Heart disease (or cardiovascular disease) is the number one cause of death in developed countries. It includes a number of problems that can develop with the heart and the circulatory system. Heart disease is generally caused by a combination of genetic dispositions in combination with unhealthy lifestyle factors especially food choices. Unlike many other diseases, the risk of heart disease can be dramatically reduced by people making healthier choices in terms of nutrition, exercise, weight control, and stress management.

The primary process underlying most forms of heart disease is atherosclerosis. Atherosclerosis is a condition in which the arteries’ inner walls thicken and harden due to deposits of substances called plaques. This is a primary feature of coronary artery disease and can lead to heart attacks, strokes, claudication of the limbs, impotence in men, and other negative effects.

If plaque builds up in the coronary arteries, the blood vessels that feed the heart, the muscle of the heart can be gradually weakened and damaged. When this happens, the heart may start to beat irregularly, and become unable to properly pump blood to the rest of the body’s organs. In some cases, a plaque can break open, spilling material that lodges deeper in the artery, triggering blood clotting that can block the artery entirely. If this happens to an artery feeding the heart, the tissue beyond the blockage will be suddenly starved of oxygen and begin to die. This is known as a myocardial infarction, or heart attack. This can be fatal, but even if a person survives, the heart tissue killed in a myocardial infarction does not grow back, leaving the heart permanently injured and more vulnerable to another heart attack in the future. Recently developed experimental therapies using stem cells injected directly into the heart have shown an ability to reverse this damage.

Another risk is blockage of blood vessels supplying oxygen to the brain. When this happens, brain cells quickly start dying. This is the most common form of stroke.

The main form of atherosclerosis involves the buildup of a soft type of plaque known as vulnerable plaque. This may be triggered by excessive levels of low-density lipoprotein cholesterol (LDL-C, or “bad” cholesterol) in the blood. As LDL accumulates, it oxidizes and attracts white blood cells. White blood cells that have consumed fatty LDL until “stuffed” are known as “foam cells.” The presence of foam cells can trigger the immune system to begin a cycle of inflammation that causes more vulnerable plaque to accumulate. The immune system will create a fibrous “cap” over the vulnerable plaque to wall it off from the bloodstream and contain the problem. The cap is primarily made of collagen and calcium. This capped plaque is called an atheroma.

Yet formation of a fibrous cap over a plaque does not end the danger. As the plaque grows on the artery’s inner wall, it makes it harder for blood to flow through. Over time, the arteries stretch and expand to accommodate this blood flow, and in the process harden. This makes them less flexible to expand and contract with each heartbeat. If someone has high blood pressure, such as when doing strenuous work, the extra tension can cause a fibrous cap to rupture. The contents of the plaque then travel through the artery and cause a blockage, or spur formation of a blood clot, called a thrombus, that comes loose and causes a blockage itself. Depending on where the blockage occurs and how severe it is, this can result in fatal heart attacks and strokes.

See these links for more on atherosclerosis:

• Basic overview of heart disease from the Mayo Clinic.¹
• Quick two-minute visual intro to atherosclerosis.²
• More in-depth explainer video about atherosclerosis and related conditions,³ including key terms and complications caused in other parts of the body.
• Detailed animated view of how atherosclerosis works.⁴

High blood pressure (or hypertension) is another common condition. This can be aggravated by smoking cigarettes and excess weight. Hypertension can cause or worsen a related problem, arrhythmia. This is where the heart beats abnormally, which can cause clots to form and trigger a heart attack or stroke. Congestive heart failure is where the heart becomes too stiff or too weak to pump as much blood as the body needs. This can be worsened by high-stress lifestyles, or by being overweight or obese. For more on the causes of heart disease, see these informative videos:

• Caldwell Esselstyn⁵ on the idea that heart disease is a food-borne illness, explaining the role diet plays in cardiovascular health.
• Short CNN clip⁶on the links between stress and heart disease. Includes practical tips for reducing stress.
• Rhonda Patrick⁷ speaking on the Joe Rogan show about the causes of heart disease, described in clear and understandable language.

All these conditions can be improved or eliminated by maintaining an active lifestyle. People who exercise regularly have lower blood pressure and are less likely to develop atherosclerosis; the heart muscle stays healthy, and it is easier to stay the right weight for a person’s body type. When exercise is combined with a healthy diet, no smoking, and no more than moderate alcohol consumption, a person’s risk of cardiovascular disease is likely to be greatly reduced.

