Suddenly feeling cold and shivering at night, but it gets better after a while—what could be the cause?

Generally, sudden shivering at night that resolves shortly afterward may be related to decreased environmental temperature, upper respiratory tract infection, anemia, hypoglycemia, hypothyroidism, or other causes. Patients should seek timely medical evaluation at a正规 hospital and receive appropriate treatment based on the underlying condition. Specific analyses are as follows:

1. Decreased Environmental Temperature

If body metabolism slows during sleep, a low ambient temperature at night may disrupt thermal balance, leading to chills and shivering. This is a physiological response that typically improves once adequate warmth is provided.

2. Upper Respiratory Tract Infection

This is usually caused by bacterial or viral infections. When an upper respiratory tract infection occurs, pathogens can impair immune and nervous system functions, resulting in symptoms such as chills and shivering, often accompanied by coughing, nasal congestion, and similar manifestations. It is recommended that patients take medications such as acetaminophen tablets, oseltamivir phosphate capsules, or ribavirin tablets under medical guidance to alleviate symptoms.

3. Anemia

Anemia refers to insufficient quantity or quality of red blood cells, reducing the blood’s ability to transport oxygen. Oxygen deficiency may cause feelings of coldness, especially at night. Some patients may also experience dizziness and fatigue. Treatment may include iron supplements such as ferrous sulfate tablets, ferrous succinate tablets, or ferrous fumarate tablets, as directed by a physician. In severe cases, blood transfusion may be necessary.

4. Hypoglycemia

If a patient eats too little during dinner or receives excessive insulin injection, blood glucose levels may drop too low, causing symptoms such as weakness, palpitations, and tremors. Consuming sugary foods like chocolate, candy, or honey can help relieve symptoms. Additionally, treatments such as glucose-sodium chloride injection, Ejiao Blood Enriching Granules, or Shengmai Drink may be used as directed by a doctor.

5. Hypothyroidism

Hypothyroidism is a metabolic disorder caused by insufficient secretion of thyroid hormones, impairing the body's ability to generate heat effectively. At night, when the body is at rest, patients may feel unusually cold, accompanied by shivering, fatigue, memory decline, constipation, and other symptoms. Treatment typically involves taking medications such as levothyroxine, thyroid tablets, or hydrocortisone tablets under medical supervision.

In daily life, patients should maintain healthy lifestyle habits and avoid excessive fatigue to prevent worsening of their condition.