Can stress disrupt hormone function?
When was the last time you were stressed? This morning, last Friday in that meeting, or perhaps right now? Stress is such an ubiquitous part of modern life that it may feel more apt to ask instead: when was the last time you weren’t stressed?
Stress is so common that it’s often overlooked as a major driving force behind changes in hormone levels, bodily functions, and our emotional health. In 2018, the Mental Health Foundation found that 81% of women surveyed in the UK had felt overwhelmed or unable to cope in the year prior.
Hormones work together to influence the changes that happen throughout a monthly menstrual cycle, as well regulating the body’s responses to perceived danger. These functions can all be challenged by acute or chronic stress.
“Because of modern life and technology, many of us are more likely to be exposed to prolonged states of stress. But there isn’t enough research into the long term effects of stress”
Isabella Goldie, director of the Mental Health Foundation, highlights stress as an affective factor in the case of depression and anxiety, while also pointing out that it can impact sleep patterns, our digestive system, affect our immune response, and possibly contribute to the later development of heart disease.
“Millions of us around the UK are experiencing high levels of stress and it is damaging our health. Stress is one of the great public health challenges of our time, but it still isn’t being taken as seriously as physical health concerns,” she says. “We need to change at a societal level. This includes ensuring that employers treat stress and mental health problems as seriously as physical safety.”
While healthcare professionals recognise that there’s a link between stress and the onset of physical and mental symptoms, there’s no concrete evidence that establishes exactly how stress plays a part within, or how significant its impact is, for our short and long-term health.
Which hormones are impacted by stress?
The hormones adrenaline and cortisol are directly affected by stressful situations. Adrenaline is quickly triggered when the body is put under stress, regulating our fight-or-flight response. It’s produced by the medulla — the inner section of an organ or tissue – inside the adrenal glands, as well as by the neurons in the central nervous system.
Cortisol is a steroid hormone that helps to shape our diurnal rhythm, also known as our ‘sleep and wake’ cycles. It tends to be higher in the morning and fall throughout the day, though physical or mental stressors can cause it to spike temporarily, including strenuous exercise.
Endocrinologist Dr Nida Chammas says that while adrenaline and cortisol are the first hormones to be impacted by stress, levels of luteinising hormone (LH) and follicle-stimulating hormone (FSH) can also be thrown out of balance by stress, which can result in fewer periods, missed periods, and fertility issues.
“If a person is under a lot of stress, it can suppress both LH and FSH,” she says. “This can result in losing your period and relates to both mental and physical stress, like a bereavement or intense strenuous physical activity for those who compete professionally.”
Could this affect my cycle?
Both FSH and LH drive the ovulation process: FSH stimulates the ovarian follicle, helping an egg to start growing, while LH is responsible for the release of that egg from the ovary once it’s developed enough.
Dr Chammas also points out that levels of the hormone prolactin can be elevated by stress, which can cause the breasts to start lactating and can also disrupt the menstrual cycle. However, a prolactin imbalance can often be asymptomatic until the levels of this hormone become high enough to inhibit LH and FSH.
“While elevated levels of prolactin can cause both secretions from the breasts and missed periods, it often doesn’t produce any symptoms,” she says. “You could have high levels of prolactin and never experience missed periods, tender breasts, or secretions from the nipples at all.”
Even those with high-pressure lifestyles are more likely to experience frequent spikes and drops in cortisol and adrenaline rather than a constant high level of these hormones
One study found that the contraceptive pill and hormone variations during a woman’s cycle may impact stress levels.1 This could point towards higher levels of certain hormones being linked to more sensitive stress responses.
“It shows [the study] male stress hormone levels are greater than or equal to that of women in the second half of their cycle,” says Dr Pastides. “Women in the second half of their cycle have higher stress levels than women in the first half of the cycle.
“And women on the pill have the lowest measured stress hormone levels.”
