Causes of Fatigue in Women Over 35 Explained
'Why Am I Always Tired?' Common Causes of Fatigue in Women Over 35
Do you wake up feeling exhausted, even after what should have been a good night's sleep? Are you relying on coffee to get through the afternoon or finding it harder to keep up with work, family, and everyday responsibilities?
While occasional tiredness is a normal part of life, persistent fatigue is different. If you're constantly low on energy despite getting enough rest, your body may be signaling that something isn't quite right.
For women over 35, fatigue can have many possible causes. Hormonal changes, poor sleep, thyroid disorders, nutrient deficiencies, chronic stress, and other health conditions can all contribute to feeling tired. In many cases, more than one factor is involved, making it important to look beyond the symptom itself.
This article explores the common causes of fatigue in women over 35, explains when persistent tiredness may warrant further evaluation, and shares practical strategies to help support your energy and overall wellbeing.
What Is Fatigue?
Fatigue is more than simply feeling sleepy after a late night. It is an ongoing sense of physical, mental, or emotional exhaustion that doesn't always improve with rest.
Unlike normal tiredness, persistent fatigue can affect many areas of your daily life, making even routine tasks feel more challenging.
You might notice that you:
Wake up feeling unrefreshed.
Have difficulty concentrating or remembering things.
Feel physically drained throughout the day.
Lose motivation to exercise or stay active.
Depend on caffeine or sugar to maintain your energy.
Feel emotionally overwhelmed by everyday responsibilities.
Fatigue is one of the most common reasons people seek medical advice, but it is a symptom rather than a condition itself. Understanding what's contributing to your low energy is an important step toward finding the right solution.
Is It Normal to Feel Tired All the Time?
Everyone feels tired from time to time. A busy week at work, caring for children or ageing parents, poor sleep, travel, or temporary illness can all leave you feeling exhausted.
However, ongoing fatigue shouldn't be dismissed as a normal part of getting older or simply having a busy lifestyle.
It's worth speaking with a healthcare professional if your tiredness:
Lasts for several weeks or longer.
Doesn't improve despite getting adequate sleep.
Interferes with work, exercise, or daily activities.
Is accompanied by other symptoms, such as unexplained weight changes, low mood, hair loss, digestive issues, or changes in your menstrual cycle.
Recognizing persistent fatigue as a symptom—not a diagnosis—can help you identify and address the underlying factors that may be affecting your health.
What are the Common Causes of Fatigue in Women Over 35?
There is rarely a single explanation for ongoing fatigue. In many cases, several factors interact to affect your energy levels and overall wellbeing.
Below are some of the most common causes.
Poor Sleep Quality
The number of hours you spend in bed isn't the only factor that determines how rested you feel. Sleep quality is just as important.
Frequent waking, an inconsistent sleep schedule, sleep apnoea, restless legs syndrome, or environmental factors such as noise and light can interrupt the deeper stages of sleep that your body needs for physical and mental recovery.
Signs that poor sleep quality may be contributing to fatigue include:
Waking up feeling unrefreshed.
Feeling sleepy during the day.
Difficulty concentrating.
Morning headaches.
Snoring or gasping during sleep.
Needing frequent naps.
If poor sleep becomes a regular pattern, it's worth discussing it with your healthcare provider rather than assuming it's something you simply have to live with.
Hormonal Changes
Hormonal changes are a common reason many women begin to notice a decline in their energy during their late 30s and 40s.
During perimenopause and menopause, fluctuating levels of estrogen and progesterone can influence:
Sleep quality
Mood
Energy production
Body temperature
Mental clarity
Some symptoms of fatigue can overlap with other hormonal concerns. Learn about the signs of hormone imbalance to better understand what your body may be telling you.
Hot flashes and night sweats can further disrupt sleep, creating a cycle where poor sleep contributes to daytime fatigue.
If you've also noticed irregular periods, mood changes, or changes in your sleep patterns, hormonal fluctuations may be contributing to how you feel.
Thyroid Health
Your thyroid helps regulate metabolism, energy production, and many other essential functions throughout the body.
When the thyroid becomes underactive, your body's processes slow down, which can lead to symptoms such as:
Persistent fatigue
Feeling unusually cold
Weight gain
Dry skin
Hair thinning
Constipation
Brain fog
These symptoms often develop gradually and may overlap with other health conditions, making thyroid disorders difficult to recognize without appropriate evaluation.
