The prospect of having an implantable cardioverter defibrillator (ICD) installed can be daunting news.
Nobody wants a slab of metal inserted into their chest, but once you educate yourself on ICDs and the conditions they treat, you will find that you can live a relatively normal life and do most things you did before having it installed – only with our the worry of an arrhythmia stopping you dead in your tracks.
Your heart beats in a controlled rhythmic manner in order to efficiently deliver blood—and the oxygen and nutrients it carries—to different parts of your body. Any disturbance in the heart’s electrical conduction system (arrhythmia) may compromise its ability to pump blood.
While some heart rhythm abnormalities like atrial fibrillation can be managed with anti-arrhythmic medications, in other cases, comparably more dangerous ventricular arrhythmias—irregularities propagated in the lower chambers of the heart—may require you to be fitted with an implantable cardioverter defibrillator.
What is an implantable cardioverter defibrillator?
An implantable cardioverter defibrillator is a small, thin, battery-powered device implanted just under the skin in the chest region (see image below) and is designed to deliver a shock to restore normal cardiac rhythm in those at risk for sudden cardiac death due to malignant arrhythmias like ventricular fibrillation or tachycardia.
These conduction disturbances may be the result of a heart attack, cardiomyopathy (diseased heart muscle), or a congenital defect, all of which can interrupt the normal electrical conduction pathways in the heart. While the implantable cardioverter defibrillator may be an inconvenience at first, many of the ICD patients I’ve worked with in cardiac rehabilitation adjusted their lifestyles and went on to live quite enjoyable and productive lives.
Short implantable cardioverter defibrillator video
If you learn more easily by watching videos, here is a very short 3D animated clip about ICDs which explains the procedure in very simple terms.
Can I exercise safely with an implantable cardioverter defibrillator?
When I teach fitness professionals about training clients with heart problems, invariably the question arises, “how do I exercise someone with an implantable cardioverter defibrillator?” My short answer is, not too differently from anyone else, except for several precautions (to be addressed below).
As a clinical exercise physiologist, I’m generally less worried about someone WITH an implantable cardioverter defibrillator because this tells me they’ve been diagnosed, treated, and are now under the care of a cardiologist.
It’s the person with malignant arrhythmias WITHOUT an ICD that keeps me awake at night! As stated above, your implanted cardioverter defibrillator is designed to “zap” you back to normal rhythm in the event your heart starts racing or beating erratically.
Exercise also causes your heart rate to increase, but this is a normal and expected response. So how does your implantable cardioverter defibrillator tell the difference between a potentially dangerous heart rate or rhythm versus normal exercise-induced increases in heart rate?
Generally speaking, your implantable cardioverter defibrillator will be programmed by your electrophysiologist to detect both abnormal heart rates and rhythms which are likely to be outside the range of what you’d accomplish with most daily activities or moderate exercise (which will minimize unnecessary or inappropriate shocks).
Your medical management team should give you safe exercise heart rate limits for your implantable cardioverter defibrillator settings. Your doctor may wish to carry out an exercise stress test to simulate your usual exercise intensity and “troubleshoot” any problems before they happen.
Tips for safe exercise with an ICD
The following tips will help you safely return to (or begin) an exercise regimen, but please understand these are general recommendations and are not a substitute for your doctor’s advice.
- First and foremost, before you start or return to your exercise regimen, it is absolutely imperative that you are medically stable, your implantable cardioverter defibrillator has been fitted and programmed, you’ve been educated on your specific condition and understand your ICD limits, and you are well-managed (i.e., medications like beta-blockers which preclude your heart rate from climbing too high).
- Wear an ID bracelet and have your implantable cardioverter defibrillator card with you at all times. It will inform those around you of your condition if you are unable to speak for yourself.
- Exercise with a friend or family member who is familiar with your condition and knows what to do in the event of an emergency.
- The ICD can be affected by magnetic or electrical fields. In the gym setting, bioelectrical impedance analysis (BIA) is a technology used for assessing body composition (percent fat, muscle, water). You should avoid this and opt for something simpler such as the sum of skinfolds. Heart rate monitors are unlikely to cause any problems in the gym setting.
