reported "often" working during free time were 1.6 times more likely to have a health problem compared to people who protected their free time.

The authors of that study reach a conclusion that might be particularly noteworthy as we adapt to our new work schedules:

"Free time should be free time, otherwise it must be expected that it cannot fulfill functions of recovery and recuperation," they write.

Again this research regarding thyroid complications can't account for the unique work from home environment. The authors of this study tell Inverse that they don't have hard data that can answer that question, but that his research likely applies to people working from home too.

"If we consider 'working from home' as a job type, I think the association between working hours and hypothyroidism would also be present in those who work from home," he says.

"However, care must be taken when interpreting the work hours of people of different work types," he continues."

Although we may not be going into the office anymore, it doesn't mean we should forget about just how important a regular work schedule is. And, what we have to lose when that schedule gets out of control.

As for South Korean workers, since maximum hours they could work per week was brought down to 52 from 68, life has improved, as Korea.net reported in July 2019.

Yoon Ji-su, 38, an office worker for a major corporation whose office is in the Gwanghwamun area, said, "I used to exercise once a week but now I can do it three times thanks to the shorter working hours. I can also have dinner with my family more often."

Abstract:

Background: Studies have highlighted the adverse effects of long working hours on workers’ health; however, the association of long working hours with thyroid function has not been studied. This study aimed to assess long working hours as a risk factor for thyroid dysfunction.

Methods: This cross-sectional study was based on data obtained from the Korea National Health and Nutrition Examination Survey conducted from 2013 to 2015. A total of 2,160 adults who worked 36-83 hours per week were included. Thyroid function was defined based on the population thyroid- stimulating hormone reference ranges, after excluding individuals with positive results for thyroid peroxidase antibody. The association between working hours and thyroid function was confirmed via multinomial logistic regression.

Results: Hypothyroidism was more prevalent among those with longer working hours (3·5% vs. 1·4% for 53-83 and 36-42 working hours per week, respectively). Individuals who worked longer hours had an increased odds for hypothyroidism (odds ratio 1·46, 95% confidence interval 1·12−1·90, per 10 hour increase in working hours per week), after adjustment for age, sex, body mass index, urine iodine concentration, smoking status, shift work, and socioeconomic characteristics such as occupation, income level, and educational attainment. The association between working hours and hypothyroidism was consistent in various subgroups stratified by sex or socioeconomic characteristics.

Conclusions: To our knowledge, this study is the first to show that long working hours are associated with hypothyroidism. Our findings suggest that appropriate monitoring and treatment of hypothyroidism are necessary among individuals who work long hours.