Your thyroid plays an important role in regulating metabolism and energy. Learn how to support thyroid health and why it matters for your overall wellbeing.
Nutrient Deficiencies
Your body depends on a steady supply of nutrients to produce energy efficiently.
Low levels of certain vitamins and minerals can contribute to fatigue, even if you're otherwise eating a balanced diet.
Some of the most common nutrient deficiencies associated with low energy include:
Iron
Vitamin B12
Vitamin D
Folate
Magnesium
Women may be at greater risk of these deficiencies due to heavy menstrual bleeding, dietary restrictions, digestive disorders, or changes in nutrient absorption with age.
Rather than taking supplements based on symptoms alone, it's best to speak with your healthcare provider about whether testing is appropriate for your individual situation.
More Factors That May Contribute to Fatigue
Persistent fatigue is often influenced by several interconnected factors rather than a single cause. Understanding these possibilities can help you and your healthcare provider determine the most appropriate next steps.
Chronic Stress and Burnout
Stress is a normal part of life, but when it becomes ongoing, it can take a significant toll on both your physical and mental wellbeing.
Chronic stress activates your body's stress response, making it harder to relax, sleep well, and recover. Over time, this can leave you feeling physically and emotionally exhausted, even if you're getting enough hours of sleep.
Signs that stress or burnout may be affecting your energy include:
Feeling overwhelmed by everyday responsibilities
Difficulty switching off or relaxing
Irritability or mood changes
Trouble concentrating
Feeling emotionally drained
Poor sleep quality
If these symptoms sound familiar, it's worth exploring whether stress management should be part of your overall wellness plan.
Blood Sugar Imbalances
Your body relies on a steady supply of glucose for energy. Large fluctuations in blood sugar levels can contribute to energy highs and lows throughout the day.
You may notice symptoms such as:
Mid-afternoon energy crashes
Feeling shaky or irritable when meals are delayed
Cravings for sugary foods
Difficulty concentrating before eating
Eating balanced meals that include protein, healthy fats, fibre, and complex carbohydrates may help promote more stable energy levels throughout the day.
If you have risk factors for diabetes or insulin resistance, speak with your healthcare provider about whether further evaluation is appropriate.
Inflammation and Autoimmune Conditions
Inflammation is a natural part of the body's healing process. However, when inflammation becomes persistent, it may contribute to ongoing fatigue and reduced quality of life.
Autoimmune conditions such as Hashimoto's thyroiditis, rheumatoid arthritis, and lupus commonly include fatigue among their symptoms.
Although fatigue alone doesn't indicate an autoimmune disease, persistent tiredness accompanied by joint pain, digestive symptoms, skin changes, or recurrent illness deserves further medical evaluation.
If you'd like to learn more about how inflammation affects overall health, read our article on The Brain-Immune Connection: What It Means for Your Health.
Mental Health
Mental health and physical health are closely connected.
Anxiety, depression, and prolonged emotional stress can all affect sleep, motivation, concentration, and energy levels. Likewise, persistent fatigue may increase emotional distress, creating a cycle that's difficult to break.
If you're experiencing ongoing low mood, excessive worry, or loss of interest in activities you usually enjoy, it's important to seek support from a qualified healthcare professional.
For practical ways to support emotional wellbeing, explore our article on Lifestyle Strategies That Support Anxiety and Depression Recovery.
Lifestyle Habits
Daily habits have a significant impact on your energy levels.
Fatigue may be influenced by factors such as:
Skipping meals
Eating a highly processed diet
Drinking too little water
Spending long periods sitting
Excessive alcohol intake
Smoking
Too much caffeine, particularly later in the day
While these habits may not be the sole cause of fatigue, improving them can support your overall health and complement other treatments where needed.
How Is Persistent Fatigue Evaluated?
Because fatigue has many possible causes, there isn't a single test that provides all the answers.
Your healthcare provider will usually begin by discussing:
Your symptoms and how long they've been present
Your sleep habits
Diet and nutrition
Stress levels
Physical activity
Medical history
Current medications
Family history
Depending on your symptoms, they may also recommend blood tests or other investigations to rule out common medical conditions.
