11 Physical Health Numbers That Affect Your Mental Health

Most people think of mental health as something that’s “all in your mind.” But in reality, physical health plays a crucial role in how you feel emotionally and mentally. Your body and brain are closely connected, and physical health factors can significantly impact your mood, cognition, and overall mental well-being.

One effective way to support your mental health is by understanding specific physical health metrics. Knowing these 11 important health numbers provides insights into areas where even small changes can make a big difference in how you think, feel, and function.

Here’s a guide to these 11 health numbers and why they’re worth discussing with your doctor.

1. Blood Pressure

Over 60% of adults in the U.S. have high or borderline-high blood pressure, according to the CDC. Important to note: Blood pressure readings are given in two numbers: systolic (top) and diastolic (bottom), with a healthy range generally being below 120/80 mm Hg.

Knowing if your blood pressure is high is important, because elevated levels can lead to reduced blood flow in the brain. Inadequate cerebral blood flow can reduce oxygen levels, depriving your brain cells of essential nutrients. Over time, this can lead to cognitive decline and increases the risk of developing dementia.

Improve your numbers: Psychiatrist and brain health expert Dr. Daniel Amen suggests maintaining healthy blood pressure to support your body with nutritious food and mental health with brain healthy habits.

2. Complete Blood Count (CBC)

A complete blood count (CBC) provides a wealth of information about your body’s production of red and white blood cells and can highlight potential issues like anemia. Research shows that iron deficiency anemia, often due to low iron levels, can lead to mental health symptoms, such as low mood and anxiety.

When iron levels are low, oxygen delivery to the brain may be compromised, cognitive function is reduced, and mood changes become more frequent.

Improve your numbers: Understanding brain health can help you learn which CBC numbers promote consistent focus, mental clarity, and energy.

3. C-Reactive Protein (CRP)

C-reactive protein (CRP) is a clinical marker of chronic inflammation linked to various mental health conditions, including major depressive disorder, post-traumatic stress disorder (PTSD), and Alzheimer’s disease. Tracking CRP levels provides insight into underlying inflammation that could be silently impacting your mental health.

Chronic inflammation is detrimental to your body and brain, especially your cognitive function. This can accelerate brain aging, impair memory, and elevate stress levels.

Improve your numbers: Aiming to reduce inflammation through lifestyle changes—like anti-inflammatory foods, regular exercise, and stress management—can have lasting benefits for your physical and mental health.

4. Hemoglobin A1C

Your A1C level reflects your average blood sugar over the past three months and is a crucial number to monitor. Research suggests that elevated A1C levels, commonly associated with prediabetes and diabetes, impair brain function and can put you at an increased risk of mental health problems like depression.

High blood sugar levels can damage blood vessels and change your brain health over time, increasing the risk of developing conditions like dementia.

Improve your numbers: Dr. Amen says that balancing your blood sugar through mindful eating habits is essential in maintaining brain health and emotional well-being.

5. Ferritin

Ferritin is a blood protein that stores iron, and low ferritin levels can lead to fatigue, attention problems, low mood, anxiousness, and sleep disturbances. Iron plays a significant role in how your body makes critical neurotransmitters—serotonin, dopamine and norepinephrine—that determine everything from concentration to energy to emotional balance.

Research shows a connection between low iron levels and mental health disorders like depression, anxiety, ADHD, and schizophrenia.

Iron is essential for oxygen transport in the blood, supporting brain function and cognitive performance. A ferritin test helps identify low iron levels that may be impacting mental clarity and emotional stability.

Improve your numbers: You can boost your ferritin levels through a balanced iron-rich diet and supplementation that enhances your energy and boosts cerebral blood flow.

6. Omega-3 Index

The Omega-3 Index test measures the amount of EPA and DHA in your red blood cells with optimal levels starting at 8% or higher. A wealth of scientific evidence shows that omega-3 fatty acids are vital for overall health and critical brain functions including mental health.

A low Omega-3 index is associated with increased risk of depression, cognitive decline, and accelerated brain aging.

Diets rich in omega-3 fatty acids—like those from fish, flaxseeds, and walnuts—can boost brain cell function, reduce inflammation, and support mood stability.

Improve your numbers: Dr. Amen recommends tracking and improving your Omega-3 index is a proactive way to support your mental health.

7. Hormone Levels

Key hormones like thyroid, testosterone, estrogen, DHEA-S, cortisol (the stress hormone), and insulin all play vital roles in brain function. When these levels are out of balance, it can have a ripple effect on mood, energy, and cognitive health.

For instance, high cortisol levels can impair memory, while imbalanced thyroid levels can lead to mood disorders and adrenal fatigue.

Improve your numbers: Test your hormone levels to pinpoint imbalances and make lifestyle or dietary adjustments that promote a healthier brain and emotions.

8. Body Mass Index (BMI)

Your BMI, calculated from your height and weight, should be used as a tool to guide your steps towards a better life, not the end all be all of overall health. The ideal BMI range is between 18.5 and 24.9.

While it doesn’t tell the full story, your BMI can offer a quick snapshot to set a healthier foundation whether you’re underweight, at a healthy weight, or overweight.

Excess body fat is linked to a higher risk of mental health issues such as depression, according to a 2024 study in Plos One. In addition, excess weight is associated with increased inflammation, which can negatively impact brain function.

Improve your numbers: Talk to your health care provider about how to achieve a more balanced BMI for your body type to promote better mental health.

9. Waist-to-Height Ratio (WHtR)

Waist-to-height ratio (WHtR) is a simple but effective measure to understand your health risk related to abdominal fat. Ideally, your WHtR should be 0.5 or lower. Quick tip: if your waist circumference is half your height, you’re in a healthier range.

Abdominal fat, in particular, produces pro-inflammatory substances that contribute to brain fog and impaired mental function. Findings from a 2023 study show that a high WHtR is linked to neurobehavioral issues in adolescent development, reduced brain volume, memory loss, and emotional regulation.

Improve your numbers: Understanding this number can guide you in making dietary and lifestyle changes that may help positively change your brain health.

10. Sleep Duration

Most people understand their need for food, water, and shelter are critical to survival. However, too many of us don’t consider how sleep is one of the most important elements in your overall health.

The quality and duration of sleep significantly influence brain function, with less than seven hours a night linked to an increased risk of cognitive issues. Sleep deprivation impairs memory, focus, and mood regulation. Over time, it may contribute to conditions like dementia.

Improve your numbers: Dr. Shane Creado, a psychiatrist and sleep specialist at Amen Clinics, says you can prioritize sleep hygiene through simple habits to achieve better, more restorative sleep like:

• Setting a consistent sleep schedule
• Reducing screen time before bed
• Creating a calm and cozy pre-sleep routine
• Follow your natural circadian rhythm to avoid late night sleeping

11. Daily Servings of Fruits and Vegetables

Eating at least eight servings of fruits and vegetables daily is associated with increased happiness and improved brain health. Nutrient-rich produce provides antioxidants and vitamins that support brain health and, according to research, reduce the risk of mental health disorders.

Eating a plant-rich diet promotes cognitive health by reducing oxidative stress and inflammation in the brain.

Improve your numbers: Making fruits and vegetables a dietary staple is a simple way to invest daily in your physical and mental health.

11 Ways to Boost Your Mental Health

Each of these 11 important health numbers offers valuable information about your body and brain’s current state. By improving your numbers, you’re prioritizing a healthier body and mind. With the right knowledge and brain health education, you have the power to “change your brain, change your life.”

Read Amen University’s Change Your Brain Every Day course to learn more about how these metrics directly impact mental well-being and what you can do to improve them.