At last……. an exercise study on normal weight diabetics!

Yes, most exercise studies on diabetics are on the overweight or obese diabetics with the recommendation to do 3–5 days per week of aerobic activity at moderate to vigorous intensity, achieving a minimal exercise duration of 150 min per week, and two to three sessions per week of strength training.

However, worldwide about 20% of diabetics are of normal weight (Body mass index <25 Kg/m²) and more so in India.

Not only that but compared with overweight/obese subgroups, people with a normal weight at diagnosis of type 2 diabetes are shown to have a higher risk of mortality. Thirdly, normal-weight type 2 diabetes is associated with sarcopenia or loss of muscle mass which mediates the elevated mortality risk in people with normal-weight diabetes compared with overweight people with type 2 diabetes.

So what exercise advice to give in such diabetics of normal to low weight?

In a study published in July 23 issue of the journal Diabetologia (STRONG-D study), 186 normal weight type 2 diabetics who did strength training exercises only, decreased their HbA1C levels significantly more than those doing aerobic exercise alone or a combination of aerobic and strength training.

Also, their muscle mass improved much more than the groups doing aerobic or combined exercises, which correlated with the decrease in HbA1C.

The moral of the story is that if you are a lean diabetic, concentrate on strength training with an aim to improve your muscle mass.

 

 

Doc, how to know if I already have ‘silent’ blockages in my coronary arteries?

This is a reasonable and commonly asked question, because some of us may have 'silent' coronary disease without any symptoms and if we know it, we can take steps to prevent future catastrophe.

Recently a 62-year-old gentleman died in his sleep without any symptoms. Could he have had silent coronary disease? If yes, how could it have been diagnosed while he was alive?

A recent research found that some degree of coronary artery disease is prevalent in almost 50% of people over the age of 45.

At present the commonest way to diagnose coronary artery disease accurately is with catheter angiography performed in the hospital. But performing angiography on every human without symptoms of heart disease is expensive, not harmless and inappropriate.

Another type of angiography which does not need hospitalization is CT angiography, which can be used to diagnose coronary artery disease. But it has the disadvantage of exposure to radiation and the possible adverse reaction to the intravenous liquid (contrast) injected. Hence, the test is currently only advised in people with symptoms of heart disease and is not recommended in people without any symptoms. However, in the near future when machines that emit less radiation become available, this test may become more widely used, especially since, as noted above, about 50% of people may have small or large blockages in the arteries of the heart.

One of the disadvantages of these tests in an asymptomatic person is that if an abnormality is detected, then it may lead to a procedure which may (with exceptions) be unnecessary. So that has to be guarded against.

A third way to detect heart disease is finding the coronary calcium score- a simple CT scan that measures how much calcium is in the arteries of the heart. This is useful for people over the age of 40 and those with high cholesterol, or those with risk factors, especially when it comes to decision making about taking drugs like statins. Calcium gets deposited in the arteries only when they are diseased. So arterial calcium is a sign of its disease.

A fourth way to detect heart disease is the treadmill stress test. In people without symptoms it has the disadvantage of being falsely positive (abnormal test result without disease) or falsely negative (normal test result despite underlying disease) in some people.

So, for people without symptoms the test is recommended in only for some, such as those over 40 or those with risk factors such as diabetes who have been sedentary until now and who now want to start regular and intensive exercise, or whose occupation involves responsibility of many people, such as airplane pilots, air traffic controllers, etc. People who are at intermediate risk due to presence of risk factors and those who have to undergo any surgery can also have this test done. One advantage of this test is that it can measure your work capacity (cardiovascular fitness) which is related to future heart attacks.

The fifth method is an electrocardiogram (ECG) and echocardiogram. These tests determine whether a person has had an attack in the past or not. Coronary blockages are not detected by these tests if there  are no active symptoms or thyere has been no heart attack (or damage to the heart) in the past.