- If you’re an athlete with a congenital heart defect and are accustomed to training and competing at high intensities, you should discuss your specific situation with your medical management team. They can adjust your implantable cardioverter defibrillator settings to recognize the difference between a normal increase in heart rate from exercise and that associated with an abnormal heart rate or rhythm. Clearly an ICD is not the most convenient gadget for playing sports, but it will significantly minimize the risk of sudden cardiac death.
Exercise prescription for implantable cardioverter defibrillator
The four fundamental components of an exercise prescription are easily remembered by the FITT acronym: Frequency, Intensity, Time (duration), and Type of exercise. So a basic exercise prescription for a person with an implanted cardioverter defibrillator might entail the following:
No matter if you’re new to exercise or are already a regular exerciser, after your implantable cardioverter defibrillator placement (and perhaps recovery from a heart attack or other health concern) you may feel a bit tired and lethargic. If so, congratulations, you’re human and completely normal.
I suggest easing into exercise with a three-day per week regimen at first, and slowly add on days as your body adapts and you feel stronger. In this case, I am referring to structured conscientious exercise with purpose. However, with regards to background activities,
I also encourage you to do daily incidental movement, such as walking to the corner shop for a liter of milk, down to the post office, etc. There is a lot of new evidence surfacing in the medical literature which shows this background activity plays an important role in both weight loss and weight management.
Intensity refers to how hard you’re exercising. Once you get your ICD implanted, you should ease into your routine. A sharp spike in heart rate could potentially set off your ICD. Therefore, you should include a low-level 5 to 10 minute warm-up and cool-down phase for aerobic exercise (i.e., walking, cycling) to allow for a slow and steady increase in heart rate.
After that, work up to a low to moderate intensity. A good pragmatic range is around 60 to 75% of your age-predicted max heart rate, but you can adjust this up or down depending on your relative fitness level and if it’s appropriate based on your physician’s advice.
In the exercise business, a best “guestimate” of your maximum heart rate is 220 minus your age. From this number, you then calculate a training heart rate range.
So if you’re 40 years old, then it’s 220 – 40 = 180 (theoretical max heart rate).
Next, 180 x 60% = 108 beats per minute and 180 x 75% = 135 beats per minute.
Therefore you would want to exercise in the range of 108 to 135 beats per minute.
If you have a hard time finding your pulse, get yourself a heart rate monitor or a Fitbit (which also tracks your non-exercise movement habits).
I have worked with numerous ICD patients who wore them and there is no concern of this interfering with the device. Check with your doctor if you have any questions.
The effects of beta-blocker medications
If you are taking beta-blocker medication, then your heart rate will remain blunted and will not fit neat and clean into the above heart rate calculation.
In this case, we like to use what is known as the Rating of Perceived Exertion (RPE). There are two RPE scales out there, so to eliminate confusion, I will use the 0 to 10 scale. In brief, 0 is sitting down at rest doing nothing and a 10 is an all-out effort to exhaustion.
Try to exercise at a “moderate” level, somewhere in the range of 4 to 6, and adjust based upon your body’s response. Also take note of your heart rate when you’re at a moderate workload. Though you’re on beta-blockers, this will reflect your individual response to exercise and can help serve as a guide.
If your dosage changes, then you may need to redo the above “experiment” to determine your new exercising heart rate. In my professional experience, people on beta-blocker medications will see a heart rate increase of approximately 20 to maybe 50 beats above rest, but again, this is variable and will likely reflect the dosage.
The length of your individual exercise sessions will vary, but as with the other exercise prescription components, you may want to start off on the low end and progress to longer durations as your fitness levels improve. For example, begin with a leisurely 15 to 20 minute stroll and see how your body responds.
Then work up to 30 minutes the following week, then 40 the week after, and so on. Pay particular attention to the terrain. Start off walking on level ground and, once your fitness foundation is established, you may want to experiment with some small hills (low incline).
