Figure 1: Normal sinus rhythm and atrial fibrillation of the heart
Abnormal heart rhythm (atrial fibrillation) and exercise:
An Exercise is Medicine Fact Sheet
What is an abnormal heart rhythm or atrial fibrillation?
The Technical Explanation!
Atrial fibrillation (AF) is a common and important disturbance of the electrical system of the heart. It is one type of a number of disorders termed ‘arrhythmias’ or ‘dysrhythmias’, where the heart beats in an abnormal rhythm. An abnormal heart rhythm can lead to significant problems such as stroke and heart failure. AF can be identified by irregular ‘fluttering’ of the heart and also general feelings of dizziness, weakness, fatigue, exercise intolerance or discomfort. AF can be identified as being either ‘stable’ or ‘unstable’.
Figure 1 shows the heart in normal sinus rhythm compared to the heart in atrial fibrillation. When healthy, the heart is a highly efficient pump. It has four chambers, two that receive oxygen-poor blood from the body and then pump it to the lungs and two that pump oxygenated blood to the rest of the body.
The larger lower chambers (‘ventricles’) receive blood from the upper chambers (‘atria’) and play the role of pumping blood throughout the body. In a heart with normal sinus rhythm, the atria contract first, prior to the ventricles contacting. This process occurs around 60 to 100 times per minute.
This contraction of the atria is initiated by tiny electrical signals that come from the heart’s natural ‘pacemaker’, the sinus (SA) node. These signals are then passed to the ventricles via the atrioventricular (AV) node, which cause the ventricles to contract shortly after being filled with blood from the atria. This rhythm is termed ‘sinus rhythm’ because it is controlled by the sinus node.
More about AF
AF occurs when the electrical signals in the atria are abnormal. ‘Waves’ of uncontrolled electrical signals travel through the atria, rather than the normal regulated signals from the sinus node. Often these signals are initiated in the pulmonary veins, the veins that bring blood from the lungs into the heart.
This abnormal wave signals cause the muscle fibres in the atria to work out of rhythm with each other. This is termed ‘fibrillation’. These signals can then be passed onto the ventricles which can cause a rapid and irregular heartbeat, leading to inefficient operation of the heart.
How does exercise help?
Abnormal heart rhythm can be managed and you can continue to lead a healthy lifestyle. As AF can be associated with other forms of cardiovascular disease (e.g. high blood pressure, coronary heart disease – clogging of the arteries, heart valve issues or hyperthyroidism), it is important to reduce the risk of these conditions through lifestyle changes. Avoiding smoking, healthy dietary habits, physical activity, controlling blood pressure and maintaining a healthy body weight are all ways to minimise risk of heart issues.
What are the recommendations for exercise?
The recommendations for physical activity for people with stable AF are similar to those with other cardiovascular diseases. You need to speak to your doctor about the risks of any changes in activity.
Referral to an appropriately trained and qualified exercise professional (e.g. accredited exercise physiologist) can help determine the type and amount of exercise that may be most appropriate. People on certain medications such as Warfarin (blood thinner) should avoid activities where they may be at an increased risk of excessive bleeding.
In order to reduce cardiovascular risk, people with high cholesterol should aim for aerobic exercise for at least 30 minutes on most, if not all, days of the week. A useful strategy of doing so may doing shorter bouts of 10 minutes at a time and building up. Examples of aerobic exercise are brisk walking, jogging, cycling, swimming dancing, ball games or other sporting activities. A good way to determine exercise intensity is to exercise at an intensity where you can maintain a conversation without getting too short of breath.
Resistance training (weights) can also help to reduce the risk of cardiovascular issues. Generally 2-3 sets of 8-10 different exercises at a moderate level of intensity (able to do 8-12 repetitions), twice a week can help to improve CV risk. It is advisable to start with a general aerobic warm up of 5-10 minutes prior to carrying out resistance training. The trick is to ensure appropriate technique is used for each exercise to reduce the risk of injury.
Self-administered vigorous aerobic or resistance training may not be suitable for people with unstable AF. People with an abnormal heart rhythm who would benefit from a structured program delivered by an accredited exercise physiologist (AEP) include:
• anyone with known CV disease, metabolic syndrome or diabetes
• people with a family history of CV disease
• a person with hypertension (high blood pressure)
• men aged over 45 years and women aged over 55 years
• any person who has not been doing regular physical activity or exercise.
How can we help?
The myPhysioSA fitness and rehabilitation team accredited exercise physiologists (AEPs) can help you with your goals to reduce your cardiovascular risk, including aiming to lower your lipid and lipoprotein levels.
This can be one-to-one through a range of referral pathways including Medicare and through your private health insurance.
Accredited exercise physiologists (AEPs) are skilled in determining exercise prescription specific to your needs. You may be able to participate in a group class where you exercise alongside people with similar cardiac risk factors. If you would like further information, please do not hesitate to contact us at myPhysioSA.
References and further information:
Exercise is Medicine Australia www.exerciseismedicine.org.au
Find an Accredited Exercise Physiologist www.essa.org.au
Exercise Right www.exerciseright.com.au
Heart Found website: https://www.heartfoundation.org.au
Stephen Bateman Accredited Exercise Physiologist