The sixth method is to measure the blood pressure of the arms and legs. If the leg pressure is equal to or less than the arm pressure, it is a sign of leg artery disease which may be accompanied by coronary artery disease. If there is a difference of more than 20 in the left and right arm pressure, it is a sign of arterial disease in the arm and the possibility of coronary artery disease increases in such people.

The seventh method is to measure all the risk factors and determine the chance of having a heart attack in the next 10 years through some formulae called risk scores. Obviously this can only give an estimate, not absolute prediction. Risk scores such as ASCVD risk score or JBS3 risk score can be found on the net.

The eighth way is to do doppler test of one’s carotid (neck) and femoral (thigh) arteries to check for fatty deposits. People with fatty deposits in these arteries are more likely to have the same in coronary arteries too.  

So, to tell whether you have a blockage or an obstruction in the coronary artery or not, one has to select a test (or combination of tests) most appropriate to your condition and decide.

But your lifestyle is more important than knowing whether you have undiagnosed arterial disease or not. This is because despite having the disease, if the lifestyle is good, the future is good, and conversely,  if there is no disease, but the lifestyle is bad, the disease may still occur. Of course, if any abnormality is found in these tests, there is an opportunity and motivation to improve lifestyle and start preventive medication like statins and aspirin under medical guidance.

-          Dr Akshay Mehta

 

Medications to prevent coronary heart disease

Medications: The third step in preventing coronary heart disease

The first two steps we can take to prevent heart disease are some tests and a few lifestyle changes, which was discussed elsewhere. For many people, taking certain medications under a doctor's supervision to prevent heart disease is necessary and very beneficial. It can be called the third step to prevent heart attack.

The two main groups of drugs used to prevent heart disease are 1. Cholesterol lowering drugs like statins and 2. “blood thinners” like aspirin.

For people who are known to have coronary heart disease, for example for people having angina or who have had heart attack, angioplasty  or bypass surgery, or brain stroke or disease in the arteries of the legs, both the above kinds of medicines are important and advisable for lifelong use under medical supervision. This is so that the chances of progression of disease or recurrence of untoward events like heart attack are minimized.

Those who have no symptoms of the disease but have a high coronary artery calcium score (done due to any reason) or if the heart arteries appear diseased in CT coronary angiography (again, done for any reason), it is better to take these two drugs as per the doctor's advice.

Statins not only lower LDL cholesterol in the blood but also stabilize or ‘shrink’ the fatty deposit in the arteries, preventing their erosion or rupture which can lead to a heart attack.

Other drugs which may be advised in addition to or instead of statins are ezetimibe, bempedoic acid, PCSK9 inhibitors, fibrates and ecosapent ethyl, which reduce cholesterol and triglycerides.

Drugs like low dose aspirin prevent clumping of platelets and clotting which can occlude arteries leading to a heart attack. Other “blood thinners” which may be advised in addition to or instead of aspirin are clopidogrel, ticagrelor and prasugrel.

What about people who have not had any sign of heart disease and are apparently healthy? Should they be taking these preventive drugs?

Well, statins may also be necessary for those who have no symptoms of heart disease, but who are at high risk of developing heart disease in the future.

So how do you know in seemingly healthy people who are more likely to develop heart disease in the future?

The likelihood of future heart disease in apparently healthy people depends on their risk factors and certain physical conditions. Doctors take these two factors into consideration or use certain formulas (risk scores) to predict how likely people are to have a heart attack in the next 10 years. All risk scores (Google ‘CVD risk stratification in Indians’) are estimated on the basis of how many and how severe the risk factors are in us. As mentioned earlier the known factors are hypertension, diabetes, cholesterol, smoking, obesity, lifestyle, improper diet, family history of heart disease etc.

If the chance is more than 20% according to the risk scores, or if if LDL cholesterol is over 190 mg% or if there is long standing diabetes, then taking a statin (of course, in addition to healthy lifestyle choices) may have more benefits than risks.

