Why are you always tired, and what are the causes of fatigue in men over 40? Are you a man wondering if you’re doing enough to stay healthy as you age? Have you ever skipped a check-up, delayed getting tested, or assumed feeling “fine” meant everything was okay? If you’re in your 20s, 40s, 60s or anywhere in between, this article is for you. It’s designed for men who want to take a more proactive role in their health but aren’t sure where to start.
In this guide, we break down what health screenings you should be doing, when to do them, and why they matter. With early detection often making the difference between simple treatment and serious complications, knowing what to test and when can help you prevent illness, catch problems early, and lead a longer, more energetic life.
Are you a man over 40 who’s constantly asking yourself, “Why am I so tired?” Do you wake up feeling drained, push through the day on low energy, or find it harder to focus and stay motivated than you used to? If you’ve chalked it up to ageing or a busy life, you’re not alone, but you might be overlooking deeper causes.
This article is for men in their 40s and beyond who are feeling persistently fatigued and want real answers. We’ll explore the most common lifestyle, mental health, and medical reasons for low energy in men, and explain why understanding these factors can help you regain your strength, clarity, and vitality. If you’re tired of feeling tired, keep reading.
Causes of Fatigue in Men
We all get tired from time to time; a busy day, a late night, or a restless sleep can leave you feeling sluggish. But what happens when that tiredness never quite goes away? When no matter how much you rest, you’re still dragging yourself through the day?
If you’re a man over 40, constantly feeling run down, unfocused, or lacking motivation, it’s not just “getting older.”
It might be your body telling you something important. At Nuffield Clinic, we take these symptoms seriously and help men get back to feeling like themselves again.
Difference Between Fatigue and Sleepiness
Before diving deeper, it’s important to understand the difference between fatigue and sleepiness. They may feel similar, but are actually quite different. Sleepiness, also known as somnolence, is that drowsy, nodding-off feeling that usually comes from not getting enough sleep or being bored. It’s generally resolved by rest.
Fatigue, on the other hand, is a persistent and often overwhelming sense of tiredness that doesn’t go away even after a good night’s sleep. It’s more than just being sleepy; it’s a lack of energy and motivation that affects your ability to concentrate, work, exercise, and even enjoy life. It can make ordinary tasks feel like a mountain to climb.
So, what causes this deeper form of exhaustion?
Lifestyle Factors That Drain Your Energy
For many men, especially those in their 40s and beyond, fatigue stems from the pressures of daily life. Work stress, financial responsibilities, family commitments, and trying to stay healthy can all take a toll.
One major culprit is poor sleep quality. Even if you’re technically in bed for 7 or 8 hours, factors like late-night screen use, inconsistent sleep schedules, noise, light, or uncomfortable room temperature can all interfere with the restorative stages of sleep. Disorders like insomnia, restless legs syndrome, or sleep apnea, where your breathing is briefly interrupted during the night, can leave you feeling completely unrefreshed the next day.
Another often overlooked factor is diet. Skipping meals, eating mostly processed or carb-heavy foods, or relying on sugar for quick energy can lead to what many call the “afternoon slump.” That post-lunch crash happens when your blood sugar spikes and drops quickly, leaving you feeling foggy and lethargic. Not drinking enough water, even just mild dehydration, can also significantly reduce your energy levels.
We can’t forget about caffeine and alcohol. While coffee may perk you up temporarily, too much can lead to jitteriness followed by an energy crash. Alcohol may seem relaxing, but it disrupts your deep sleep, often causing you to wake up during the night without realising it.
Ironically, both too much and too little exercise can leave you exhausted. Being sedentary lowers your overall stamina, but overtraining without proper rest can deplete your body’s energy reserves and lead to chronic fatigue. Striking a balance with moderate, regular activity is key.
Lastly, body weight plays a role, too. Being overweight or underweight can put stress on your body’s systems. Eating disorders, even those that go unrecognised, such as undereating or purging, can also lead to severe energy depletion.
Mental Health and Fatigue
Stress isn’t just in your head; it can wear your entire body down. Chronic stress triggers the release of cortisol and other stress hormones from your adrenal glands. Over time, this constant demand can lead to a condition some refer to as “adrenal fatigue,” where the glands struggle to keep up. The result? Feeling constantly wired yet tired, anxious, but unable to focus.
Depression is another common but often under-recognised cause of fatigue in men. You might not feel sad or tearful, but you may notice you’re sleeping more (or less), losing interest in things you once enjoyed, and struggling to stay motivated. Depression can drain your energy and cloud your ability to think clearly.