Though Dr Pastides also points out that how these changes in stress levels affect fight-or-flight responses is unclear. She also highlights that other studies have contradicted this study’s findings, making its results unreliable.
Stress, hormones, and glucose
Cortisol and glucose levels are interlinked, which means that during stressful stretches of time, higher levels of cortisol can cause higher glucose levels. Dr Chammas explains that this is why healthcare professionals often see high glucose levels in patients with infections, as the body is under stress trying to fight off bacteria, fungus, or a virus.
Though high cortisol levels caused by stress can cause glucose levels to rise, Dr Chammas says that the long-term effects of this on the body are unclear because most stressful situations are temporary. Even those with high-pressure lifestyles are more likely to experience frequent spikes and drops in cortisol and adrenaline rather than a constant high level of these hormones.
“High glucose levels caused by stress are very unlikely to cause a condition like diabetes,” she says. “That just doesn’t happen. It’s important to make that distinction. Adrenaline can have a similar effect on glucose levels because cortisol and adrenaline work together.”
A prolonged or intensely stressful situation can result in the body mimicking hyperthyroidism symptoms like excessive sweating, a racing heartbeat, itching, heat intolerance, muscle weakness, and even a fine tremor
But, says, Dr Claudia Pastides, stress could be a contributing factor to diabetes, particularly in children.
“Stress is a significant factor in the development of Type 1 diabetes in children, mainly because stress can impact development because it limits the growth hormone,” she explains. “The relationship between stress and diabetes is complex. Stress does not directly cause diabetes, especially in adults, but it could be a contributing factor.”
A prolonged or intensely stressful situation can result in the body mimicking hyperthyroidism symptoms like excessive sweating, a racing heartbeat, itching, heat intolerance, muscle weakness, and even a fine tremor. This hyperthyroid-like state can also cause digestive issues, such as diarrhea, and extreme weight loss can happen seemingly out of nowhere. The opposite can also happen, weight gain — particularly around the midsection — can be caused by the rise in glucose levels, causing our body to convert more carbohydrates into fat.
Dr Chammas adds that, in general, irritability is a common symptom of hormone imbalance caused by stress, and says that in chronic cases, stomach ulcers can form.
Why isn’t there more research on this?
Dr Pastides says that research on the link between hormones and stress is lacking because people can’t ethically be subjected to stress for a prolonged period of time as a means of study.
“While studies on animals have suggested a correlation between stress, hormones and bodily functions. The same studies can’t be replicated on women.” she says. “We know there is definitely a link between stress and things like thyroid function and insulin, but why and how this happens is less clear.”
She adds, “Because of modern life and technology, many of us are more likely to be exposed to prolonged states of stress. But there isn’t enough research into the long term effects of stress, which means we don’t always know who’s more susceptible or if bodily function will be impaired.”
This has resulted in the research that is available often being inconclusive. Some studies have picked up correlations between stress and certain chronic conditions, like irritable bowel syndrome, though how stress exacerbates or even causes these conditions is still unclear. A research report found that early life stress in infant rats resulted in a disrupted ‘brain to gut axis’ which points towards a link between gut conditions and stress.2
This is why stress is currently viewed as a contributing factor to many physical and mental health conditions, rather than a main cause or driving factor.
1. Kirschbaum, C., Kudielka, B., Gaab, J., Schommer, N., & Hellhammer, D. (1999). Impact of Gender, Menstrual Cycle Phase, and Oral Contraceptives on the Activity of the Hypothalamus-Pituitary-Adrenal Axis. Psychosomatic Medicine, 61/2: 154-162.
2. O’Mahony, S., Marchesi, J., Scully, P., Codling, C., Ceolho, A., Quigley, E., & Cryan, J. et al. (2009). Early Life Stress Alters Behavior, Immunity, and Microbiota in Rats: Implications for Irritable Bowel Syndrome and Psychiatric Illnesses. Biological Psychiatry, 65/3: 263-267.