If the likelihood of having heart disease on the basis of risk scores is less than 5%, then only lifestyle changes may suffice to prevent the disease.

If the chance is between 5% and 20%, the decision to take the drug requires further tests, such as coronary artery calcium score, doppler test of femoral and carotid arteries, BP difference between all 4 limbs and blood tests like apoB, hs CRP, LPA, troponin, etc. Other physical conditions like lung or joint disease, kidney disease, HIV, high blood pressure, diabetes during pregnancy in women or a history of premature birth or lack of breast feeding may put one at higher risk so that it may be beneficial in these people also to take a statin under medical guidance.

The decision to start a statin should be based on discussion with the doctor and after understanding its benefits versus harm for the individual.

Other ‘preventive’ drugs are all medications to keep blood pressure and sugar under control. Of particular preventive benefits are certain medications such as SGLT2 inhibitors and GLP1 agonists for diabetes, RAAS blockers for hypertension, beta blockers for hypertension with angina, or after a heart attack or heart failure.

Should seemingly healthy people take aspirin for life to prevent heart attacks?

It was a popular belief that everyone should take baby aspirin to prevent heart attacks because heart attacks are caused by blood clots in addition to fatty deposits and aspirin prevents these clots from forming. But after a few years of research on many people, it was found that along with the benefits of aspirin, there is also adverse effect of bleeding. In people who have a history of bleeding or are over 70 years of age, the risk of bleeding outweighs the benefits of preventing heart attacks, so the net harm is greater. So, taking aspirin over the counter or without medical advice is inappropriate for such people. Yes, it can be taken to prevent heart attacks (not to prevent death) in people younger than 70 with risk factors for heart disease or with long-standing diabetes, but after consulting a cardiologist.

Thus, almost 90% of heart attacks can be avoided by 3 steps: 1. certain tests, 2. certain lifestyle changes and 3. taking certain medications as advised by the doctor. Despite all these efforts, if a heart attack (the remaining 10%) still occurs, the damage caused by the heart attack can be avoided by immediately recognizing the symptoms and getting prompt treatment.

 

 

 

Purpose, Sleep and Walking Speed- A Holy Nexus.

Purpose, Sleep and Walking Speed- A Holy Nexus.

A sense of purpose in life is known to confer health benefits through multiple mechanisms which mainly relate to the mind.

However, two recent studies show that having a purpose or a project affects health through 2 important parameters that affect health.

One is better sleep. Yes, being on purpose through the day promotes better sleep at night. That was the result of a study reported in the July 9, 2017 issue of the peer reviewed journal ‘Sleep Science and Practice’ on about 800 people with an average age of 80 years and showed that having a purpose in life specifically results in fewer sleep disturbances and improved sleep quality and over a long period of time.

Having a life purpose also improves another factor that impacts our sleep, health and longevity.

It is our walking speed.

Do people with a sense of purpose walk faster? (Remember Gandhiji walking for the Dandi march!)

A recent article published online in the August 16, 2017 issue of JAMA Psychiatry (which is the stimulus for this write up) reports a study on 4486 persons with average age 63 years. It found that people with a sense of purpose in life (measured by Purpose of Life subscale of the Ryff Psychological Well-Being scales) have less diminution in their walking speed with aging as people low on life purpose.

This has important health connotation because walking speed is inversely related to frailty and directly proportional to good health and longevity. Also, better walking means better sleep, usually.

Of course there are other factors too, impacting sleep and walking speed

But having an exciting reason to get out of bed in the morning does put a pep into your step and depth into your sleep- two important factors impacting your health.

Cholesterol conundrum

36. The Cholesterol Confusion !

Although we doctors advise people to get their cholesterol (especially LDL cholesterol and other  lipids) checked and keep it under control with diet and exercise, and also sometimes advise to take drugs like statins in addition, the “cholesterol theory” has come under fire in a lot of scientific and social media.

