The heart is the most vital organ in the body, responsible for pumping blood that carries oxygen and nutrients to all tissues. Its health is essential for overall well-being, and most cardiovascular diseases—conditions that affect the heart and blood vessels—can be prevented by improving diet, sleep, physical activity, and stress management. In France, 15 million people are being treated for cardiovascular risk, with heart attacks and strokes being the leading causes of death among women. Awareness of these risks is the first step toward better prevention. The heart functions as a pump that connects to the blood circulation system, sending blood into the arteries to distribute oxygen and nutrients throughout the body. At rest, the average heart rate ranges from 50 to 80 beats per minute. For the system to function properly, all parts of the heart—such as the muscle, valves, arteries, and veins—must be in good condition. Poor lifestyle choices, like a poor diet, lack of physical activity, smoking, and chronic stress, are linked to most cardiovascular diseases. Physical activity is essential for heart health, as it increases the heart rate to supply muscles with more oxygen and glucose. During physical effort, working muscles release substances like cytokines, which help relax the arteries and promote the growth of small blood vessels. This reduces inflammation, strengthens the immune system, and triggers the release of endorphins, which help reduce stress. Regular exercise makes the heart muscle more efficient, requiring less effort for the same physical activity and speeding up recovery. The heart is in constant communication with the brain. Stress can activate the sympathetic nervous system, causing the heart to beat faster. Chronic stress can lead to inflammation and activate blood clotting mechanisms, which can be dangerous for arteries. Physical activity and stress management techniques are essential for countering these effects. Women are relatively protected from cardiovascular diseases by hormones such as estrogen and progesterone but are more vulnerable during certain life stages: young women using estrogen-progestogen oral contraceptives, during pregnancy, and during menopause. Hormone replacement therapy for menopause can increase cardiovascular risk. A diet rich in fruits, vegetables, whole grains, and fatty fish, with limited animal fats and salt, is recommended for cardiovascular health. The Mediterranean diet is particularly protective, as it provides the intestinal microbiota with elements needed to synthesize serotonin, a naturally anti-stress neurotransmitter. Limiting salt intake to 4 to 6 grams per day and reducing sugar consumption are also advised to protect the heart. Regular physical activity, including at least 30 minutes of cardiorespiratory activity five days a week and one to two weekly sessions of strength training, is recommended. Monitoring heart rate can be useful for heart patients, but for those in good health, monitoring breathing is sufficient. Physical activity can be safely resumed after a heart attack, reducing mortality by 30%. Stress management is crucial for cardiovascular health, as it can raise blood pressure and cholesterol levels, encourage smoking, and promote unhealthy eating. Techniques such as physical activity, spending time in nature, breathing exercises, meditation, and cognitive-behavioral therapy (CBT) can help manage stress. Different stress profiles require tailored approaches, such as CBT for the depressed or EMDR for those with post-traumatic stress. Risk factors to monitor include high cholesterol, high blood sugar, and high blood pressure. Regular blood tests and lifestyle changes such as a Mediterranean diet, physical activity, and stress management are recommended. Symptoms such as palpitations, shortness of breath, syncope, and heart murmurs should not be ignored and may require medical attention. Cardiologists recommend books such as Three billion beats. The secrets of our heart by Dr. Emmanuelle Berthelot and The heart of happiness. I decided to be happy to avoid a heart attack! by Dr. Jean-Pierre Houppe for further reading.