We all have days when we feel drained — after long hours, skipped meals, or restless nights. But when tiredness becomes a regular part of your life, even when you think you’re doing everything right, it may be time to look beyond coffee and sleep schedules. According to Dr. Antti Rintanen, a doctor and founder of The Internet Doctor, persistent fatigue often has much deeper roots connected to blood health, nutrition, and everyday habits.
Why Energy Levels Drop
Low energy is one of the most common health complaints, but it rarely has just one cause. Sleep, stress, hydration, and nutrition all play a role in how energetic — or exhausted — one feels. When something disrupts the body’s balance, it starts sending signals: brain fog, irritability, and the feeling that even simple tasks take extra effort.
While lifestyle is often a factor, blood health can also have a big influence. Your blood delivers oxygen and nutrients to every cell in your body. If that system isn’t working efficiently, your muscles, brain, and organs don’t get the fuel they need.
The Hidden Connection Between Blood and Fatigue
Most people associate blood tests with illness, but even healthy individuals can learn a lot from them. A routine blood test can reveal whether your red blood cells are carrying enough oxygen or if you might be lacking key nutrients.
One of the markers doctors pay attention to is the MCV (Mean Corpuscular Volume), which measures the average size of red blood cells. Abnormal MCV values can be a sign that your cells aren’t functioning optimally — for instance, if you’re low in certain vitamins or minerals.
- Low MCV (microcytic anemia) means your red blood cells are smaller than normal. This is often caused by iron deficiency, which limits the blood’s ability to transport oxygen. People with low MCV may experience fatigue, dizziness, or pale skin.
- High MCV (macrocytic anemia) means your red blood cells are larger than normal. This can happen when your body lacks vitamin B12 or folate, both essential for red blood cell formation. Other causes include excessive alcohol intake, liver disease, or thyroid imbalance. You can learn more about the causes and management of high MCV in Dr. Rintanen’s detailed guide.
Everyday Habits That Drain Your Energy
Even without a diagnosed condition, small daily habits can have a big impact on how your body manages energy. Some of the most common culprits include:
- Skipping meals or relying on processed foods. Quick carbs give short bursts of energy, but they also cause crashes later in the day.
- Not drinking enough water. Dehydration slows circulation and oxygen delivery. Even mild dehydration can make you feel sluggish.
- Prolonged stress raises cortisol, a hormone that helps regulate energy and metabolism. When cortisol stays elevated for too long, it disrupts how your body processes which contribute to both mental and physical fatigue.
- Irregular sleep schedules. Poor sleep reduces red blood cell production and disrupts hormone balance.
- Lack of physical activity. Regular movement boosts circulation and helps the body use oxygen more efficiently.
The good news? Each of these can be improved with small, sustainable changes.
Simple Tips to Support Blood and Energy Health
Dr. Rintanen recommends building your energy from the inside out. These evidence-based habits support better blood quality, oxygen flow, and nutrient absorption — all essential for lasting energy.
1. Eat iron-rich foods.
Iron helps your body make hemoglobin, the protein that carries oxygen in the blood. Include spinach, lean meat, beans, and fortified cereals in your diet.
2. Prioritize B-vitamins.
Vitamin B12 and folate are crucial for red blood cell formation. They’re found in fish, eggs, and dark leafy greens. Vegans and vegetarians may need to monitor these levels more closely.
3. Stay hydrated.
Water supports nutrient delivery and circulation. Aim for at least six to eight glasses a day — more if you’re active.
4. Keep a regular sleep routine.
Your body repairs and regulates itself at night. Going to bed and waking up at consistent times can stabilize hormone levels and energy output.
5. Move a little every day.
Light exercise like walking, cycling, or stretching increases oxygen flow, helping blood cells perform efficiently.
When to Get Checked
If fatigue lingers despite healthy habits, you shoudn’t ignore it. A simple blood test can reveal nutrient deficiencies, hormonal imbalances, or anemia — all of which are treatable once identified. Dr. Rintanen notes that “understanding your blood values gives you real control over your health. You don’t have to guess why you feel tired — your body might already showing you the clues.”
The Takeaway
Energy isn’t just about willpower or motivation — it’s about biology. Your blood is the body’s transport system for oxygen and nutrients, and when it’s off balance, everything feels more difficult. The encouraging part is that small adjustments — eating better, resting well, staying hydrated — can dramatically improve how you feel.
If you’ve been running on empty, take it as an invitation to check in with your body. With the right care and understanding, fatigue doesn’t have to be your baseline — your energy can return, naturally and steadily.
