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Heart Attack (Myocardial Infarction) Exercise Guidelines

Heart Attack (Myocardial Infarction) Exercise Guidelines

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A heart attack, shorthand speak for a myocardial infarction, is a life-altering event that may lead to significant anxiety which can compromise your quality of life.

In my previous posts on exercise for angioplasty/stentcoronary artery bypass surgery, heart valve surgeryimplanted cardioverter defibrillator (ICD), and atrial fibrillation, I lightly touched on heart attacks and how the exercise “playing field” changes after you’ve had one. 

But I’d like to assure you that once you’ve had a heart attack, your life is NOT over. Pretty far from it.

As a clinical exercise physiologist working in cardiac rehabilitation and research settings, I’ve worked with a lot of people who’ve had heart attacks and, with proper treatment and follow-up exercise therapy, they’ve gone on to live very active and productive lives.

It amazes me that some people I’ve worked with who’ve had quite large heart attacks actually had no real understanding of exactly what a heart attack is. 

And this lack of awareness only served to make them more anxious and afraid to do any physical activity.

For some, it became an excuse to exclude themselves from life (“Oh, I can’t do that, I have a bad ticker…”). 

But ‘learned helplessness’ is learned and can also be unlearned!

What Exactly Is a Heart Attack?

It is important to understand that the heart is a pump which circulates blood throughout the body. 

The heart must also pump oxygen and nutrient-rich blood to itself which it does through the coronary arteries (see image below).

Coronary arteries are a network of blood vessels which wrap around and envelop the heart muscle.

A heart attack, or myocardial infarction (MI), occurs when there is a blockage in the coronary arteries that feed blood to the heart muscle.

The ‘downstream’ heart muscle below the blockage is starved of oxygen and nutrients and, unless medical treatment is administered immediately, it can result in death of the heart muscle served by that artery.

heart attack myocardial infarction
Photo credit: National Heart Lung Blood Institute

Short Animated 3D Video About Heart Attacks

If you’re partial to learning by videos, I found this short clip about heart attacks with 3D animation which succinctly summarises the process.

What is the Difference Between Angina and a Heart Attack?

When a coronary artery has a blockage, this can lead to chest pain, commonly referred to as angina

But the blockage does not have to be 100%.

In many cases, it is possible to have, say, a 70% blockage in an artery and have no symptoms whatsoever at rest. 

Under exertion, such as when walking up a hill or some other sort of strenuous activity, the heart muscle’s demand for blood (and the oxygen and nutrients it carries) is exceeded by the coronary arteries’ ability to supply it.

For most people, this results in the standard tell-tale symptoms like jaw, chest, back, or arm pain, sweating, lightheadedness, dizziness, or other atypical pain (i.e., referred pain to the low back).

The good news is that this is only a plumbing problem in your coronary arteries and NOT a heart attack (though can turn into a heart attack if left unattended). 

Often when you stop exercise, the pain will go away.

If the pain is predictably consistent with activity, then it is known as stable angina.

Alternatively, when you’re sitting at home in your chair watching TV and the chest pain kicks in without warning, this is known as unstable angina.

Obviously the latter is more critical, but both situations warrant immediate medical attention.

What are the Signs and Symptoms of Angina?

  • Chest pain or discomfort (sometimes mistaken for heart burn)
  • Shortness of breath
  • Pain radiating down the left arm (or both arms), the back, neck, jaw, or the abdominal area
  • Feeling queasy/nauseous, vomiting, cold sweat, dizziness
  • Atypical pain which might occur in between the shoulder blades or in the lower back (not common, but I’ve seen it in clinical practice)

A heart attack, on the other hand, occurs when the blood flow through a coronary artery is completely blocked.

This may occur suddenly when a blockage in the artery ruptures and the impending blood clot impedes blood flow.

In other cases, an abnormal cardiac rhythm can cause the heart to stop, but this is not the same as ischemic heart disease (blocked arteries).

For people with underlying cardiac risk factors, such things like shovelling snow or playing a ‘weekend warrior’ game of football can precipitate a heart attack.

Time is Heart Muscle: Quick Treatment Saves Lives

The onset of angina is your cue to get to the hospital as soon as possible. 

In cardiac rehab, we have a saying which goes “time is heart muscle.”

The quicker they evaluate you, administer clot busting drugs, and/or perform an emergency angioplasty (or bypass surgery), the more likely you are to preserve your heart muscle.