If you take a leadership role in encouraging people to follow healthier lifestyles, you can have a great impact in lowering the likelihood of heart disease. As a young person, three ways to do this are bringing groups together (for example, starting a club), creating tools (programming an app), and motivating action (telling stories that inspire people to change their habits). Here are some ideas for how you might do this to influence dietary factors:

• Start a club. Becoming a champion for healthy eating habits in your community is a perfect place to begin. Start a healthy eating club⁸ at your school. Together, you can watch videos about the science of food and wellness, ask for more nutritious options in the cafeteria, or learn to cook heart-healthy snacks on your own.
• Build an app. If you know computer programming, you could design an app that helps people establish good eating habits. Think of how you could make it easier for people to find healthy foods at reasonable prices, set good diet goals, and hold each other accountable for eating things that will keep your hearts healthy. If you haven’t learned to code yet, check out the entry for “How You Can Be a Danielle and Learn to Program Computers from a Young Age.”
• Tell a story. If your talents lie in the arts, you could create series of videos or a documentary to show people in a creative way why it’s important to have a good diet. Or you could work with other students, sharing your experiences with them and mentoring them on healthy food. If your parents and family members don’t have health-promoting habits, encourage them to make a commitment to wiser eating, such as explained by Dr. Maya Adam⁹ in this video.

The same principles apply to exercise, and getting people to spend more time outdoors and moving their bodies:

• Start a club. Becoming more active is easier when you’re doing it with friends. Action for Healthy Kids¹⁰ is an alliance of organizations that encourage young people to stay active and fit. They provide resources that can guide you on starting a fitness club at your school.
• Build an app. There’s lots of room to be creative in designing fitness apps, and many different kinds of exercise. Think of how you could make physical activity more enjoyable, and how you can help people set goals and feel gratified when they accomplish them. One of the best motivators to exercise is when it doesn’t feel like a chore. For example, in 2016 the augmented reality game Pokémon Go got hundreds of millions of people to go out walking and jogging—not just to meet fitness goals, but for the fun of finding and catching digital monsters in public places. Take a look at ARCore¹¹ by Google, which recently released a new set of tools to help people develop augmented reality apps of their own.
• Tell a story. The American Heart Association¹² has lots of resources to help you inspire people in your community about healthy living—from diet and exercise to ways to quit smoking and reduce stress. This includes the stories of real people who have transformed their lives for the better. The Healthy for Good movement¹³ helps people get motivated to make healthy choices and keep making them.

In addition to healthy lifestyle campaigns, there is also cutting-edge medical research being conducted to better understand how heart disease works and how to cure it. The best of this research is highly innovative, and gets ideas from unexpected fields. Here are just a few examples:

• This TED Talk by biomedical scientist Nina Tandon¹⁴ on how tissue engineering can help people get the right treatments for their own organs, such as the heart.
• A fascinating story by engineer Tal Golesworthy¹⁵ on how he repaired his own heart, using creative thinking from outside medicine.
• Consider supporting the British Heart Foundation,¹⁶ which funds key research into the molecular-level factors driving heart disease, which may ultimately make cures possible.
• Another organization worth your support is the Children’s Heart Foundation,¹⁷ which drives research on congenital heart problems that affect children.

If you want to obtain a deeper understanding of heart disease, or pursue a career researching ways to cure it, you should take the most challenging biology, chemistry, and math courses you can. If you’re ready, you can also start college-level study with online courses related to heart disease and heart health, such as these introductory options:

• Easing the Burden of Obesity, Diabetes, and Cardiovascular Disease,¹⁸ a 5-week course by the University of Sydney. It is a college-level course, but does not require any prior background in medical science.
• Science of Exercise,¹⁹ a 4-week course from the University of Colorado Boulder, covers how exercise works in the body, and the benefits that result. It is aimed at beginners.
• Understanding Obesity,²⁰ from the University of Edinburgh, is a 4-week course on the effects of obesity on health, including heart disease, and how obesity can be prevented. No prior experience necessary.
• Introduction to Food and Health,²¹ from Stanford University, is a 5-week course for beginners on how better diet can improve health and reduce problems like cardiovascular disease. Includes a focus on the relationship between lifestyle and diet, and covers practical ways to form and maintain healthier habits.

If you’re motivated, you can start working on curing heart disease right now, even at a young age. Here are a few suggestions on how (which also apply to cancer research, as explained in the entry for “How You Can Be a Danielle and Help Cure Cancer”):

• Read academic journals about medicine, and look for a novel way to connect the problems you read about to ideas from other subjects, like chemistry, biology, or engineering.
• Build your skills at doing lab experiments. MIT OpenCourseWare offers helpful online courses on experimental biology²² and laboratory chemistry.²³
• Look for professors or labs in your area who can mentor you. Ask them questions based on your reading, and suggest ideas for experiments they could help you do.
• Think about whether you have skills not usually applied to treating heart disease, which might be an opportunity for innovation. For example, if you’ve learned computer programming in areas like artificial intelligence and machine learning, consider how those techniques might make it easier to detect or treat cardiovascular problems.

For more information, please see the following entries in the companion book A Chronicle of Ideas: A Guide for Superheroines (and Superheroes): Arterial Calcification, Fetal Bone, Fetal Organ, Atherosclerosis.