Normal Body Temperature: What You Need to Know

Our body temperature plays a significant role in maintaining our overall health and well-being. It is an essential indicator of the body’s internal conditions and can reveal important information about our state of health. In this article, we will explore the concept of normal body temperature, its significance, and how it can vary from person to person.

Body Temperature

Understanding Body Temperature

Body temperature refers to the measurement of the heat produced by the body. It is influenced by various factors, including metabolism, physical activity, hormone levels, and the external environment. The human body has a remarkable ability to regulate its temperature through a process called thermoregulation.

The Average Normal Body Temperature

For many years, it was commonly believed that the average normal body temperature was 98.6°F (37°C). This value was established by a German physician named Carl Reinhold August Wunderlich in the 19th century. However, more recent studies have shown that normal body temperature can vary among individuals and should be considered within a range rather than a specific value.

Normal Body Temperature Range

The normal body temperature range for a healthy adult is typically considered to be between 97°F (36.1°C) and 99°F (37.2°C). It is important to note that individual temperatures can fluctuate throughout the day, influenced by factors such as time of day, physical activity, and hormone levels. Additionally, certain conditions and medications may also affect body temperature.

Factors Affecting Body Temperature

There are several factors that can affect body temperature and cause it to deviate from the normal range. These include:

1. Time of Day

Our body temperature tends to be lower in the morning and slightly higher in the late afternoon and evening. This natural variation is influenced by our circadian rhythm, the internal biological clock that regulates our sleep-wake cycle.

2. Physical Activity

Engaging in physical activity can cause our body temperature to rise temporarily. Exercise generates heat within the body, increasing the overall temperature. This is why individuals who have recently exercised might feel warmer than usual.

3. Hormonal Changes

Hormonal changes, particularly in women, can influence body temperature. For example, during ovulation, a slight increase in body temperature is common. This can be used as a natural indicator for tracking fertility.

4. Illness or Infection

When the body is fighting off an illness or infection, it often responds by raising its temperature. This elevated body temperature, known as a fever, is a sign that the immune system is working to combat the invaders.

5. External Environment

Extreme weather conditions, such as hot or cold temperatures, can impact body temperature. In cold weather, the body may constrict blood vessels and shiver to conserve heat, while in hot weather, it may sweat to cool down.

Measuring Body Temperature

There are several methods for measuring body temperature, each with its own advantages and limitations. The most common methods include:

1. Oral Thermometers

Oral thermometers are placed under the tongue and provide a convenient and non-invasive way to measure body temperature. However, they may not be suitable for individuals who have difficulty keeping their mouth closed or who have recently consumed hot or cold substances.

2. Rectal Thermometers

Rectal thermometers are inserted into the rectum and provide an accurate representation of core body temperature. This method is commonly used for infants and young children who are unable to hold an oral thermometer in their mouth.

3. Ear Thermometers

Ear thermometers measure body temperature by detecting the infrared heat waves emitted by the eardrum. They are quick and easy to use, but their accuracy can be affected by earwax buildup or improper positioning.

4. Forehead Thermometers

Forehead thermometers use infrared technology to measure body temperature from the temporal artery in the forehead. They are non-invasive and provide quick results, but their accuracy may vary.

Abnormal Body Temperature

An abnormal body temperature can be an indication of an underlying health issue. A fever, for example, is often a sign that the body is fighting off an infection. Conversely, a lower-than-normal body temperature may be a symptom of hypothermia or an underactive thyroid gland.


Understanding normal body temperature and its variations is crucial for monitoring our health and recognizing potential abnormalities. While the average normal body temperature is approximately 98.6°F (37°C), it’s important to remember that individuals can have slightly different ranges. Factors such as time of day, physical activity, hormonal changes, and illness can all influence body temperature. By being aware of these factors and regularly measuring our body temperature, we can better assess our overall health and seek prompt medical attention if necessary.

Frequently Asked Questions (FAQs)

Can body temperature vary throughout the day?

Yes, body temperature can vary throughout the day. It tends to be lower in the morning and slightly higher in the late afternoon and evening due to our circadian rhythm.

What is considered a fever?

A fever is generally defined as a body temperature above 100.4°F (38°C) in adults. It is often a sign that the body is fighting off an infection.

How can I measure body temperature accurately?

To measure body temperature accurately, it is recommended to use a reliable thermometer and follow the instructions provided by the manufacturer. Different methods, such as oral, rectal, ear, or forehead thermometers, have varying levels of accuracy.

What should I do if my body temperature is outside the normal range?

If your body temperature is outside the normal range and you are experiencing other symptoms, it is advisable to consult a healthcare professional. They can assess your condition, identify any underlying health issues, and provide appropriate treatment.

Can stress affect body temperature?

Yes, stress can affect body temperature. In response to stress, the body releases stress hormones that can impact its temperature regulation. This can lead to symptoms such as increased sweating or feeling hot.

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