You should visit your doctor if your heart rate is consistently above 100 beats per minute or below 60 beats per minute (and you’re not an athlete), or you’re also experiencing:
- shortness of breath
- fainting spells
- lightheadedness or dizziness
- feeling fluttering or palpitations in your chest
- having pain or discomfort in your chest
- an inability to exercise
A person’s heart rate may become dangerous if it is too high or too low. However, many factors can affect when a heart rate is dangerous.
The heart rate changes throughout the day to accommodate the demands of the body. It is higher during times of intense activity and lowest when a person relaxes or sleeps.
The heart rate also changes during pregnancy, fever, and times of anxiety.
Identifying a person’s usual heart rate pattern can help them understand what a dangerous heart rate is for them personally.
A person should undergo regular checks to determine their heart rates at rest and while exercising. This could help them understand if there are any changes in their heart rate that could be dangerous.
A normal resting heart rate is 60–100 beats per minute (bpm) for most adults.
However, some people have heart rates outside of these ranges and are still perfectly healthy. For example, an elite athlete might have a very low resting heart rate of 40 bpm.
The heart rate greatly increases when a person is very active or exercising.
The highest rate a person’s heart can safely reach is their maximum heart rate. This declines with age. The ideal heart rate, or target heart rate, for exercise also declines with age.
In general, for most adults, the target and maximum heart rates are as follows:
A person’s heart rate increase during exercise depends on many factors, including how intense the workout is and how fit they are.
A very sedentary person might find that their heart rate increases when walking from one room to another.
People who exercise regularly may need very intense workouts to get their heart rate up.
If a person’s heart rate is temporarily outside of these numbers during exercise, it is not usually a medical emergency. According to the AHA, a person can push themselves a little more or less depending on their heart rate target.
For most people, their sleeping heart rate will fall to the lower end of the normal resting heart rate range of 60–100 bpm.
In deep sleep, the heart rate may fall below 60 bpm especially in people who have very low heart rates while awake.
After waking, a person’s heart rate will begin increasing toward their usual resting heart rate.
What can influence the heart rate?
Many different factors can influence a person’s heart rate.
In most cases, having a very high or very low heart rate is only dangerous when there is not an obvious explanation.
High heart rate
Some factors that may cause a high heart rate include:
- Anxiety: People who are experiencing intense anxiety may have heart rates higher than 100 bpm, especially during a panic attack.
- Pain: Pain can cause the heart rate to climb much higher.
- Pregnancy: A person’s heart rate increases if they are pregnant. Normal activities also require more cardiovascular effort, so a person may find that relatively easy activities such as climbing stairs or taking short walks can cause the heart rate to climb much higher than usual. Pregnancy may also cause heart palpitations or an irregular heart rate.
- Fever: A fever can sometimes cause a higher heart rate. A person may also have a higher heart rate in intense heat.
- Caffeine: Caffeine increases both heart rate and blood pressure. If a person has recently had caffeine and notices a higher heart rate, this might be why.
- Medications: Some medications, such as serotonin or attention deficit hyperactivity disorder drugs, may also change the heart rate. Call a doctor if the heart rate suddenly changes after taking a new medication.
It is important to keep in mind that panicking about having a high heart rate may cause it to become even higher. Taking a few deep breaths and trying calming exercises may help a person assess whether or not their heart rate really is dangerous.
If there is an obvious cause of a heart rate change, such as pain or a fever, try addressing that first to see if the heart rate returns to normal.