In one sentence, describe what the following article is about:

The risk of having a first-time blood clot (VTE) is 100 in 100,000. However, that risk goes up exponentially as we age: by age 80, the rate of VTE is 500 in 100,000. As you get older, it’s important to monitor your overall health with regular medical checkups. Recent surgery or a broken bone in your hips or legs increases your risk of blood clots. Those who lead a sedentary or inactive lifestyle are at higher risk of pulmonary embolism, or a blood clot in the lungs. People who sit more than six hours a day in their leisure time are twice as likely to have pulmonary embolism of those sit for less than two hours. Prolonged periods of lying, sitting, or standing in one place can cause blood stasis, leading to clots. This is one reason why VTE is so common in hospitalized patients, especially after surgery, and people traveling long distances. People who fall in to the obese category have a much higher risk of VTE than those in a healthy weight range. The correlation is not completely understood, but experts believe at least part of it is due to the estrogen produced by fat cells. Estrogen is an independent risk factor for blood clots. Fat cells also produce proteins called “cytokines,” which may play a role in formation of  VTE. Though not always the case, the obese may also lead more sedentary lives than those who fall into healthier weight ranges.  To calculate your BMI, use an online BMI calculator, like the one on the Mayo Clinic website. You will need to input your age, height, weight, and sex for your results. An obese person will have a BMI of 30 or more. The overweight range is from 25-29.9, and normal from 18.5 to 24.9. Anything below 18.5 is considered underweight. Hormonal shifts, especially those involving estrogen, can put people at risk of VTE. This is often seen in postmenopausal women who take estrogen supplements as part of hormone replacement therapy. Women who take hormonal contraception to prevent pregnancy and those who are pregnant are also at risk. Before beginning any hormone therapy, discuss the risks and your options with your doctor. Coagulation is just another word for clotting, which is a normal process for your blood. Without it, you would bleed to death if you cut yourself! While coagulation is normal, hypercoagulation is when the blood clots too much, even when it's still in the body. Hypercoagulation can be caused by long periods of sitting or lying down, cancer, dehydration, smoking, and hormone therapies. You are at risk of hypercoagulation if:  You have a family history of abnormal blood clots. You personally had a blood clot at young age. You had blood clots during pregnancy. You've suffered from multiple unexplained miscarriages. Some genetic disorders, such as Factor 5 Leiden Disorder or Lupus Anticoagulant, can also cause this condition. Atrial fibrillation (irregular heartbeat) and the build up of cholesterol plaques in your arteries can all lead to blood clots.  If you have atrial fibrillation, your blood isn't flowing properly, and may pool and begin to clot.  People with atrial fibrillation may notice an irregular pulse but no other symptoms; it is usually discovered during routine check-ups. It can be treated with blood thinners or other medications, lifestyle changes, and in some cases a pacemaker or surgery.  Waxy cholesterol plaques can build up in your arteries (sometimes as part of atherosclerosis) and, if the plaques break, they can begin the clotting process. Most heart attacks and strokes occur when plaque in your heart or brain bursts.

Summary:
Raise your awareness with age. Consider your activity level. Calculate your body mass index (BMI). Pay attention to your hormone levels. Be aware of a hypercoagulation. Learn about other health conditions that increase the risk of blood clots.