When you get sick — a run-of-the-mill illness, like a cold or the flu — you may have noticed your heart beats a little faster than normal. In that moment, perhaps you even got a bit nervous. You may have asked yourself, “why is my heart beating so fast?” or “should I call a doctor about it?”
It’s totally normal to have an increased heart rate when you’re sick. Most of the time, it’s not a cause for concern. When you get sick, your body temperature usually rises, and that makes your heart beat faster. However, to better understand exactly what’s going on, we spoke with Pratik Dalal, MD, a cardiologist at Banner Health, to discuss the connection between sickness and your heart rate. Here’s what you should know.
Is my heart rate normal?
According to the American Heart Association, a normal resting heart rate for most adults is somewhere between 60 and 100 beats per minute (bpm). For athletes and those who are generally more active, that heart rate may be as low as 40 bpm. When you’re sick, that bpm is likely a bit higher.
Kids usually have a higher heart rate than adults. The National Institutes of Health (NIH) outlined the following average resting heart rates for children:
- Newborn to 1 month: 70-190 bpm
- 1 to 11 months: 80-160 bpm
- 1 to 2 years: 80-130 bpm
- 3 to 4 years: 80-120 bpm
- 5 to 6 years: 75-115 bpm
- 7 to 9 years: 70-110 bpm
- 10 years and older: 60-100 bpm
To check your heart rate, start by finding your pulse on the inside of your wrist. Then use the tips of your index and middle finger to press lightly over the artery. Count your pulse for 30 seconds, then double that number to find your bpm. Other health monitoring tools, like wearable fitness trackers or a stethoscope, can also help here.
If your heart rate is consistently above or below these target ranges, and you are showing the following symptoms, you should see a doctor:
- Shortness of breath
- Fainting spells
- Light-headedness or dizziness
- Fluttering or palpitations in the chest
- Chest pain/discomfort
While it’s common for people to worry about an elevated heart rate, there’s often nothing wrong, You should always get professional medical advice whenever you’re concerned about why it’s happening, Dr. Dalal advised.
Why does my heart rate increase when I’m sick?
When your body temperature goes up, so does your heart rate. And since sickness often means a fever, that means a faster heartbeat goes right along with it.
Dr. Dalal said medical professionals describe this in terms of “cardiac output,” or how much blood the heart is pumping per minute.
“If a person’s physical demands for more blood increases, then the heart rate is generally the first to increase to meet that demand,” he explained. Things like fever, hyperthyroidism, pain, illness and exercise cause the heart rate to increase in order to give the body the blood it needs for these more demanding situations.
Dehydration is also a common reason your heart rate may go up. When your body is low on fluids, this decreases your body’s volume of blood and plasma. This makes your heart pump faster to send this smaller amount of oxygenated blood to your other organs and tissues that need it.
Dr. Dalal said he always recommends water without any additives for hydration. Using caffeinated beverages for this purpose is a bad idea, he explained. Caffeine can be a diuretic — meaning it makes you urinate more — which isn’t what you want when you’re rehydrating.
What else can affect my heart rate?
A number of other factors may impact your heart’s resting bpm, such as the following:
- Body weight
- Emotions (anxiety or excitement)
- Endocrine or hormonal abnormalities
- External temperatures
- Medication side effects
- Postural orthostatic tachycardia syndrome (PoTS)
Have concerns about your heart rate?
If you’d like to learn more about common heart issues, read these articles written with help from Banner Health experts.
- Should You Be Concerned About Your Heart Palpitations?
- Understanding Heart Arrhythmias
- Interpreting Symptoms of a Heart Murmur
- Heart Rate Training: Getting in the Zone
- How Atrial Fibrillation Could Affect Your Heart's Health
Minor updates were made to this article content on February 5, 2024.