Lack of energy: possible causes, warning signs and solutions to get back in shape

A lack of energy isn't "all in your head": it's a signal. It can stem from insufficient sleep, prolonged stress, an unsuitable diet… or reveal a deficiency (iron, vitamins, magnesium) or even an underlying medical problem. The goal of this guide is simple: to help you identify the most likely cause and implement a concrete action plan to regain stable energy levels—no miracle cures, just a structured and reliable approach.

Understanding your lack of energy: normal fatigue or a symptom to investigate?

The 3 most common profiles

• Occasional energy dip : end of the day, after a meal, after a bad night's sleep.
• Persistent fatigue (≥ 2–3 weeks): low energy almost daily, decreased motivation and concentration.
• Unexplained/unusual fatigue : sudden, intense, associated with new symptoms (aches, pain, shortness of breath, fever, weight loss).

Quick self-check (in 2 minutes)

Answer “yes/no”:

1. I sleep less than 7 hours or my sleep is not restorative.
2. I am stressed/anxious most days.
3. I skip breakfast or I often snack on sweets.
4. I drink little / dark urine.
5. I do little physical activity (less than 2 hours/week).
6. I get out of breath easily, pale, brittle nails (iron track).
7. I feel cold, have gained weight, and have dry skin (possibly related to the thyroid).
8. I snore / daytime sleepiness (apnea possible).

The more boxes you tick, the more likely lack of energy multifactorial (often 2–4 cumulative causes).

The most common causes of low energy (and what to do about it)

1) Insufficient or non-restorative sleep (cause #1)

Typical signs: waking up during the night, difficulty falling asleep, “I sleep but I am exhausted”.

Effective actions (starting tonight):

1. Fixed wake-up time (same weekend): stabilizes the biological clock.
2. Daylight 10–20 min in the morning: synchronizes the circadian rhythm.
3. Stop coffee/tea after 2pm (sensitivity varies).
4. Eat a lighter dinner earlier (avoid large late meals).
5. Room: cool, dark, quiet (sleep hygiene).

Common mistake: compensating with more coffee → improves short-term alertness but degrades sleep and perpetuates the fatigue cycle.

2) Chronic stress, mental workload, anxiety

Prolonged stress is exhausting: constant tension, fragmented sleep, rumination. It is cited as a major factor in fatigue and lack of energy .

“Anti-exhaustion” protocol (10 min/day):

• 3 minutes: slow breathing (6 cycles/min).
• 5 minutes: walk without phone.
• 2 minutes: write down “the 3 priorities” (reduces cognitive overload).

To watch out for: irritability, concentration problems, loss of motivation — if it lasts, support (doctor/psychologist) is relevant.

3) Diet: Blood sugar rollercoaster + protein deficiency

Common profile: sweet breakfast / irregular meals → postprandial drowsiness, cravings.

Simple optimization (quick effect):

• At each meal: 1 portion of protein (eggs, fish, legumes, tofu, Greek yogurt).
• Add fiber (vegetables, oats, legumes) to smooth out blood sugar levels.
• Smart snack: a handful of nuts + fruit (instead of biscuits).

4) Dehydration and electrolyte imbalance

Even insufficient hydration can cause decreased energy, headaches, and reduced performance.

Practical guideline: urine is clear to pale yellow most of the time.

Tip: 1 large glass upon waking + 1 before each meal = simple base.

5) Sedentary lifestyle: the less you move, the less energy you "produce"

Paradoxical but classic: inactivity perpetuates fatigue.

Minimal plan (without heroic motivation):

• 7 days: 10 minutes of walking per day.
• Then: 20 minutes, 5 days a week.
• Add 2 sessions/week of strengthening (bodyweight): improves tone and sleep.

Deficiencies and lack of energy: when to consider them (and how to act)

Iron deficiency (low ferritin): common, especially in women

Possible signs: paleness, shortness of breath on exertion, brittle nails.

Good reflex: do not self-supplement “at random” → request a check-up (CBC, ferritin) via a professional.

B vitamins: fatigue, "dead battery", low energy

B vitamins (B2, B3, B5, B6, B9, B12) are often cited for their role in reducing fatigue.

Risk factors: diet low in animal products (B12), digestive disorders, certain medications (to be discussed with a doctor).

Magnesium: fatigue + nervousness + light sleep

Persistent fatigue may be associated with a magnesium deficiency (with cramps, irritability, etc.).

In terms of formulations, bisglycinate is often highlighted as well tolerated and well absorbed for fatigue/stress/sleep.

Important: a supplement may help, but if the cause is sleep/stress/diet, it will not “fix” it on its own.

Vitamin D: seasonal fatigue and diffuse pain (possible cause)

More common in winter or with low sun exposure. A blood test can guide appropriate supplementation.

When a lack of energy should prompt a consultation (warning signs)

Check quickly if you have:

• Abnormal shortness of breath, chest pain, significant palpitations
• Prolonged fever, night sweats
• Unintentional weight loss
• Sudden and intense unexplained fatigue
• Severe depression, dark thoughts
• Significant daytime sleepiness + loud snoring (suspected sleep apnea)

Tests that are often useful (to be discussed with a doctor)

• NFS + ferritin (iron)
• TSH (thyroid)
• Vitamin B12/B9
• Vitamin D
• Blood glucose/HbA1c depending on context
• Sleep evaluation if apnea is suspected

30-Day Action Plan to Regain Stable Energy

Week 1: Quick recovery (foundations)

1. Fixed sunrise + morning light.
2. Coffee only in the morning.
3. 10 minutes of walking per day.
4. 1 meal/day “anti-energy slump”: protein + vegetables + whole grain starch.

Weeks 2–3: Stabilize (metabolism & stress)

• 2 strengthening sessions/week (20–30 min).
• Breathing 10 min/day.
• Structured hydration (automatic lenses).
• Eat dinner earlier + reduce screen time 60 minutes before bed.

Week 4: Optimize (what makes the difference)

• Adjust your diet (less ultra-processed, more fiber).
• Work on regular sleep patterns.
• If fatigue persists despite a healthy lifestyle: medical check-up .

FAQ 

Why do I lack energy every day?

The most common causes are poor sleep, chronic stress, a diet that causes blood sugar fluctuations, dehydration, and a sedentary lifestyle. If this lasts more than 2–3 weeks, a check-up may be helpful.

What is the cause of the extreme fatigue and lack of energy?

Stress and anxiety can lead to general fatigue and lack of energy . Other common causes include sleep deprivation, iron deficiency, thyroid disorders, and sleep apnea.

What vitamin is lacking when you are tired?

B vitamins (B2, B3, B5, B6, B9, B12) are often associated with reducing fatigue. Vitamin D is also a potential factor, depending on the context (seasonality, exposure).

What are the symptoms of an iron and magnesium deficiency?

Iron deficiency can manifest as paleness, shortness of breath on exertion, brittle nails; magnesium deficiency as cramps, palpitations, irritability.

Which magnesium is best for chronic fatigue?

Magnesium bisglycinate is often cited as a well-absorbed and useful form for fatigue, relaxation, and sleep. Consult a doctor if you are undergoing treatment, are pregnant, have kidney disease, etc.

Conclusion

Lack of energy most often has a combined origin: sleep + stress + diet + physical activity, sometimes aggravated by a deficiency (iron, vitamins B/D, magnesium). Start with the 30-day plan (regular sleep, daily walks, more consistent meals, stress management). If fatigue persists beyond 2–3 weeks or is accompanied by warning signs, move to the next step: a targeted medical evaluation to treat the underlying cause, not just the symptom.