Heart Attack And Physical Activity

About heart attacks: what exactly is a heart attack?

Cardiovascular diseases (CVDs) are a group of heart and blood vessel disorders that are the leading causes of death globally. Covered by CVDs is myocardial infarction, also known as a heart attack. A heart attack occurs when blood flow in the artery decreases or stops in a part of the heart, causing damage to the heart muscle. The muscle nourished by the compromised artery begins to die if blood flow is not restored, reducing heart function, and possibly leading to cardiac arrest. More than four out of five CVD deaths are due to heart attacks and strokes, and one-third of these deaths occur prematurely in people under 70 years of age.1

Risk factors for heart attack include an unhealthy diet, physical inactivity, tobacco smoking, and harmful use of alcohol. All of these risk factors increase the risk of heart attack, stroke, heart failure, and other complications. Re-occurence of heart attack and other cardiovascular diseases are shown by individuals with raised blood pressure, glucose, and lipids, and also overweight and obese patients.2  

Symptoms of a heart attack

The most common symptom is chest pain, which can travel to the shoulder, arm, back, neck, or jaw. In addition, discomfort may occasionally cause heartburn in the centre of the chest. However, other uncommon symptoms could be present, such as shortness of breath, dizziness, nausea, chills and sweating, weak pulse, and cold and clammy skin.2,3 

Regular exercise can help decrease the risk of a heart attack

A sedentary lifestyle is a risk factor for heart attack, along with high blood pressure, abnormal blood lipid levels, smoking, and obesity. Many scientific studies have demonstrated that regular exercise has a favourable effect on many risk factors, promoting weight loss and blood pressure reduction, decreasing “bad” cholesterol (low-density lipoprotein or LDL) and total cholesterol level in the blood, whilst also raising the “good” cholesterol (high-density lipoprotein or HDL).

 In patients with diabetes, exercise improves the body’s ability to use insulin to control blood glucose levels. Thus, the effect of a continued, moderated exercise program, combined with other lifestyle modifications (such as proper nutrition, smoking cessation, and medication use) can be dramatic.4

Chest pains during exercise vs heart attack

During exercise or stress, the heart needs to supply a high demand for oxygen to the body, including its muscles. A mismatch between metabolic demand and oxygen supply can occur, resulting in inadequate coronary blood flow in the main heart muscle and myocardium. This interruption in blood flow leads to reversible myocardial ischemia or hypoxia (oxygen is not available at sufficient levels), causing chest pain or angina pectoris.

Although the mechanisms of angina are still unclear, myocardial ischaemia increases the regional pH, releasing factors that stimulate the nerve pathway, and transmitting the painful stimuli to the brain.5 

Angina is considered stable when associated symptoms of cardiovascular disease are precipitated by some activity (running, walking, etc.), with minimal or non-existent symptoms at rest. There is no increase in the frequency or severity of symptoms. Despite the term "stable", angina is a chronic medical condition associated with acute coronary events and increased mortality and should be managed. However, unstable angina is associated with other symptoms of cardiovascular disease, including worsening, becoming more frequent, or occurring at rest (or with minimal exertion). The most common cause is coronary artery narrowing due to a thrombus that develops in a disrupted atherosclerotic (fat) plaque, which may lead to heart attack, stroke, and death.5 

Be careful with strenuous exercise

What is strenuous exercise?

High-intensity or strenuous exercise refers to high metabolic energy demand during exercise. Exercise intensity can be expressed in absolute terms (e.g., oxygen uptake in litres per minute, power output in watts, heart rate in beats per minute, and speed of movement in metres per second or kilometres per hour).6

Strenuous exercise increases the immediate risk of a heart attack

Regular exercise is recommended to improve cardiovascular risk profiles. However, extremely intensive and competitive sports are dangerous. Recent studies have demonstrated that extreme volumes and/or intensities of long-term exercise training are associated with several possible cardiac maladaptations.7 

During strenuous exercise, especially in sedentary individuals, abrupt increases in blood pressure and ventricular contractility increase intravascular shear stress and may cause vulnerable atherosclerotic plaques to rupture, forming a nidus for thrombosis that can precipitate.8 Nevertheless, there is no clear threshold for the upper limit of exercise-induced health benefits.7 .

