Do you only have enough energy until lunch? A professor explained why fatigue accompanies even those who live the healthiest lives

It seems the day started off well, in the morning there was energy, plans, and a desire to get more done. However, by lunchtime, you suddenly find yourself thinking not about work or a workout after work, but about coffee, something sweet, or simply a minute of sleep. This feeling is familiar not only to those who don’t get enough sleep or live chaotic lives – sometimes fatigue accompanies even those who, seemingly, are really trying to live more healthily.

Why does this happen, and why doesn’t another cup of coffee always help? This is explained by Prof. Arūnas Emeljanovas of the Institute of Health Sciences at the Faculty of Medicine, Vilnius University, and Lithuanian Sports University.

The “right” things don’t always work

It would seem that the more we move, take care of ourselves, and try to live healthier, the more energetic we should feel. However, it is not that simple. “Sometimes the problem is not that we do too little, but on the contrary – too much. This creates a perfect condition for fatigue to appear,” notes Prof. Arūnas Emeljanovas. According to him, physical activity itself is not the problem – on the contrary, it is one of the most important components of well-being. However, when movement becomes just another item on an already overloaded schedule and the body lacks rest and balance, even an active person can feel exhausted. Fatigue is often caused not by a single factor, but by a combination of them: constant pace, emotional stress, information overload from digital screens, and too little attention to recovery. This is why even a “healthy” person can feel tired.

Why do we have enough energy one day, but the next day we don’t

According to Prof. Arūnas Emeljanovas, our well-being depends not on a single factor but on a whole chain of processes in the body. “Energy is not just a feeling – it is a process. It depends on metabolism, the ability of cells to produce energy, and what we eat,” explains the professor. The body itself produces energy the question is how efficiently it does so, which is why many people experience not a constant lack of energy but fluctuations in it. “Energy ups and downs” are more common than we think: fast carbohydrates such as sugar and refined flour can provide quick energy, but this is often followed by a sharp drop and an “energy crash.” Therefore, the issue is often not a lack of energy itself, but its instability.

Coffee can help for a short time, but it does not always address the root cause

When energy starts to fluctuate, many people’s first instinct is to reach for another cup of coffee. It can indeed help you wake up or focus for a short time, but it often only masks the problem, and fatigue soon returns. “Coffee is not harmful, but it is not a long-term solution either. Its effect is short-lived, and if you drink it in the afternoon, it can worsen sleep and create a vicious cycle: poor sleep leads to more coffee, and too much coffee leads to even worse sleep. In other words, if fatigue repeats every day, coffee alone may no longer be enough,” says Prof. Arūnas Emeljanovas. He emphasizes that the issue is not energy itself, but its instability. One thing is to briefly ‘boost’ yourself, but something else entirely is to help the body function in a way that provides enough energy not just for an hour or two, but for the whole day. That is why more attention is now being paid not to quick fixes, but to supporting the body’s energy processes. In other words, the goal is not to raise energy temporarily, but to keep it more stable throughout the day.

What can actually help maintain energy

What can actually help maintain energy? According to Prof. Arūnas Emeljanovas, the foundation remains the same: sleep, nutrition, physical activity, and rest. However, it is also important whether the body receives enough substances involved in energy metabolism. The professor points out that certain amino acids are important, such as L-carnitine, arginine, and citrulline, as well as B-group vitamins, which can help maintain normal energy metabolism and reduce fatigue and feelings of tiredness. Amino acids are naturally obtained from food and are found in a variety of everyday products: L-carnitine in meat, fish, and dairy products, arginine in meat, nuts, legumes, and seeds, and citrulline in watermelons, melons, and some animal products. In practice, these substances are often combined, and such combinations are most commonly associated with maintaining more stable energy in an active daily life.

When should fatigue not be ignored

Feeling tired after a few more demanding days is normal, but if fatigue is constant, it is worth taking it more seriously. The professor follows a simple “one-week rule”: if feeling unwell lasts 2–3 days, there is no need to worry yet, but if it does not pass within a week, it is a signal to stop and reassess the situation. Ultimately, the key question is no longer “how to quickly regain energy,” but how to maintain it throughout the day consistently, not just temporarily. “Energy is a system that can function well or poorly. Sometimes the problem is not that we do too little or too much. Sometimes it is that we do not provide the body with what it truly needs,” says Prof. Arūnas Emeljanovas.