What Causes a Low Temperature?

A low body temperature can be normal for some people, but it can also be a sign of a problem.

For most adults, a normal body temperature is between 97.8 degrees F to 99.1 degrees F. Some people naturally register lower than this, but low body temperature can also indicate a medical condition like thyroid disease that may need treatment. If your body temperature drops below 95 degrees F, it can indicate hypothermia, a serious condition that requires immediate medical attention.

This article covers some possible low body temperature causes, how to take your temperature correctly, and when to seek medical care for a low body temperature.

Causes: Why Is My Temperature Low?

Having a slightly lower body temperature is not always a concern.

For example, body temperature decreases with age due to fat loss. A low temperature can also be due to the use of certain medications, hormonal and metabolic changes, and natural fluctuations throughout the day.

That said, a body temperature lower than 97.8 degrees F can sometimes be a sign that something’s wrong. Some of the medical conditions that can cause a low body temperature include:

• Underactive thyroid (hypothyroidism)
• Low blood sugar (hypoglycemia)
• Circulation problems
• Dehydration, as well as not eating enough and drinking alcohol
• Vitamin deficiency, typically iron levels and vitamin B12
• Sepsis (a type of bodywide infection)
• COVID-19 infection

Temperatures nearing or dipping below 95 degrees can indicate that hypothermia is developing or has set in. This typically happens when someone is exposed to cold air or water for a period of time (e.g., they have fallen in a frozen lake).

Hypothermia can also be caused by necessary medical treatment, like surgery. Sometimes, providers lower a person's body temperature on purpose to try to save them after severe trauma.

Mild to Serious Symptoms of a Low Temperature

A body temperature that's slightly below normal may not cause any symptoms aside from feeling chilly, although the underlying cause may bring about other symptoms.

When your temperature approaches or dips below 95 degrees F, however, you’ll experience the signs and symptoms of hypothermia.

The first signs that your body temperature is too low are typical responses to cold, for example, you'll have chills and start shivering.

When hypothermia becomes severe, you may stop shivering. As hypothermia progresses, you will be unable to think clearly or move.

The signs and symptoms of hypothermia include:

• Confusion
• Drowsiness
• Cold, pale skin
• Slow heart rate and breathing
• Uncontrolled shivering, then not shivering at all
• Loss of coordination
• Weakness

When to See a Healthcare Provider

If you don't have hypothermia but consistently have a body temperature below 97 degrees F, or you constantly feel cold, talk to your healthcare provider.

How to Tell If Your Temperature Is Low

If you take your body temperature and are worried that it's too low, you first need to make sure the reading you got is correct and that you've considered factors that may affect it.

Consider When You Take a Reading

Don't take your temperature immediately after doing certain activities. For example:

• Within an hour of exercise or a hot bath
• Within 30 minutes of smoking
• Within 30 minutes of drinking a hot or cold drink

Read the instructions for your thermometer and follow them. Most thermometers will beep when it's time to check the reading.

Take Thermometer Differences Into Account

Your thermometer reading will depend on which part of the body you took the reading from. In general, a rectal temperature reading is considered most accurate and closest to your body's core temperature.

Other readings, such as an ear or armpit temperature, are less accurate peripheral readings, especially in people experiencing fever or hypothermia.A review of 75 studies found these readings often exceeded an acceptable range of 0.5 degrees in variation. Oral thermometers fared best in this group.

The COVID-19 pandemic broadened the use of infrared temperature sensors, but these readings also vary based on skin tone and the location of the body. Wrist readings, for example, were consistently lower than forehead readings. Researchers determined that a reading at the temples that captures blood in the temporal artery is closest in accuracy to a rectal (core) temperature.

Summary

Having a low body temperature is not always a problem. Some people naturally have a lower-than-normal body temperature, especially as they get older.

A body temperature that is too low, however, can be a sign of a health condition or even a life-threatening emergency.

If you have a consistently low body temperature and you feel cold all the time, it's best to bring it up with your provider. They can figure out if there's a medical cause for your low body temperature and make sure you get the right treatment.