How do you know you’re at risk for a heart attack (or second heart attack)? 

Be aware of the following cardiovascular risk factors which may predispose you to heart problems:

What Are My Risk Factors for a Heart Attack?

The American College of Sports Medicine’s Guidelines for Exercise Testing and Prescription is the bible for exercise physiologists and provides excellent information on exercise after a heart attack.

List of Cardiovascular Disease Risk Factors

Age

Male: 45 years or older; Female: 55 years or older

Family History

Heart attack, coronary artery bypass surgery, or sudden death in an immediate blood relative (before age 55 in male 1st degree relative or before age 65 in female relative)

Cigarette Smoking

Current smoker or those who quit within the past 6 months. Click here for information on how cigarettes affect your blood vessels.

High Blood Pressure

Systolic blood pressure of 140 mmHg or diastolic blood pressure of 90 mmHg or greater confirmed by measurements on at least two separate occasions, or taking prescribed blood pressure medication.  This Mayo Clinic article discusses the impact of blood pressure on your heart and body.

Sedentary Lifestyle

Not participating in at least 30 minutes of moderate intensity physical activity on at least three days of the week for at least three months

Obesity

Body mass index of 30 kg/m2 or greater or waist measurement of 40 inches or greater (> 102 cm) for men and 35 inches or greater (>88 cm) for women. This article in the cardiologist journal Circulation discusses the link between obesity and heart disease.

High Cholesterol

Total cholesterol is 200 mg/dl or greater (5.18 mmol/l); LDL cholesterol is 130 mg/dl or greater (3.37 mmol/l); or HDL is less than 40 mg/dl (1.04 mmol/l)

Pre-diabetes

Glucose levels after an overnight fast are between 100 to 126 mg/dl  (5.5 to 6.93 mmol/l) or glucose levels after a 75g oral glucose tolerance test  are between 140 to 200 mg/dl (7.7 to 11 mmol/L).  There is a strong link between diabetes and cardiovascular risk.  If you HAVE diagnosed diabetes, you are at a 2-4 times greater risk of heart attack and stroke.  Keep your blood glucose levels under control.

Protective HDL Levels

HDL is your “good” cholesterol which protects you against heart disease.  A level of 60 mg/dl (1.55 mmol/l) is desirable

For more information on diet after a heart attack, read Gabby Maston’s article on the paleo diet vs. the Mediterranean diet.

Should I Do Cardiac Rehabilitation After a Heart Attack?

Being a former cardiac rehabilitation exercise physiologist, I admit I’m biased when it comes to recommending cardiac rehab after a heart attack.  

But I cannot overemphasize it enough:  GO TO CARDIAC REHAB.

Most programs will provide you with three key elements for long-term success:

  1. Detailed education about your condition, risk factors, and ways to improve your lifestyle;
  2. Supervised exercise sessions and education about how to self-manage your frequency, intensity, duration, and types of exercise after a heart attack; and
  3. Recommendations for exercise after you complete cardiac rehab and suggestions for ongoing follow-up care (how to prevent another heart attack).

Can I Exercise After A Heart Attack?

The short answer, generally speaking, is yes. 

A big YES. 

You CAN and SHOULD exercise to improve both your heart function and general health.

But before you exercise either in cardiac rehabilitation or on your own, you must be certain you receive clearance from your cardiologist and/or surgeon (if you’ve had cardiac surgery).

Depending on your condition, your doctor may want to perform a treadmill stress test on you just to be sure that your heart is stable enough to withstand regular exercise training (plus it gives you peace of mind too!).

How Soon Can I Exercise After a Heart Attack?

The time it takes to get back to exercise after a heart attack will vary from person to person, but you can generally get moving within a day or two after surgery.

While you’re in the hospital, the nurses will probably want to get you up on your feet and have you doing laps around the nurse station at a very low intensity (i.e., snail pace, just one foot in front of the other). 

You’ll likely do multiple bouts of, say, 5-10 minutes at a time.

Once you leave the hospital, you’ll probably be able to carry on with your low-intensity home exercise until your follow-up appointment with your cardiologist (or surgeon). 

This will likely be around 3-4 weeks or so.

You MUST remember that even when you start to feel better, there is still healing happening on the inside. 

A heart attack inflicts trauma on the heart and, if you’ve had any damage to the heart muscle, then your ability to exercise may be compromised.

Only your doctor can tell you the extent of heart damage (if any).