When to contact a doctor

Blocking blood flow in the heart may seriously damage the heart muscle. Eventually, the chest discomfort may only reduce to minor pain, similar to indigestion, rather than severe pain. Call a doctor immediately if you think you or someone else might be having a heart attack. Also, if you have stable angina which suddenly became unstable and severe, contact your doctor as soon as possible.9 

Conclusion

Heart attacks are one of the most common cardiovascular diseases, resulting from blocked or reduced blood flow to the heart muscle. Risk factors include a sedentary lifestyle, unhealthy diet, smoking, obesity, and abnormal blood lipid and glucose levels. 

The main symptom of a heart attack is chest pain (angina) that can also occur during exercise (stable angina), but differs from a heart attack due to its lesser severity and its association with physical activity. Unstable angina is unexpected and is associated with other symptoms of cardiovascular disease, becoming more frequent or occurring at rest. Unstable angina may worsen over time and lead to a heart attack. 

However, it is possible to prevent a heart attack (or having another heart attack); quitting smoking, losing weight if you are overweight or obese, eating healthy, and moderating alcohol consumption are good ways to take care of your heart. Although strenuous exercise was shown to be dangerous and increase the immediate risk of heart attack, especially for sedentary individuals, regular moderate-intensity exercises are almost always beneficial in reducing all risk factors. 

References

  1. Cardiovascular diseases [Internet]. [cited 2022 Sep 21]. Available from: https://www.who.int/health-topics/cardiovascular-diseases#tab=tab_1
  2. Cardiovascular diseases [Internet]. [cited 2022 Sep 21]. Available from: https://www.who.int/health-topics/cardiovascular-diseases#tab=tab_1
  3. Quah JLJ, Yap S, Cheah SO, Ng YY, Goh ES, Doctor N, et al. Knowledge of signs and symptoms of heart attack and stroke among Singapore residents. Biomed Res Int. 2014 Apr 10;2014:572425.
  4. Myers J. Cardiology patient pages. Exercise and cardiovascular health. Circulation. 2003 Jan 7;107(1):e2–5.
  5. Anderson L, Dewhirst AM, He J, Gandhi M, Taylor RS, Long L. Exercise-based cardiac rehabilitation for patients with stable angina. Cochrane Libr [Internet]. 2017 Sep 25; Available from: https://doi.wiley.com/10.1002/14651858.CD012786
  6. MacIntosh BR, Murias JM, Keir DA, Weir JM. What Is Moderate to Vigorous Exercise Intensity? Front Physiol. 2021 Sep 22;12:682233.
  7. Eijsvogels TMH, Thompson PD, Franklin BA. The “Extreme Exercise Hypothesis”: Recent Findings and Cardiovascular Health Implications. Curr Treat Options Cardiovasc Med. 2018 Aug 28;20(10):84.
  8. Schwartz BG, Mayeda GS, Burstein S, Economides C, Kloner RA. When and why do heart attacks occur? Cardiovascular triggers and their potential role. Hosp Pract . 2010;38(3):144–52.
  9. Heart attack [Internet]. nhs.uk. [cited 2022 Sep 22]. Available from: https://www.nhs.uk/conditions/heart-attack/

Dayene Caldeira

Masters and PhD candidate in Biological Sciences (Physiology), Federal University of Rio de Janeiro, BR

Visiting Researcher at Queen's University Belfast, UK.
Dayene is a scientific expert experienced in Clinical Data Management and Medical Communication. She has 6 years of experience in Publications, Grant submissions and Regulatory documents in the Medical Writing field. Currently, working with medical education and patient engagement, creating materials about different diseases and therapeutic areas.

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