"I have no strength" is a general expression, which may refer to physical fatigue, weakness or illness. Here are some common situations that may lead to "no strength":

Physical fatigue: Long-term work, study or exercise makes the body tired, leading to muscle aches, weakness and other feelings.

Lack of sleep: Lack of sleep can lead to physical fatigue and lack of energy and motivation.

Malnutrition: unbalanced diet or insufficient nutrition intake will lead to the lack of energy and nutrition in the body, thus affecting the body's function.

Diseases: Some diseases such as anemia, cardiovascular diseases and muscle diseases can also lead to physical weakness or fatigue.

If you feel weak for a long time, I suggest you take a rest in time, adjust your work and rest, and keep adequate sleep and nutrient intake. If the symptoms persist or are accompanied by other uncomfortable symptoms, it is recommended to seek medical attention in time, conduct a comprehensive physical examination and diagnosis, so as to determine the specific cause and carry out corresponding treatment.