As mentioned above, cardiac rehabilitation sessions are also advisable, as this allows you to “test drive” your ticker under the watchful eye of a trained cardiac nurse and exercise physiologist.

Provided you are asymptomatic (no shortness of breath, no chest pain etc) and have no heart rate or rhythm abnormalities on the electrocardiogram, then you will likely be fine to get back to (or start) your exercise regimen.

What Are the Benefits of Exercise After a Heart Attack?

The benefits of exercise after a heart attack are not too different from those in people who’ve not had a heart attack. 

Though the main point of difference is a particular focus on improving the function of the heart, particularly if there was any damage to the heart muscle itself.

In other cases, some people experience what is known as “stunned myocardium” which is where the heart muscle is not dead, per se, but is injured and may regain some of its contractile properties after a few weeks.

Finally, it is possible to have a heart attack yet not have any damage to the heart muscle – often when treatment is administered soon after the onset of symptoms.

Reasons to Exercise After a Heart Attack

Improved Heart Function

Regular exercise training helps improve the heart muscle’s ability to use oxygen, resulting in less demand on the heart and a reduced likelihood of future symptoms of angina

Improved Body Function

This is a simplified way of saying that your exercising body becomes more efficient at extracting oxygen from the blood and using it down at the cellular level (i.e., in your exercising leg muscles). The benefit of this is that your heart doesn’t have to work as hard

Reduced Cardiac Risk Factors

Exercise can help reduce body fat, increase valuable muscle (increase your metabolic rate), reduce blood pressure, improve cholesterol and triglyceride levels, and reduce your risk of developing type 2 diabetes (or help improve your blood glucose control if you’ve already been diagnosed)

Reduced Risk of a Second Heart Attack

Following on from above, exercise can minimize your risk of having a second heart attack.  Life can be unpredictable sometimes and you never know when you’re going to have to exert yourself, so being physically trained is a great way to minimize the possibility of another heart attack

Improved Psychological Well-Being

Exercise has anti-depressant and anti-anxiety effects on the body.  It helps you burn off the daily stresses of modern living, and this is even more valuable after having had a heart attack

What’s the Best Exercise After a Heart Attack?

The best answer is: it depends.  On you.  

There’s no set in stone rule for which exercise is best after a heart attack, but walking and cycling are quite commonly recommended because they’re practical and easily accessible to most people.

For people that have had a stroke and may not be able to take up walking, arm-based exercises such as an arm ergometer (arm crank) can be a great way to get the heart rate up and challenge the heart to get stronger.

Weight training (resistance training) is also a viable form of exercise after a heart attack, but it is advisable to build a good cardiovascular exercise base first and then add the resistance training when you’re feeling stronger and have received clearance from your cardiologist.

How Hard Can I Exercise Immediately After a Heart Attack?

Inpatient Exercise 

The “by the book” exercise prescription for in-patient exercise (still in the hospital) as set forth by the American College of Sports Medicine is as follows, but I will also provide a bit of additional explanation.

Frequency

Early mobilisation

two to four times per day for the first three days of the hospital stay.

Later mobilisation

two times per day beginning on day four of the hospital stay with exercise bouts of increased duration.

While it’s true you need your rest, bed rest is also the single worst thing for your body. 

Remaining flat on your back in bed can cause stiffness, constipation, and lost of strength. 

The nurses will probably get you sitting up and walking around your hospital room just to place some gravitational load on your body.

Intensity

Suggested upper intensity limits:
Heart rate of 120 beats per minute or less; OR resting heart rate plus 20 beats per minute as the arbitrary upper limit.

Be aware that medications such as beta-blockers (i.e., metaprolol) will lower your heart rate so the numbers may not be an accurate indicator of how hard you’re working.

Even so, it’s still not a bad idea to keep tabs on your exercise heart rate so you know what your individual response is under the effects of your medication regime.

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).

Focus instead on a self-perceived intensity level of light to moderate exertion. If you find yourself short of breath, then cool your jets and  ease up a bit!

Time (Duration)

Perform short, intermittent exercise bouts of three to five minutes as tolerated. Incorporate a slower-level walk between bouts or rest if you feel this is necessary (go by how you’re feeling or your energy levels).

The general rule immediately after a heart attack is more exercise bouts per short duration, then ween yourself onto longer durations while reducing the number of exercise bouts until  you’re doing at least 30 continuous minutes of exercise at a light to moderate intensity (see above comments on intensity).

