It's normal for your heart rate to fluctuate throughout the day as you go through your day-to-day activities, which may include both sitting and watching TV to running on a treadmill. If your heart rate elevates for no reason, even when you're just sitting, this is called tachycardia and can be a serious condition that causes serious symptoms. If you suspect you have this condition, see your doctor right away.
A high heart rate can make you feel suddenly dizzy. When your heart beats faster than it should, it will pump more blood. If blood is rushing to your brain, it can make you feel lightheaded and dizzy. Vertigo is another common problem associated with tachycardia, according to MedlinePlus.
A high heart rate may also produce palpitations. Palpitations is the feeling of your heart thumping against your chest. Normally, you are not aware of your heart beating, but if your heart rate is too high, you might hear your heartbeat in your ears very loudly.
Shortness of Breath
When your heart rate is higher than it should be, you may experience shortness of breath, according to the Mayo Clinic. This is the sensation of not being able to catch your breath, even when you are sitting still and have not exerted yourself. If you're not getting enough air, you may feel dizzy, hyperventilate or pass out.
Pain and Other Symptoms
If your heart is beating very quickly, it could be a sign of serious issues, especially if it is accompanied by pain, according to the Heart Rhythm Society. Pain in your chest or feelings of pressure could be a sign of a heart attack. Other symptoms that can accompany a high heart rate that may be serious include changes in vision and fatigue.