A growing body of research makes it clear that mental health and physical health are deeply connected, with studies showing that an improvement or decline in one can lead to an improvement or decline in the other. But how exactly does one influence the other? What exactly is happening in the body to allow changes in one to change the other?
The Relationship Between Mental Health and Physical Health
To understand why mental health and physical health are so closely linked, it’s important to remember that the distinction between the two is less important than we may assume. Our thoughts, moods, and mental state may feel abstract or separate from the physical, but they are all happening as part of our brain activity.
A good example of how interconnected your brain and body are is the set of mental and physical changes that happen during the menstrual cycle. More and more research is showing that hormonal shifts throughout the menstrual cycle impact far more than just the reproductive system.
How Does Physical Health Affect Mental Health?
One of the most well-established impacts on mental health is on changes in dopamine, a “happiness hormone” associated with motivation and reward. Estrogen downregulates dopamine transmission. So when estrogen levels spike—which happens once right before ovulation and again right before your period—your dopamine levels dip. For people with ADHD, that can make symptoms even worse. But for people with bipolar disorder or other conditions involving psychosis, that can make psychosis symptoms better.
Meanwhile, when progesterone levels start to increase in the second half of your cycle, it increases levels of allopregnanolone, a neurosteroid that can act as an antidepressant, anti-anxiety, and pain-reliever in high doses but, paradoxically, causes increased anxiety, irritability, and other negative mood symptoms at low levels. This paradoxical effect is most noticeable when progesterone levels drop off sharply in the final days before your period starts and is a contributing factor to the mood changes associated with PMS.
Reproductive hormones aren’t the only ones to be linked to mental health. Metabolic hormones—insulin, cortisol, leptin, and so on—have been found to impact a wide range of mental illnesses, from ADHD to schizophrenia to eating disorders.
Research shows that interaction is a two-way street. Metabolic problems like diabetes, hypertension or even just prolonged periods of poor nutrition can cause stress-induced changes to the brain that lead to mood and neurodevelopmental disorders. Likewise, mood and neurodevelopmental disorders can cause stress that triggers metabolic changes that, over time, can develop into those same metabolic diseases.
How Does Mental Health Affect Physical Health?
A number of studies have found that mental illness may accelerate biological aging, manifesting as increased rates of cardiovascular disease, age-related diseases, and up to 10-20 years shorter life expectancy.
It’s important to clarify that there is a lot of nuance to those findings, so being diagnosed with, say, depression does not mean a shorter life expectancy is guaranteed. These studies are largely based on epigenetic clocks, an algorithm for predicting biological age based on a process called DNA methylation.
But there’s a lot more involved in aging than just DNA methylation. So it’s more useful to think of your epigenetic clock as a risk factor or predictor, similar to how a person with a genetic predisposition for breast cancer is at higher risk but not guaranteed to get cancer.
What the research shows is that psychological stress that comes with many mental illnesses may be linked to premature aging in a few different ways:
*Stress can lead to unhealthy behaviors like poor diet, lack of exercise, and substance use that are bad for physical health.
*Stress can disrupt sleep, which can harm physical health over time.
*Stress can cause chronically elevated levels of cortisol, which can disrupt just about every bodily function, including the digestive system, immune system, cardiovascular system, and even reproductive system.
For people with mental illness, this can put them at risk for a range of chronic conditions, including:
High blood pressure
Tips for Maintaining Mental and Physical Health
There is a silver lining to all the research on the interactions between mental and physical health: it shows that the body and brain are both extremely responsive to change.
That adaptability is partly what caused the snowball effect of any mental and physical health symptoms you’re currently facing. But it’s that same adaptability that will allow anything you do to take care of yourself to have just as much power to trigger a snowball effect of positive changes in your body. Here are a few places you might start.
Make Regular Exercise a Lifelong Habit
The physical and mental health benefits of regular exercise are hard to overstate. It improves muscle mass and function, improves metabolic function, reduces inflammation, strengthens the immune system, improves cardiovascular and respiratory health, and even contributes to better gut microbiome diversity.
All of those physical health benefits will, in turn, improve mental health because they’re interconnected. But exercise also has direct benefits for the brain as well. Those benefits include improved cognitive function; improved executive function, including working memory and impulse control; reduced depression and anxiety symptoms; and reduced stress.
Many of these benefits are cumulative, meaning you’ll have to stick with an exercise routine for a few weeks before you notice a difference. But exercise may also have some useful immediate benefits, including an elevated mood for several hours after exercise, improved energy levels, and mild pain relief.
For optimal short and long-term benefits, follow these tips:
*Don’t overdo it. Intense training can end up counteracting the physical and mental benefits of exercise because they cause stress and put you at risk of injuries.
*Aim for 150-300 minutes of moderate aerobic physical activity per week, including some muscle-strengthening activities at least two days per week.10
*Pick activities you actually enjoy. Exercise doesn’t have to be about peak performance or maximizing each workout. It just has to be something that gets your body moving and maybe challenges you a bit when you have the energy to challenge yourself. Hike, swim, dance, play with your dog, go for a walk, whatever gets you moving without dreading the idea of exercising. If you don’t know what you enjoy, try something different every week until you find it.
*Start with ridiculously small goals. To avoid quitting before exercising becomes a habit, start by setting daily goals that seem so easy it would be ridiculous not to do them. Each week, set the goal a little higher.
Eat a Healthy, Balanced Diet
Diet is one of the most important risk factors of illness,11 but it can also be one of the most confusing lifestyle changes to make. There’s so much conflicting information out there about what you should and shouldn’t eat. Plus, a lot of diet plans ask you to meticulously track things like fiber, protein, and micronutrients. It’s overwhelming.
Instead of trying to follow any optimized diet plan or figure out which trending superfood you should be eating, just follow a few basic principles of good nutrition and then don’t stress about it:
*Drink more water. Between three to four liters per day is the general recommendation. Don’t worry about alkalinity or electrolytes. Any safe drinking water will hydrate you.
*Eat more fruits and veggies. The recommended five servings work out to about 1 ½ to 2 pounds per day. Any fresh produce will be good for you, so don’t overthink it. With canned and frozen options, just make sure there isn’t a lot of added sugar or salt.
*Be mindful of processed foods. Even minimally processed and ready-made foods, like bread or soup, can contain a surprising amount of salt and sugar. If you do have these ready-made options, check the label to try to find low-sodium, low-sugar alternatives.
If your current habits aren’t ideal, don’t worry about getting them perfect right from the start. Pick one change to focus on at a time so that you can turn these into lifelong habits.
Make Time for Doing Nothing
A lot of health advice, including the tips above, center on things you need to do or change. But it’s also important to remember that stress is a major factor in the harmful interactions between mental and physical health. So part of your healing process should include finding time to not worry about whether you’re eating the right thing, exercising enough, or being productive enough.
Just take a few minutes each day to sit down with no TV, no phone, no other distractions and just be. Notice where you are and what you’re feeling right now. That’s it. Don’t think about what you have to do after this or what you should be feeling or doing right now. Just be for a few minutes, maybe even for 40-45 minutes if you have the time.
This is often referred to as mindfulness, but don’t let the label pressure you into putting criteria around what you should be doing or how to optimize this time. The goal is to just check in with yourself and take a break from the noise of life for a bit. You can try a more defined mindfulness exercise once you’ve made a habit of carving out this time for yourself if you want to.
By Rachael Green
Photo by Cottonbro Studio