The issues which have raised a controversy are :

1. Is “cholesterol in food” harmful ? Does it raise cholesterol level in blood? Should it’s intake be restricted?
2. Is high intake of “fats in food” harmful ?
3. Is “high cholesterol in blood” the cause of atherosclerosis, leading to coronary heart disease ?
4. Are statins good medicine?

As an answer to the first question, a message on social media says :

“Cholesterol is finally officially removed from Naughty List. The US government has finally accepted that cholesterol is not a nutrient of concern doing a U-turn on their warnings to us to stay away from high-cholesterol foods since the 1970s to avoid heart disease and clogged arteries.
This means eggs, butter, full-fat dairy products, nuts, coconut oil and meat have now been classified as *safe* and have been officially removed from the nutrients of concern list.”

This is a dangerous half truth which needs to be addressed and clarified.

Yes, the first part of the message is true; 300gm per day limit on dietary cholesterol is relaxed by the2015-2020 US guidelines. But this is nothing new or extra-ordinary, because dietary cholesterol- that is raw cholesterol that is present in foods like egg yolk, does not contribute much to raise blood cholesterol in the quantity consumed (for example each egg yolk has 186 mg of cholesterol). It is the saturated and trans-fats in food which really contribute to raising blood cholesterol. 

Hence, the error is in the second part which lists butter, full-fat dairy products, and meat as *safe* and have been officially removed from the nutrients of concern list.

Nothing can be farther from the truth. These foods  have NOT “been officially removed from the nutrients of concern list” as the message falsely proclaims.

This is because, butter, full-fat dairy products, and meat contain large amounts of saturated fats, besides containing cholesterol, and as said earlier, it is the saturated and trans-fats in food which really contribute to raising blood cholesterol. 

The US guidelines can be seen from: http://health.gov/news/dietary-guidelines-digital-press-kit/2016/01/top-10-things-you-need-to-know/

The relevant sections reproduced verbatim, say the following:

5.      Healthy eating patterns limit added sugars. Less than 10% of your daily calories should come from added sugars. ChooseMyPlate.gov provides more information about added sugars, which are sugars and syrups that are added to foods or beverages when they are processed or prepared. This does not include naturally occurring sugars such as those consumed as part of milk and fruits.

6.      Healthy eating patterns limit saturated and trans fats. Less than 10% of your daily calories should come from saturated fats. Foods that are high in saturated fat include butter, whole milk, meats that are not labeled as lean, and tropical oils such as coconut and palm oil. Saturated fats should be replaced with unsaturated fats, such as canola or olive oil

The confusion and error stems from mixing up foods like eggs containing ONLY cholesterol with foods like butter, full-fat dairy products, and meat which have saturated fat and trans-fat, AND cholesterol in them.

So one must distinguish between foods containing ONLY cholesterol, like eggs and seafood (like shrimp and lobster) and foods containing BOTH cholesterol and saturated fats & trans fats like butter, full-fat dairy products and meat. They cannot be put in the same basket.

While the former can be had in moderate amounts, the recommendation for saturated fats is not more than 10% of total calories, and trans fats - as low as possible. And yes, sugar should be restricted.

Coming to the question number 2:

About the advice on fats, both, the proponents and opponents have strong arguments supporting their views.

Contrary to recommendation from AHA mentioned above, recent studies like PURE study show that saturated fats are good for us. However, there are many flaws in the PURE study.

Anyway, in the light of conflicting opinions on this, what a patient recently told me was revealing. (One always learns from patients).

He was a 102 Kg American with symptoms of angina due to coronary artery disease. He said that when his meal had meat, pork, cheese or butter, slightest exertion after the meal caused chest discomfort, whereas when he ate a Mediterranean like diet (fruits, salads, fish, nuts whole grains etc) he could walk a mile without chest discomfort.

Saturated fats (like in cheese, meat etc) are known to increase the thrombogenicity (tendency to clot) of blood and inability of coronary arteries to relax (endothelial dysfunction).

