When your heartbeat changes, you may or may not become aware of it. It is not uncommon to have the beat flutter a bit after exercise, but that doesn't mean you should disregard the skipping. The best option is to talk to your doctor to make sure your heart is in good shape.
How Exercise Affects the Heart
When you exercise, the muscles send a message to the brain requesting oxygen. The brain then sends a signal that the body is being stressed and the heart responds by pounding harder to oxygenate the tissue. You start breathing more deeply to bring in more oxygen and remove carbon dioxide. As the exercise intensifies, the heart increases the speed to keep up with the need for oxygen. This is a normal process and part of the reason why you exercise: The heart is a muscle and needs the workout just as much as the other muscles in the body.
During and after exercise, you may feel your heart palpitate; this is common. Palpitations occur when you sense your heart flutter for a second or two. Within the beat, there may be an occasional skip. The exact reason this happens is unclear, but most palpitations are harmless. As you relax after the workout, your brain will send a message that the stress is easing. The heart will begin to slow and return to the normal sync, so the palpitations will stop.
An arrhythmia is a little different from a palpitation. Inside the heart is a bundle of nerves known as the sinoatrial node. This is the heart's pacemaker, and an arrhythmia is a glitch in the pacemaker wherein the sinoatrial node begins to have problems regulating the heartbeat. The signals from the brain reach the node, but the node cannot interpret or respond appropriately. A palpitation is an event, something that "just happens." An arrhythmia is a condition; it doesn't just happen. With an arrhythmia, there is a mechanism in your heart that is not working properly. Palpitations can be a sign of an arrhythmia, but can also be a response to something else.
How to Tell When You Have a Problem
You may not be able to tell the difference between a true arrhythmia and a basic palpitation, but your doctor can. If you feel skipping in your heart after exercising, this is not a reason to panic. However, if the skipping is accompanied by pain in your arm, chest or jaw, you need to seek help. Additional symptoms such as pain, nausea, dizziness, shortness of breath or feeling faint are all signs of something bigger. If you are unsure, don't ignore a potential warning sign -- call for help.