Again, speak with your doctor regarding your exercise intensity and ICD limits. This knowledge will help you to tailor your exercise prescription and reduce any fear or anxiety over getting shocked during exercise.
Type of Exercise
In this day and age, there are a million and one different exercises you can choose from, but the good news is that most fall into several broad categories. The main types of exercise are aerobic, resistance training, and flexibility training. For the purpose of this article, I will only discuss aerobic and resistance exercise. Heavy duty power lifting or anaerobic interval training may not be conducive for individuals with an ICD (unless cleared by your doctor to do so).
Walking, bicycling, ellipitical trainer, rowing machine, dancing, aerobics classes, etc are all popular forms of aerobic exercise. Which is best? The one that you enjoy most and are most likely to remain consistent with!
Resistance training (weight lifting) with an ICD
There are mixed reviews on whether or not resistance training (weight lifting) is appropriate for people with an implanted cardioverter defibrillator.
Much of this confusion stems from the belief that heavy loads will place large demands on the heart which will cause an arrhythmia. While this is logical reasoning for very high intensity exercise, lifting lighter weights which do NOT leave you huffing and puffing and gasping for air are likely to be well-tolerated and can yield marked improvements in strength. This, in turn, will make daily living easier, thus reducing the likelihood that basic activities will not set off your ICD.
To begin, start off with a weight you can lift in the range of 10 to 15 repetitions. If new to weight lifting, begin with one set (i.e., one group of 10 to 15 repetitions) for the first couple of weeks and then graduate to two sets. It certainly won’t turn you into a muscled bodybuilder, but it is sufficient stimulus to confer appreciable improvements in strength. It is beyond the scope of this article to discuss every nuance of strength training, so I would suggest you hire a trainer for a few sessions to teach you proper form and technique.
Additional considerations for weight lifting exercise
- Avoid lifting weights so heavy that they leave you grunting, groaning, and gasping for air. This may increase the intrathoracic pressure, forcing your heart to work harder, and consequently set the stage for a possible arrhythmia (and subsequent shock). Rule of thumb: EXHALE ON THE EXERTION. In other words, when the weight is being lifted against gravity, exhale to release that internal pressure.
- Overhead lifting “may” put additional strain on your heart because it needs to pump blood “uphill” against gravity. You don’t necessarily need to avoid overhead movements, but may wish to use lower weights or do shoulder exercises like lateral raises or upright rows which minimize the overhead component. Bear in mind some overhead movements may aggravate the placement of your implantable cardioverter defibrillator, particularly if it was recently implanted. Stock standard advice: speak with your doctor for specific guidelines.
- Following on from above, in general, beware of exercises which might impact the physical placement of your implantable cardioverter defibrillator. For example, watch out for any exercises which incorporate the shoulder girdle/chest area where there is the risk of a weight or bar bumping into your implantable cardioverter defibrillator. If you’re doing flexibility exercises (i.e., yoga), be aware that certain movements could agitate the implantation site.
- Contact sports or other activities which could result in a jarring effect to your body are not recommended or should be judiciously engaged in ONLY with approval by your medical management team.
- If you participate in water sports, you should do so with an exercise buddy in case you receive a shock, feel dizzy or lightheaded, or are disoriented and unable to exit the water by yourself. SCUBA diving is generally discouraged, perhaps due to the risk of drowning (if you are rendered unconscious). Then again, the best advice is to seek the advice of your medical management team who will be most familiar with your unique situation and best qualified to give you specific guidance.
Take home message
Appropriate exercise specific to ICD implantation can enhance your overall well-being and quality of life. Regular training promotes healthy changes in the muscles and your collective cardiorespiratory (heart and lungs) system which, over time, makes your day to day living much easier.
Weight loss stemming from a healthy lifestyle reduces the overall load on the body and further reduces stress on your cardiovascular system. As a result, your heart will not have to work as hard to meet metabolic demands, therefore reducing the load on the heart and consequently lessening the chances of an arrhythmia—and a shock from your implantable cardioverter defibrillator. Now get out there and start living life again!