These may include assessments for:
Thyroid function
Iron deficiency
Vitamin B12 and vitamin D levels
Blood sugar regulation
Markers of inflammation
Kidney or liver function
Other tests based on your individual health history
The goal is to identify potential contributors to your fatigue so that treatment can be tailored to your specific needs rather than relying on assumptions.
Lifestyle Strategies to Support Healthy Energy Levels
While treatment depends on the underlying cause of fatigue, healthy daily habits can help support your energy, recovery, and overall wellbeing.
Prioritize Quality Sleep
Aim for seven to nine hours of sleep each night and maintain a consistent sleep schedule, including weekends.
To improve sleep quality:
Keep your bedroom cool, dark, and quiet.
Avoid screens for at least an hour before bed.
Limit caffeine later in the day.
Develop a relaxing bedtime routine.
Eat Balanced, Nutrient-Dense Meals
Balanced meals help provide a steady supply of energy throughout the day.
Aim to include:
Lean protein
Whole grains
Healthy fats
Plenty of vegetables and fruit
Fibre-rich foods
Avoid skipping meals if you regularly experience energy crashes.
Stay Physically Active
Although exercise may feel challenging when you're tired, regular movement can actually improve energy levels over time.
Choose activities that suit your current fitness level, such as:
Walking
Swimming
Cycling
Yoga
Strength training
Start gradually if fatigue has limited your activity, and increase your exercise as your energy improves.
Make Time for Stress Management
Managing stress isn't just about feeling calmer—it also supports better sleep, emotional wellbeing, and overall health.
Consider incorporating practices such as:
Mindfulness or meditation
Deep breathing exercises
Journalling
Spending time outdoors
Connecting with family and friends
Taking regular breaks throughout the day
Even small changes can help improve resilience and support your body's natural recovery processes.
Recommended Supplements
While supplements may help address certain nutrient deficiencies or support overall health, they are not a substitute for a balanced diet, healthy lifestyle, or appropriate medical care.
Before starting any supplement, it's important to understand the underlying cause of your fatigue. Taking supplements without identifying the reason for your symptoms may not be beneficial and, in some cases, could be harmful.
Depending on your individual needs and laboratory findings, your healthcare provider may recommend:
Iron
Iron supports the production of healthy red blood cells, which carry oxygen throughout the body. If iron deficiency is contributing to fatigue, correcting the deficiency may help improve energy levels.
Iron supplements should only be taken after confirming a deficiency through appropriate testing, as excessive iron intake can be harmful.
Vitamin B12
Vitamin B12 plays an essential role in energy production, nerve function, and red blood cell formation.
People following vegetarian or vegan diets, older adults, and those with certain digestive conditions may be at a higher risk of deficiency.
Vitamin D
Vitamin D supports bone, muscle, and immune health. Low vitamin D levels are common and may contribute to fatigue in some individuals.
If deficiency is suspected, your healthcare provider can recommend appropriate testing and supplementation if needed.
Magnesium
Magnesium contributes to normal muscle function, nerve function, and energy metabolism. It also plays a role in supporting relaxation and healthy sleep.
While magnesium-rich foods should be the first choice whenever possible, supplements may be appropriate for some individuals.
Important: Supplement recommendations should always be personalized based on your symptoms, dietary intake, medical history, and laboratory findings.
When to Seek Professional Support
Feeling tired after a demanding week or a few restless nights is common. However, persistent fatigue deserves medical attention, particularly when it begins to affect your quality of life.
Consider speaking with a healthcare professional if you:
Feel tired most days for several weeks or longer.
Wake up feeling exhausted despite getting enough sleep.
Experience unexplained weight changes.
Notice changes in your menstrual cycle.
Have persistent brain fog or difficulty concentrating.
Experience dizziness, shortness of breath, or heart palpitations.
Develop new digestive symptoms.
Feel persistently low, anxious, or overwhelmed.
Have a personal or family history of thyroid disease, autoimmune conditions, or diabetes.
Seeking support early may help identify underlying health concerns before symptoms become more significant.
A Functional Medicine Perspective
Persistent fatigue is rarely caused by a single factor. Functional medicine recognises that low energy can result from the interaction of multiple body systems rather than one isolated issue.