This was a direct evidence of the harmful effects of diet high in saturated fats in a patient with coronary disease.

Hence large consumption of bad quality fats (meats, cheese, butter, chicken or fried food etc) is not a good idea especially if you are above 30 or already have coronary artery disease or risk factors like abdominal obesity, physical inactivity, hypertension, diabetes, abnormal lipids (cholesterol), smoking, family history of coronary heart disease, etc. whereas consumption of moderate amounts of good quality fats (olive oil, fish, nuts) would be ok.

Trans fats are the worst and should be minimum in diet.

Coming to the question number 3:

 Is high cholesterol in blood the cause of atherosclerosis, leading to coronary heart disease ?

1. Well, firstly, cholesterol is needed by the body. It is an essential component of cell membranes and a precursor of bile acids and steroid hormones. Cholesterol is also vital for neurological function. Most of our body’s cholesterol is made in the liver. The rest is obtained from foods –especially those that are high in saturated and trans fats. That’s a problem because these fats can cause our liver to make more cholesterol than it otherwise would. For some people, this added production means they go from a normal cholesterol level to one that’s unhealthy.

So although cholesterol is required by the body and is mostly produced in the liver, our dietary and physical activity habits alter the levels of not only cholesterol but other circulating fats in the blood to pose risk.

2. Secondly, the most clear cut and direct proof that too much cholesterol can cause heart disease is in people with genetic or inherited high low density lipoprotein cholesterol (LDLC) (above 190 mg %).  YES, in such people cholesterol is a direct and main CAUSE of atherosclerosis leading to coronary disease.

3. Thirdly, for most other people, cholesterol, especially LDL cholesterol is a risk factor, a strong risk factor.

A risk factor is an abnormality which is strongly associated with a disease, but for which an exact cause and effect relationship is not established.

In most people, atherosclerosis is a disease of multiple factors in which cholesterol is a team player, a very important one. It is one of the risk factors like hypertension, diabetes, smoking, physical inactivity, central obesity, unhealthy diet, etc which singly or in combination increase one’s chances of having atherosclerotic coronary artery disease (CAD). The more the number of risk factors, the more abnormal each one of them is and the longer it remains untreated, the greater the likelihood of having the disease.

Different set of risk factors operate in different people. In some patients, high cholesterol alone may indeed be the dominant cause; for example people with genetically very high cholesterol levels; in others, hypertension is the dominant cause, for example in the Japanese; in still others, cigarette smoking may be the dominant cause.  But in most people multiple factors act synergistically to cause CAD.

4. Fourthly, although we do not know the exact cause of atherosclerotic disease in every one, we know the 2 key events that lead to the disease.

a. Inflammation of the arteries, especially its inner lining making it “sticky” to ‘mop up’ circulating lipoproteins.

b. Accumulation of these cholesterol-rich lipoproteins within the arterial lining at certain sites.

5. So, the fundamental cause of atherosclerosis is injury and inflammation of the inner lining of arteries (making it sticky) due to above mentioned risk factors and ingress of cholesterol containing lipoproteins into this lining creating more inflammation and atherosclerosis

6. Even if we assume that cholesterol is not the cause of atherosclerotic disease, studies done on more than 2 million people with over 20 million person-years of follow-up and over 150 000 cardiovascular events demonstrate a remarkably consistent log-linear association between the amount of LDL-C  in the blood along with the duration for which the body is exposed to it and the risk of atherosclerotic disease like CAD.

Not only that, but also that reducing or correcting it (whether by lifestyle changes or statins) reduces the chances of disease, whatever the initial cholesterol levels. These measures not only reduce cholesterol levels in the blood but also cause the fatty deposits in arteries to stabilize and even regress, which can REVERSE CORONARY DISEASE.

Relatively modest 17% drop in cholesterol level could lead to a 40% decrease in coronary death rate for men with cholesterol levels initially in the range of 221-244 mg% !