It is important to understand that these are general guidelines and may not be appropriate for you depending on the extent of damage from your heart attack (if any), medications, and other medical considerations. 

Discuss these recommendations with your nurse or cardiac rehabilitation team to find the right inpatient exercise prescription.

How Hard Can I Exercise Once Cleared By My Cardiologist?

Outpatient Exercise

The following post-heart attack exercise prescription is appropriate for when you’ve been re-evaluated by your cardiologist and/or surgeon and have been cleared for more vigorous exercise.

Frequency

Strive to perform at least four days per week and work up to daily (7 days per week).

Intensity

If you’ve had a follow-up treadmill stress test performed by your doctor then, depending on your level of conditioning, you might want to start off as low as 40% of your measured max heart rate up to as much as 80% of your heart rate.

This is casting a wide net, so it really will have to be tailored to your individual needs. 

As mentioned above, if you’re on beta-blocker medications, then your heart rate may not be an accurate reflection of your intensity.

Instead, aim for a self-perceived exertion in the window of “light to moderate to somewhat hard.”   

If you have the opportunity to exercise at a cardiac rehabilitation program, then you will likely receive specific guidance for monitoring your exercise intensity.

Bottom line:  take it easy at first and then gradually progress yourself to higher intensities, paying particular attention to the onset of any signs or symptoms (shortness of breath, dizziness, etc).

Time (Duration)

Give yourself a light 5 to 10 minute warm up consisting of light walking and stretching.   

Depending on your level of conditioning (or deconditioning), aim for 20 to 60 minutes.

The obvious implication here is shoot for the lower end when you’re just starting out and progress to 60 minutes as tolerated.

Increase your duration by around 10 to 20 percent per week, though this will have to be tailored to you depending on how fit or unfit you are.

Remember that exercise isn’t all just about your heart and lungs. 

Also pay attention to localized fatigue in your legs.  If your lower extremities experience fatigue, then just slow it down a bit or take a break.

You’ll find with regular training that you can go longer and longer each week throughout your recovery.

Type of Exercise

As mentioned above, walking and cycling are probably the two most common types of exercise due to their easy access. 

They engage the large muscles of the lower body which helps maximise the amount of energy (calories or kilojoules) you burn which in turn helps you lose weight and keep it off.   

Other forms of aerobic exercise may include:

  • Arm ergometer (arm crank)
  • Combined walking/cycling with the arm ergometer (combined upper/lower body workout)
  • Elliptical trainers
  • Rowing machine (rowing ergometer)
  • Stair climber machines
  • Aerobics classes such as step class or newer crazes like Zumba

The bottom line is find a form of exercise that you enjoy and are more likely to stick with.  

Find an exercise buddy and keep each other on the straight and narrow. 

For more information, see my post on “yo-yo exercise” and how to stay on track with your exercise regimen.

Can I Lift Weights (Resistance Training) After a Heart Attack?

You can perform resistance exercise after a heart attack, though I strongly advise you to first build a solid aerobic exercise foundation and get clearance from your cardiologist (particularly if you have high blood pressure).

Though not set in stone, our cardiac rehab team recommended approximately 6 to 8 weeks in cardiac rehab before we’d allow anyone to start lifting heavy weights. 

But for the most part, lighter weights may be a good idea just to help you learn the movement patterns and develop proper technique.

In the beginning, aim for at least two to three days per week lifting weights that permit around 12 to 15 repetitions, and performing 2-3 sets.

Be sure to EXHALE as you’re lifting the weight against gravity (remember: EXhale on the EXertion).  

Or when in doubt, do NOT hold your breath, as this may increase your blood pressure.

If you carry a lot of fat around your belly, some exercises might need to be modified if your midsection impedes your range of motion.

I would suggest working with your cardiac rehab exercise physiologist for specific guidance on resistance training.  While the benefits of weight training are clearly established, if not done properly it can lead to injury and possibly further cardiac complications.  

Alternatively, send me an email and I’ll do my best to steer you in the right direction.

Life Begins At 50 After a Heart Attack

I’m hopeful you were able to pick out a few bits of helpful information here, though I acknowledge that exercise after any cardiac condition can be a lofty topic with many subtleties.

The bottom line is that exercise after a heart attack is beneficial and advisable in STABLE individuals, but can be a health risk if you are not properly stratified and/or do too much, too hard, too soon after your event.  

