Fatigue

Fatigue is a normal and important signal from the body. It indicates that energy has been used and that recovery is needed. Everyone feels tired sometimes, for example after a busy working day, an intensive training session or a period of little sleep. In such situations, fatigue is functional: it helps you to take rest and gives the body the chance to recover.

It becomes a problem when fatigue persists or no longer subsides properly after rest. In that case we speak of overfatigue. This is occurring more and more often and has a major impact on daily functioning. Fatigue can be both physical and mental. Sometimes the fatigue is short term and sometimes it is present for a long time.

How fatigue works

To understand why we become tired, it is important to know how the body handles energy. Almost everything we do requires energy: not only moving, but also thinking, the functioning of organs and maintaining the body itself. We obtain this energy from nutrients such as carbohydrates, fats and proteins, which are converted into fuel for our cells.

During the day, part of that energy reserve is depleted and processes in the brain change. For example, the amount of adenosine increases, a substance that intensifies the feeling of sleepiness. At the same time, melatonin plays a role in the sleep-wake rhythm: this hormone ensures that we become sleepy in the evening. During sleep, these processes are, as it were, "reset" and energy reserves are replenished.

When the body is put under extra strain, for example by intensive sport, illness or prolonged stress, more time is also needed to recover. If that recovery time is lacking, fatigue builds up.

Physical and mental fatigue

Physical fatigue arises after physical exertion. Think of sport, heavy work or a long day of being active. The muscles then use energy and small changes occur in the muscle tissue. This is a normal reaction of the body. This usually recovers on its own within a few hours to days.

Mental fatigue feels different. It mainly arises from prolonged concentration, stress or a high cognitive load, such as during a busy working day with many stimuli. Notably, you can then feel tired even though your body has not been heavily physically loaded. The exact cause of this is complex, but it has to do, among other things, with changes in the brain and reduced efficiency of mental processes during prolonged exertion.

What many people notice is that movement actually helps with mental fatigue. A walk or bike ride clears the head again. This is because blood flow to the brain improves and substances are released that positively influence energy levels and mood.

Short-term and long-term fatigue

After a day of exertion, it is normal to be tired. This short-term fatigue usually disappears after a good night's sleep. During sleep, the body recovers, energy reserves are replenished and important processes in the brain and muscles are regulated.

Sometimes, however, fatigue remains, even after sufficient rest. If this lasts longer than a few months, we speak of long-term or chronic fatigue. The body then seems no longer able to recover properly. This can have various causes, such as persistent stress, sleep problems, illness, poor nutrition or a long-term imbalance between load and recovery. Both physical and mental factors often play a role.

Fatigue, illness and stress

Fatigue is a common symptom during illness. When the body has to fight an infection or another condition, that costs a lot of energy and tiredness develops. You see this, for example, with flu, but also with conditions such as diabetes, anaemia or thyroid problems.

In addition, stress plays a major role. In an acute situation, stress is useful: the body prepares to act and to release energy. But when stress is present for a long time, the body remains in a kind of "on" mode. That constantly costs energy and hinders recovery. This can eventually lead to chronic fatigue.

Recovery: the key to less fatigue

To reduce fatigue, recovery is essential. Sleep plays the biggest role in this. During sleep, the body has the chance to replenish energy and recover from the strain of the day. But recovery is broader than sleep alone.

Relaxation during the day is also important. This does not necessarily mean doing nothing, but activities that cost little energy or actually give you energy, such as walking, reading or spending time with others. In addition, regular movement helps the body to function well. Movement stimulates blood flow and supports recovery, as long as there is a sufficient balance with rest moments.

What can you do about fatigue?

With fatigue, it is especially important to look at the balance between what costs energy and what provides energy. A regular sleep rhythm, healthy nutrition and sufficient movement form the basis. Even though it sometimes feels counterintuitive, light exercise often helps you feel more energetic.

When fatigue persists and does not improve, it is wise to consult your GP. Sometimes additional tests are needed to rule out physical causes, such as vitamin or mineral deficiencies or other medical problems.