7. The final arbitrator is what we see in our patients. Surely, we see in our day to day practice the tremendous benefit  of life style and statins stabilizing and regressing the disease.

But what about the study published in the British Medical Journal recently and displayed all over the media,  (BMJ Open 12 June 2016. Volume 6, Issue 6), concluding that there was a lack of an association or an inverse association between low-density-lipoprotein cholesterol (LDLC) and mortality in the elderly (above 60). 

This study has many flaws, such as the following :

•          There is the possibility that many studies may have been missed out from this paper. The review searched only a single literature database, excluded studies available in non-English language, and excluded studies where the title and abstract did not appear to contain information on the link between LDL and mortality in older adults.

•          The study only looked at the link in older adults aged over 60, whereas LDL-cholesterol levels may show stronger linkage with long-term mortality in younger adults.

•          There were varying degrees of interfering (‘confounding’)  factors that could be having an influence on the link between LDL and mortality, such as smoking, alcohol, socioeconomic factors, presence of conditions, and use of medications which were not incorporated into the studies.

•          Only LDL cholesterol was examined. As written below, there are other lipid parameters which play a part in people with apparently “normal” LDL levels.

•          The endpoint of the review is all-cause mortality – not cardiovascular mortality with which high LDL-cholesterol has stronger links.

•          Most important is there is no detail on the use of statins in this population. It may be possible that people found to have the highest LDL cholesterol levels at the study's start may have then been started on statins, and this could have dramatically cut their mortality risk.

•          Finally, this could well be a preconceived view of the authors regarding the role of cholesterol, given that 4 of the study authors have previously written book(s) criticizing "the cholesterol hypothesis", and that nine of the authors are members of THINCS – The International Network of Cholesterol Skeptics !

Ok, but we find some people with “low cholesterol” have heart disease and some with “high cholesterol” don’t have disease. Why ?

This is because of multiple reasons listed below:

1. Other risk factors (like smoking in the young, or hypertension, diabetes, central obesity, life style etc) impacting the effect of cholesterol, may play a predominant role in some people.
2. The NUMBER of LDL particles is more important than the AMOUNT of cholesterol in them:

Cholesterol is predominantly carried in the blood in particles called LDL particles. Each LDL  particle carries a certain amount of cholesterol. The amount of cholesterol carried by LDL particle varies between individuals and in the same individual at varying times. It is the number of these particles and not absolute amount of cholesterol that is best related to atherosclerosis.

Usually, they match. That is, the amount of cholesterol correlates with the number of particles circulating in blood.

Hence instead of estimating the number of particles (which is a tedious and expensive measurement to do in practice) we measure the cholesterol in blood, which is more easily done in our lipid tests.

However, in some people the two may not correlate.

For example two persons with same amount of cholesterol may have it carried by different kinds of particles. (See figure) In one (A), cholesterol is predominantly carried by a small number of large sized  particles. In person B, it is carried by small sized particles which are large in number to carry the same amount of cholesterol.

The latter, also called small dense LDL particles are more atherogenic both because of the number and the small size (besides other factors). The former are less atherogenic due to the small number, though the amount of cholesterol is the same.

Hence two persons with same amount of cholesterol can have different propensities to develop coronary disease due to difference in the number of LDL particles.

Hence a person with high cholesterol may escape from disease (due to small number of large sized particles) and a person with low cholesterol may suffer because of large number of small sized particles.

3. Other Lipoprotein  particles : Although as we said earlier, LDL carries about 90% of cholesterol in blood, in some people, other lipoproteins may carry significant amount of cholesterol, such as Lp(a), Intermediate and very low density lipoproteins (IDL,VLDL etc). Thus although the LDLC or number of LDL particles may be average or ‘normal’, the TOTAL number of lipoprotein (LP) particles may be high, causing the disease. This is best known by the amount of apoB in blood, because each LP particle is tagged with one apoB.
4. HDL cholesterol : Recent studies have found that the quality of HDLC and the number of HDL particles may be protective against atherosclerosis. In other words, low HDL efflux capacity or low HDL particle number could be the risk factors in some people.