Alongside conventional medical care, a functional medicine approach looks at your overall health to better understand what may be contributing to ongoing fatigue.
A comprehensive evaluation may consider questions such as:
Is poor sleep affecting your ability to recover?
Could hormonal changes be contributing to your symptoms?
Are thyroid function or blood sugar balance playing a role?
Are nutrient deficiencies affecting energy production?
Is chronic stress influencing sleep, mood, and overall wellbeing?
Are digestive health or inflammation affecting nutrient absorption and immune function?
Because every person's health history is unique, recommendations should be tailored to your symptoms, lifestyle, medical history, and appropriate laboratory findings.
The goal is to identify and address contributing factors while working alongside evidence-based medical care to support your long-term health and wellbeing.
Key Takeaways
Persistent fatigue is a symptom, not a diagnosis.
Hormonal changes, thyroid disorders, nutrient deficiencies, chronic stress, poor sleep, and blood sugar imbalances are among the many possible causes of fatigue.
Several factors often contribute to low energy at the same time, making a comprehensive evaluation important.
Healthy sleep habits, balanced nutrition, regular movement, and stress management can all support healthy energy levels.
Supplements should only be used when appropriate and ideally based on professional guidance and testing.
If fatigue persists despite healthy lifestyle habits, speak with a qualified healthcare professional to identify the underlying cause.
Frequently Asked Questions
Why am I always tired even though I sleep enough?
The amount of sleep you get is only one part of the picture. Poor sleep quality, hormonal changes, thyroid disorders, nutrient deficiencies, chronic stress, and underlying medical conditions can all contribute to fatigue, even if you're spending enough hours in bed.
Is fatigue a normal part of ageing?
No. Although energy levels can change with age, persistent fatigue should not be considered a normal part of ageing. Ongoing tiredness deserves evaluation to identify any underlying health concerns.
Can dehydration cause fatigue?
Yes. Even mild dehydration can affect concentration, physical performance, and energy levels. Drinking enough water throughout the day is a simple but important part of supporting overall health.
Should I take vitamins if I'm always tired?
Not necessarily. Fatigue has many possible causes, and taking supplements without identifying the underlying reason may not improve your symptoms. Speak with your healthcare provider before starting new supplements.
How do I know if my fatigue is related to my thyroid?
Fatigue caused by an underactive thyroid is often accompanied by symptoms such as feeling unusually cold, weight gain, dry skin, constipation, and brain fog. If these symptoms are present, your healthcare provider may recommend thyroid testing as part of your evaluation.
Final Thoughts
Feeling tired all the time isn't something you should simply accept or ignore. While busy schedules and occasional poor sleep can temporarily affect your energy, persistent fatigue may be a sign that it's time to take a closer look at your health.
Understanding what may be contributing to your fatigue is the first step. With the right evaluation and a personalised plan, many women can identify manageable factors that support better energy and wellbeing.
If fatigue persists despite making healthy lifestyle changes, seeking medical advice can help you better understand your symptoms and the next steps that may be appropriate.
If you've been experiencing persistent fatigue and aren't sure what's causing it, you don't have to navigate it alone.
At Dr. Vyas Health, we take a personalised functional medicine approach that considers your symptoms, lifestyle, nutrition, sleep, hormone health, and appropriate testing to identify factors that may be affecting your energy and wellbeing.
Book a consultation to discuss your health concerns and explore a personalized care plan.
References
National Institute for Health and Care Excellence (NICE). Clinical Knowledge Summary: Tiredness/Fatigue.
Centers for Disease Control and Prevention (CDC). Sleep and Sleep Disorders.
National Institutes of Health Office of Dietary Supplements. Vitamin B12 Fact Sheet.
National Institutes of Health Office of Dietary Supplements. Iron Fact Sheet.
National Institutes of Health Office of Dietary Supplements. Vitamin D Fact Sheet.
Related Articles
How to Support Thyroid Health and a Healthy Metabolism
13 Signs of Hormone Imbalance Most Women Ignore
Lifestyle Strategies That Support Anxiety and Depression Recovery
The Brain-Immune Connection: What It Means for Your Health
This article is intended for educational purposes only and should not be considered medical advice. It is not a substitute for professional diagnosis, treatment, or individualized healthcare recommendations. Always consult a qualified healthcare provider before starting or changing any treatment.