The best advice is to work closely with your cardiologist and cardiac rehab team for guidance specific to your condition.

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Bill

Tuesday 13th of October 2020

Hi, I am a 69 year old male. Never smoked. Avid lifetime runner with approximately 50,000 miles of running under my belt. I had a heart attack two years ago (two 99% blockages of the LAD. Had two overlapping stents of blocked areas.). I’m bike riding now and usually ride 20-30 miles per ride three times a week and average 78% of the age calculated MaxHR for a 65 year old or, specifically, averaging 122 BPM for 1 hour and 45 minutes to 2 hours and thirty minutes. I want to push harder. Am I doing too much? Cardiologist says to do what I want with out restrictions.

Dr Bill Sukala

Monday 23rd of November 2020

Hi Bill Thanks for your comment. It's hard to say what's necessarily "too much" because it really depends on the individual. To your credit, being an athlete your entire life and being more in tune with your body, you'll have a better gauge on your exertion level, as opposed to someone who's been relatively inactive their entire lives.

The most important thing is that you are not having any signs or symptoms while exercising. If you are able to sustain your target heart rate over the course of 20 to 30 miles, then I'd say that doesn't sound like an unreasonable heart rate.

Also important is that your cardiologist has given you clearance to exercise (assuming everything is working well and there are no hidden surprises). Usually during an angiogram, the doctor will have a look at other arteries to get a gauge on things. So assuming your other arteries are clear and you are NOT symptomatic in any way then, realistically, you'll more than likely be fine.

In order to work to the higher workloads, just be careful and try to systematically push up your intensity in tiny increments. This will allow your body to adapt naturally and also remove the risk of really going all-out, full-throttle. Provided you're increasing your workload slowly and gradually over time, you are minimising your risk.

Hope this helps.

Kind regards, Bill

Dain

Tuesday 22nd of September 2020

Hi Dr. Sukala, Just a quick question for you. I realize you probably get a lot of messages so thank you for your time. I am 39yrs old, competitive bodybuilder who had a heart attack from a fully blocked Right Coronary Artery. Diagnosed with moderate left ventricular hypertrophy. Put on Plavix, Lisinopril, Metoprolol, aspirin, Atorvostatin. Energy-wise I felt fine/normal two days after the stent. I waited two weeks to go back to gym. Started with 15min steady walk pace. Some light ab work and started very light weights. After few sets of 15-20 reps very slow, I only noticed a very slight cramp feeling in lower chest when taking deep breath. This feeling went away after few minutes and not present with normal breathing. Same feeling one would get if running hard. My heart rate was still lower than 100. Is this expected? Did i go harder than I was ready for? Due to insurance complications, I wont see my cardiologist for two more weeks so looking for your thoughts. Thank you again! I do appreciate it.

Dr Bill Sukala

Tuesday 22nd of September 2020

Hi Dain, Thanks for your comment. A few things to consider here. If you're a bodybuilder, it's not uncommon to have a bit of left ventricular hypertrophy. Did your doctor confirm this was due to the exercise? Or from any other pathology?

Also, was there any indication from tests that you had any damage to your heart muscle? If there is any damage to the myocardium itself, that can potentially require a bit more healing time.

In many cases, an angioplasty with stent only requires a couple days in the hospital, but full healing time can extend out to at least a month or so. In other words, even if you're feeling good (which is a sign the stent is working), it's important to remember that there IS still healing happening on the inside.

It's hard to say exactly why you experienced the cramp, but I have heard of quirky things like this in some people after angioplasty and stent. But the thing to ask is, was it a cause and effect thing (meaning, did the angioplasty/stent cause the cramp) OR was it just a coincidence of two things happening at the same time but one did not cause the other (meaning, you had a cramp from exercise, but it just so happened to occur after you had an angioplasty / stent procedure)? These are the things that you'll want to discuss with your doctor.

While you're in the initial recovery phase, there is nothing wrong with laying low for the first month. Yes, you can still do low level exercise as long as you're paying attention and monitoring yourself for any signs or symptoms (chest pain, shortness of breath, all the usual suspects).