In practice, since LDL cholesterol can be easily measured, since it correlates with particle number in most people, is seen to be associated with heart disease in a vast majority of population and since particle number cannot be easily measured, it is most commonly utilized as a risk factor and a target for treatment.

However the amount or mass of cholesterol or its level in blood may not correspond with the  number of particles in all as seen above. Also, as seen above, other factors may impact its effect.

That is why studies done on cholesterol as a risk or causative factor for heart disease may show contrasting results and hence the controversy over “the cholesterol hypothesis”. 

Hence, although cholesterol, especially LDLC is a causative factor in most people, in some it may be the number of particles or other lipid abnormalities or risk factors that may be playing a role.

In them, just knowing LDLC may not be enough and tests like apoB (which gives an idea about TOTAL number of LP particles) or non HDLC or Lp(a), or HDL particle number and efflux capacity etc may be required.

Figure : Patient A (left panel) with predominance of large sized LDL particles and Patient B (right panel) with predominance of small sized LDL particles. Although the total cholesterol CONTENT in both is the same, patient B has more NUMBER of particles putting him at higher risk although the cholesterol level in blood is same as patient A.

Finally, question number 4 : Are statins good medicine?

The answer in one line is for prevention of coronary heart disease, nothing in the history of medicine has ever been shown it more convincingly.

More on statins in another chapter.

Thus, the cholesterol story is neither a simple yes or a simple no. One should understand its intricacies and ramifications. It is definitely not a ‘scam’, but a continuing saga of human endeavor in pursuit of solving the mystery that is atherosclerotic coronary heart disease.

How to have a safe marathon:heart- wise?

How to have a safe marathon: heart- wise?

It is common knowledge that physical exercise promotes health and prevents heart disease and heart attacks. However, we also sometimes see young, healthy looking people having heart attacks or dying suddenly during training or during marathon running.

Why is this paradox? And what can we do about it?

Well, the difference is between moderate regular exercise which has all the benefits of exercise minus its risks, versus intense, vigorous exercise, which has slight additional benefit but with increased risk, especially if unaccustomed.

The risk of vigorous exercise like running or training for a marathon comes from interplay of two factors:

1.       Underlying heart disease (most commonly fatty plaques in coronary arteries) which may or may not be detected by routine tests such as blood tests, ECG, or a stress test.

2.       Surge of chemicals like adrenaline and increased shear stress on coronary arteries which may cause rupture of these fatty deposits (plaques) as well as disturbance in heart rhythm.  Also, with vigorous exercise, especially if unaccustomed there is ACTIVATION OF A TYPE OF BLOOD CELLS CALLED PLATELETS. When activated, these can clump together and initiate clot formation at the site of the ruptured plaque in the coronary artery. This clot along with the fatty deposit and with possible spasm of the artery can suddenly block the blood flow in the coronary artery which leads to heart attack or sudden death.

(A third factor recently found in marathon runners has nothing to do with heart disease, but with excessive heat and dehydration causing heat stroke).

Hence, to prevent a cardiac catastrophe on vigorous exercise we need to do the following:

1. If you are above 30 years of age or younger than that but with risk factors such as smoking, hypertension, diabetes, lipid (cholesterol) abnormalities, or have a family member who has had heart disease, or have unhealthy lifestyle (frequent and regular intake of sugar, trans- fats or processed very high fat food and total lack of physical activity) and mental stress, you should undergo PROPER CHECK UP BEFORE JOINING the exercise program. This consists of clinical examination by a cardiologist, ECG, blood tests and a treadmill stress test. Even while you are regular on an exercise program, it is advisable to undergo these checkups once a year if you are above 30 years of age or have one or more of the risk factors listed above.
2. In many people, these routine tests do not reveal an underlying abnormality, despite having fatty plaques and being susceptible to heart attacks during vigorous exercise. Hence additional tests such as a coronary artery calcium score (CACS) may be advisable. CACS is a ‘score’ which tells the amount of calcium in one’s coronary arteries and a direct evidence of amount of calcified fatty plaques . Higher the number of these plaques (CAC score) higher the severity of coronary disease and chances of a cardiac event in future, whereas a score of zero implies absence of calcium containing plaques (doesn’t rule out soft plaques) . CACS does not require injection of any liquid but has the disadvantages of cost as well as slight but definite exposure to radiation (equivalent to about 10 chest X rays) which could be ‘potentially’ carcinogenic.

