Quick version
Before you look for quick fixes, you should review your sleep, fluids, and regular meals with protein and fiber. If fatigue persists, there may be an underlying deficiency in iron, B12, folate, or vitamin D, which can be easily diagnosed with a blood test.
Getting into the second breath after the holidays can be surprisingly tough, even when you've been going for a couple of weeks and the autumn routines should have settled in. You may still be struggling to sleep, putting off lunch because your meeting calendar is full and feeling like your brain is shutting down as early as three o'clock. When you don't have enough energy during the autumn, it pays to go back to the basics of your body's energy system: prioritized sleep, enough fluids and regular meals. If persistent fatigue still refuses to go away, it may also be wise to check if there is a nutritional deficiency behind it, such as a lack of iron or vitamin B12.
Back to work - fill up on this to boost your energy levels
Wanting to boost energy levels is rarely about "eating something magical". Instead, fatigue is often the body's way of signaling that recovery, nutrition or blood values are not quite up to par. For those who return to work after a break, the load becomes clear: the brain needs to switch gears, routines need to return and sleep often needs to be adjusted again.
Boost energy levels with regular meals, protein and iron-rich foods
Many people are looking for the perfect food to lift energy dips, but it is rarely a matter of quick solutions. The body feels best with a steady supply of nutrition rather than long meal breaks and occasional boosts. By choosing meals that combine protein, high-fiber carbohydrates or whole grains and healthy fats, you will feel fuller for longer and have a more stable energy level during the afternoon - something coffee and sweet snacks rarely manage to provide in the long run.
In practice, this can mean yogurt with nuts and berries for breakfast, a lunch with fish or beans and whole grain rice, or a sandwich with eggs instead of just grabbing a coffee on the go. For many, a planned snack also works better than waiting until blood sugar and concentration have already dropped. It is not a laboratory test that determines whether lunch was too small, but the body quickly notices it in the form of brain fatigue, irritability and snacking.
Iron deserves its own place when talking about energy. Iron is needed for hemoglobin, the protein in red blood cells that transports oxygen to the body's tissues. In the case of iron deficiency or iron deficiency anemia, common symptoms are fatigue, lack of energy, shortness of breath, palpitations and paleness.
Iron-rich foods may be particularly relevant for people with heavy menstruation, pregnant women, blood donors, endurance athletes and people who eat little or no meat. Examples of iron sources are meat, legumes, green leafy vegetables and iron-fortified products. At the same time, tea, coffee and large amounts of dairy products in connection with meals can impair iron absorption.
This does not mean that all tired people should start taking iron tablets on their own. Iron deficiency should preferably be confirmed with testing, often with a blood count and ferritin, since fatigue has many causes and incorrect treatment can cause you to miss something more important. A complete blood count and ferritin are two central tests when investigating long-term fatigue and needing to rule out other conditions.
Don't forget the fluids - mild dehydration often feels like a lack of energy
Many interpret low energy as a need for more food, when the problem is actually too little fluid. Dehydration can cause fatigue, headaches, dizziness, difficulty concentrating and a general feeling that the body is moving slowly. A simple guideline is that urine during the day should usually be light colored.
After vacation, everyday life is often more governed by meetings, commuting and fixed times. Then it is easy to drink coffee but forget about water. Caffeine can temporarily increase alertness, but it does not replace fluids, sleep or nutrition. If you notice that your head gets heavy in the afternoon, your mucous membranes dry or you barely have time to go to the toilet during the day, fluid intake is a reasonable thing to start with.
For most people, having water easily available and tying drinking to routines, such as a glass in the morning, with each meal and between two meetings, is enough. In hot weather, physical activity or a lot of sweating, the need increases. Here the solution is often less dramatic than many people think: regular fluid intake beats “rescue drinking” late in the day.
When fatigue is due to vitamin deficiency: B12, folate and sometimes vitamin D
If you eat properly but still feel unusually weak, a deficiency state may be part of the explanation. Vitamin B12 and folate are needed for the normal formation of red blood cells. Deficiency can cause weakness and fatigue, but also shortness of breath, palpitations, decreased appetite and sometimes cognitive problems. In case of B12 deficiency, the nervous system can also be affected with numbness, tingling, balance problems or memory impairment.
B12 deficiency is seen more often in people who eat a vegan diet without supplements, the elderly, people with diseases of the stomach or intestines and in some people who use medications that affect absorption. Therefore, it is not always enough to just “eat a little better” if the deficiency does exist; The cause sometimes needs to be investigated and the treatment can be tablets or injections depending on the background and symptoms.
Vitamin D is often discussed in connection with fatigue, but it is important to be careful here. Vitamin D deficiency can occur, especially with low sun exposure, old age or certain risk factors, but there is no strong evidence for general screening of symptom-free adults.
The practical message is therefore: test specifically, not casually. If you have clear fatigue, muscle pain, limited sun exposure or other risk factors, a vitamin D test may be relevant, but it should be placed in a larger context together with symptoms and other blood tests.
Sleep is still the most underestimated source of energy
When you want to get back into the work rhythm, it is tempting to look for supplements first. But for adults, lack of sleep is one of the most common explanations for both physical and mental fatigue. Adults generally need at least 7 hours of sleep per night, and for many a working range is around 7–9 hours. Too little sleep impairs concentration, memory, reaction time and mood.
This is clearly noticeable in the first few weeks back at work after a day off. Later evenings during the summer, more screen time or early commutes can cause the body to be a step behind from the morning onwards. If you are tired, you should try to keep regular sleep times and avoid food, caffeine, hard exercise and screens close to bedtime.
Movement gives more energy than it takes – especially after sedentary days
It sounds contradictory to use energy to get more energy, but it is true for many. Regular physical activity improves fitness, sleep, stress management and perceived energy. It is recommended that adults get at least 150 minutes of moderate physical activity per week, as well as muscle-strengthening activity at least two days a week.
For those who feel sluggish after the holidays, the starting distance does not need to be advanced. Even a 15-minute walk can provide an immediate energy boost, and regular exercise reduces fatigue in the long term. This makes a big difference for those who sit still all day and experience that their energy drops as the day goes on.
Here, small, concrete solutions often work better than ambitious plans. Walking meetings, a brisk lunch walk, stairs instead of the elevator and short strength training at home can be more than enough to break the sedentary lifestyle. The goal is not perfection, but to help the body return to a state where sleep, appetite and alertness interact better.
When should you suspect that low energy is not just “back to work”?
If fatigue persists despite better sleep, food and fluids, it is reasonable to think more broadly. Testing is particularly relevant if you also have shortness of breath, palpitations, paleness, dizziness, numbness, tingling, memory impairment or if you belong to a risk group for iron or B12 deficiency. In this case, self-care as the only strategy is not enough.
Long-term fatigue can also be related to stress, depression, sleep problems, infection, thyroid disorders or other medical conditions. Therefore, blood tests become valuable when the symptoms do not fit into a simple pattern. A well-thought-out test package can provide answers whether the body lacks building blocks for oxygen transport, nerve function or recovery.
The most useful approach is to see energy as a biological receipt, not as a question of character. When the body does not deliver energy, there is often an explanation that can be influenced - but the right action starts with the right cause.