Usually, a month after your procedure, you'll have a follow up appointment with your cardiologist. Just be sure to mention these things and discuss your concerns. I can certainly appreciate that being an active individual, this sort of thing is even more psychologically worse than for someone who is a life-long couch potato. In other words, it's a quality of life sort of thing, so be sure ask all your questions at the appointment, as your doc will be most familiar with your medical history. You should also ask if there is a practice nurse on duty at the cardiologist's office that could be available to take your phone call if you should have any further issues. This way you don't necessarily need to go through the hassle with insurance to get another appointment sorted out. I worked in the healthcare system in California and had to fight insurance companies nearly every day, so I can really empathise with your frustration.

Hope this information helps point you in the right direction.

Kind regards, Bill

Pete

Monday 13th of July 2020

Hi Dr Sukala,

Thank you very much for your reply, it was very much appreciated.

Best wishes and thank you again,

Pete.

Peter

Tuesday 7th of July 2020

Hi Dr Sukala, I had a heart attack in 2016 aged 49, and had one stent fitted. While I was in hospital I found out my mother was diagnosed with breast cancer and on New Year’s Day 2017 she passed away. Having lost both of my parents close together I suffered from depression and anxiety, have led a pretty sedentary lifestyle. My mental health is much better now, but now I’m concerned about getting back into exercise after so long. Do you have any suggestions or tips for starting again? I really don’t want another heart attack.

Thank you Dr Sukala,

Pete.

Dr Bill Sukala

Thursday 9th of July 2020

Hi Pete, Thanks for your message. I'm very sorry to hear about losing your parents and having to go through all that with your own heart. Getting back into exercise will, of course, help you physically, but it will also help your mental health as well.

The first and most important thing is making sure that your heart is stable. I'd recommend speaking to your cardiologist during your next check up and ask if there are any specific precautions relative to your medical history that could possibly cause any problems with exercise. Chances are, you'll be ok. You might even request a stress test which will allow the doctor to see that your heart is working normally at rest, during exercise, and after exercise (i.e., normal heart rate, rhythm, blood pressure, nothing abnormal that could pose a risk). Assuming that's all normal, then realistically, you should be able to get into exercise without any issues.

While it's true that you had a heart attack and stent placed, it's also true that you're still a human being and your body works the same as anyone else's. As a general rule, just be sure to ease into it and not try to take on too much too soon (i.e., super heavy, high intensity lifting on day one).

You might consider hiring an exercise physiologist in your area that has experience working with people who've had a cardiac intervention. This will probably help put your mind at ease and facilitate a safe progression.

Hope this helps.

Kind regards, Bill

Glenn

Thursday 15th of August 2019

Hi Bill. Thanks for the reply. I took your advice regarding medications limiting heart rates and backed off. Moderating my exercise helped a lot. My stamina increased significantly and I was able to increase my intensity somewhat. Its been > year since my MI and I've worked with my cardiologist and am only taking Zetia and Atorvastin. I didn't have high blood pressure before and don't have it now that I'm off Coreg. The fatigue is gone and no chest pain or shortness of breath caused by Brilinta. LVEF is now around 55. My heart rate increases more when I hike, exercise, lift weights, etc. Coreg had kept it at 120 to 135 and I can easily go up to 150 bpm when I'm hiking a mountain. I have an Apple watch for the express purpose of monitoring my heart rate. This allows me to increase exercise intensity more but I'm not sure where I should limit my heart rate. Are there general guidelines that have been established to calculate heart rate limits after a heart attack? The rates they established during rehab are really low intensity and don't seem meet my needs for exercise.

I really appreciate your help. Reading your articles and responses to my and others comments helped out a lot

Thank again, Glenn

Dr Bill Sukala

Thursday 15th of August 2019

G'day Glenn, Thanks for taking the time to stop back and leave a follow-up comment. Nice to have some feedback.

In the immediate post-heart attack phase, yes, the heart rate guidelines are quite conservative as follows:

Post-MI: Maintain heart rate (Hr) less than 120 beats/min or heart rate at rest + 20 beats/min

However, once you've been through the initial cardiac rehab and assuming you are medically stable and cleared for higher intensities by your doctor, then you probably won't have too much to worry about. As I may have said in a previous response, for those who are quite active, I often recommend asking your doc if you can have a treadmill stress test performed to see how your heart goes at high workloads. If you have a normal rise in heart rate and blood pressure, no cardiac arrhythmias, and no signs or symptoms (other than the expected fatigue and shortness of breath due to the high intensity), then your doc may tell you that it's safe to get back to working out hard again.

The most prudent course of action is always the same: maintain good communication with your doc and discuss the risks vs benefits of higher intensities.

Hope this helps.

Cheers Bill