A still better test to reveal all kinds of fatty plaques in the coronary arteries is a CT coronary angiogram which has still higher risk of radiation (equivalent to about 30 to 60 chest xrays) and potential effect on the kidneys due to the liquid contrast injected. 

It should be clearly understood that both these above mentioned tests are as yet not recommended as mandatory or routine in people without symptoms before joining a vigorous exercise program.

However, looking at the higher incidence of heart attacks in young Indians (3 to 4 times that in westerners), and inability of routine tests like an ECG or a stress test to pick up disease in many,  these tests may be worth a consideration- but only after talking to one’s cardiologist, and after fully understanding the risks versus benefits of such tests.

3. A 2 D Echo is advisable in people who have had heart attacks, angioplasty or bypass surgery in the past or have some abnormality detected during clinical examination by the doctor or an abnormal ECG. 2 D Echo is a safe procedure for everyone but adds to the cost. It can reveal structural or functional abnormalities of the heart which may not be picked up on routine clinical exam. It does not  reveal the state of coronary arteries.

4.       Proper control of risk factors like hypertension, diabetes and abnormal cholesterol with healthy lifestyle and addition of medications if required.

5.       Use of preventive medications such as statins and low dose aspirin, on the basis of your risk defined by clinical evaluation, routine tests and your coronary artery calcium score (if done) and after medical consultation. Statins have been proven to shrink and stabilize fatty plaques and prevent them from rupture. Aspirin prevents clumping of platelets.  Extension of same benefits during vigorous exercise may prevent a heart attack.

6. Starting slow -when starting afresh. For initial week or so exercise at very low intensity and pick up in intensity and duration after a few weeks of lighter exercise. Same precautions should be observed when RESTARTING after a break of more than a week. Warming up and cooling down at every session, each for about 5 to 10 minutes.
7. BEING REGULAR. Out of all the characteristics of an exercise program, this is the most important. Regular means at least five times a week, round the year. IF THERE IS A GAP OF MORE THAN EVEN A FEW WEEKS, START ALL OVER AGAIN WITH LOW INTENSITY EXERCISE AS ABOVE.
8. Avoiding prolonged sitting in front of TV, computer or work desk or if possible, have frequent “standing” breaks.
9. Listening to your body : STOP exercising and go to your doctor or hospital if you have any of the following feelings at any time before, during or after exercise: tightness or heaviness in chest, unusual breathlessness, fainting or dizziness, nausea or vomiting sensation, pain the back, arm, jaw or throat or unusual gas or indigestion. It could be a warning sign of an impending heart attack.
10. Ensuring proper rest or sleep for 7 to 8 hours daily. If your sleep has been less the previous day or night, or if you have not rested well the previous day, skip the next exercise session or make it very light.
11. Finally one must remember, regular moderate exercise is no guarantee against heart disease if you also indulge in unhealthy eating habits or smoking or heavy alcohol consumption. So these have to go if you want be “heart-safe.”

In summary if you have been ‘screened’ properly (including a CACS, if deemed appropriate), if you make a gradual entry into an exercise program, building up your stamina and endurance slowly and safely, noting any unusual symptoms at any time, are leading a healthy lifestyle with diet, regular exercise and sufficient sleep,  using protective medications if advised and enough fluids, you are sure to minimize your chances of a heart attack and are on the  road to success without tears.