Anxiety, whether it’s generalised worry or social anxiety, can be exhausting too. When your brain is constantly “on alert,” your body remains in a state of high tension, making true rest and relaxation nearly impossible.
Even seasonal affective disorder (SAD), a form of depression linked to changes in seasons, can cause noticeable dips in energy, especially during darker winter months.
When Fatigue Signals an Underlying Medical Condition
Sometimes, persistent fatigue is a sign of something deeper. Several medical conditions can leave you feeling flat, even if you think you’re otherwise healthy.
A common and often missed cause is iron deficiency. Iron helps your body make red blood cells, which carry oxygen. If you’re low on iron, even without full-blown anaemia, you might feel dizzy, breathless, and easily fatigued. Men who don’t eat much red meat, vegetarians, or those with digestive issues are at higher risk.
Another key player is your thyroid, a small gland in your neck that regulates metabolism. When it’s underactive (hypothyroidism), everything slows down, including your energy levels. Men with hypothyroidism may also experience weight gain, cold intolerance, constipation, dry skin, and even low mood. On the flip side, an overactive thyroid (hyperthyroidism) can leave you feeling jittery, sweaty, and weak, but still tired due to disrupted sleep and muscle breakdown.
Diabetes, especially when undiagnosed, can lead to unrelenting fatigue, thirst, frequent urination, and blurred vision. It’s becoming more common in men over 40, and early signs are often missed until a major energy crash occurs.
Vitamin deficiencies, particularly Vitamin D, Vitamin B12, and magnesium, are also major contributors to fatigue. These nutrients help convert food into energy, support brain function, and regulate muscle and nerve health. If you’re low, you’ll feel it.
Men’s hormones play a role, too. Testosterone levels naturally decline with age, but when they drop too low, men can experience a noticeable loss of vitality. Fatigue, loss of muscle mass, increased body fat, lower libido, erectile dysfunction, and even mild depression can all point to low testosterone, also known as andropause or “male menopause.”
Lastly, more complex or chronic conditions like chronic fatigue syndrome (ME/CFS), fibromyalgia, heart failure, autoimmune conditions, or postural orthostatic tachycardia syndrome (POTS) can all manifest as extreme tiredness, often with other puzzling symptoms like brain fog, dizziness, or pain.
When Should You See a Doctor?
If you’ve tried improving your sleep, eating better, and managing stress but still feel constantly worn out, it’s time to speak to a healthcare professional. Don’t wait until the fatigue becomes unbearable.
Warning signs that warrant a doctor’s visit include:
- Unexplained weight loss
- Night sweats
- Fever
- A persistent cough
- Coughing up blood
- Changes in bowel habits
- Heavy periods (in women), or for men, unusually pale complexion or dizziness
- Feeling hopeless, low, or anxious most days
At Nuffield Clinic, we approach fatigue not as a symptom to dismiss, but as a clue to uncover the deeper story behind your health. We offer a full evaluation that includes detailed medical history, lab testing (such as blood sugar, thyroid levels, ferritin, Vitamin B12 and D), and referrals to trusted specialists when needed. For sleep concerns, we can arrange sleep studies. For hormonal imbalances, we assess and guide treatment, including testosterone therapy if appropriate.
How We Help You Regain Your Energy
At Nuffield Clinic, our expert team provides holistic, evidence-based care for men experiencing fatigue, stress, and low energy. Our personalised treatment approach includes:
- Optimising your sleep routine: Helping you build better habits, improve your sleep environment, and address possible sleep disorders.
- Tailoring a nutritious, sustainable diet: Guiding you toward balanced meals that fuel your day without blood sugar crashes.
- Supporting exercise and physical therapy: Whether you’re overdoing it or not doing enough, we help you strike the right balance.
- Managing stress through proven techniques like mindfulness, breathwork, and lifestyle coaching.
- Identifying and treating deficiencies and hormone imbalances with targeted supplements or therapies.
- Providing emotional and psychological support, including referrals for therapy if depression or anxiety is suspected.
Whether your fatigue is caused by lifestyle issues, mental health, or a medical condition, we’re here to help you take control of your health and feel vibrant again.
Feeling constantly tired is not normal. You don’t have to settle for just getting through the day.
Contact Nuffield Clinic today to schedule a comprehensive men’s health assessment. Let us help you identify the root cause of your fatigue and create a plan to restore your energy, motivation, and quality of life.
