Recent research shows that three years of taking aspirin daily is associated with a small reduction in heart attacks only in people who have had previous heart attacks, but not in those who had not had a previous heart attack (Clin Cardiol, May 2017). Previous studies have shown similar results (Am J Med, Feb 2015;128(2):137-43).
People aged 50 to 70 are more likely to benefit from taking aspirin than those in other age groups. However, daily aspirin increases risk for bleeding in your gut that can cause stomach ulcers or into your brain that can kill you. The American Heart Association (AHA) recommends that you take daily aspirin only if your chance of developing a heart attack in the next 10 years is greater than five percent (Ann Intern Med, June 21, 2016;164(12):826-35). They do not recommend that most people over 70 take aspirin regularly because of their increased risk for bleeding.
You are considered to be at high risk for a heart attack if you have had:
- a previous heart attack or stroke
- a stent placed in the arteries leading to your heart. Almost all patients with stents are prescribed some type of anti-clotting medication.
- previous heart bypass surgery
- angina (chest pain due to coronary artery disease)
- diabetes with at least one other heart disease risk factor such as smoking or high blood pressure
- perhaps very high cholesterol, triglycerides or blood pressure
Risks of Taking Aspirin
Even very low–dose aspirin (one baby aspirin a day or every other day) increases risk for gastrointestinal bleeding by 58 percent and hemorrhagic stroke by 27 percent, and these risks increase with increasing age (Ann Intern Med, June 21, 2016;164(12):826-35). I recommend that you should not start aspirin therapy without first consulting your doctor. You are at increased risk for being harmed by taking aspirin if you:
- have an aspirin allergy or intolerance
- are at increased risk for bleeding for any reason
- are at risk for falls or are often in situations where you may bang your head or be pushed or shoved
- drink alcohol regularly. The combination of alcohol and aspirin puts you at higher risk for intestinal and stomach bleeding.
How Aspirin May Help to Prevent Heart Attacks
Heart attacks and most strokes are not caused by narrowed arteries. They are caused by a sudden complete blockage of blood flow to the heart or brain. First, a plaque breaks off from the inner lining of an artery leading to your heart or brain. Then that spot bleeds and a clot forms. Then the clot extends to block completely all blood flow to the heart or brain. The heart muscle then suffers from lack of oxygen and dies.
Aspirin can help to prevent blood clots from forming and therefore help to prevent heart attacks and strokes. When a person is at very high risk for forming clots, doctors often prescribe other drugs with aspirin, such as clopidogrel, prasugrel or ticagrelor.
One daily baby aspirin (81 mg) has been shown to help prevent clotting. An adult aspirin equals four baby aspirins, or 325 mg. Many people believe that taking buffered or enteric-coated aspirin will protect them from stomach bleeding, but these products do nothing to reduce risk of bleeding into the brain and they still can cause gastrointestinal bleeding. If you and your doctor decide that you should be taking aspirin, he or she will recommend your specific dose.
Caution on Stopping Daily Aspirin
If you have been taking a daily aspirin, never stop taking it suddenly. You can suffer a rebound increased risk for clotting from stopping aspirin suddenly, which puts you at increased risk for a heart attack. If you are going to stop taking aspirin after taking it for a while, your doctor will tell you how to gradually taper off your dose. If you are planning to have any surgical ordental procedures, your doctor or dentist is likely to tell you not to take aspirin for a week before the procedure; check with your doctor for instructions on tapering.
Should You Take an Aspirin If You Think You are Having a Heart Attack?
Taking an aspirin should never take the place of getting emergency help as fast as possible. If you develop chest pain that makes you think that you are suffering a heart attack, call 911. You only have approximately an hour and a half for doctors to open a blocked artery leading to the heart. After that, the oxygen-starved part of the heart muscle dies, and you can develop an irregular heartbeat that can kill you.
Often, emergency personnel will give aspirin while they are rushing you to a hospital or after you enter an emergency room with a suspected heart attack. There is data to show that taking an aspirin at the start of a heart attack can decrease clotting, and that chewing an adult aspirin gives you a more immediate inhibition of clotting than swallowing the pill whole. Chewing an adult aspirin tablet for 30 seconds before swallowing it on an empty stomach caused a 50 percent reduction in platelet activity in five minutes, compared to 12 minutes when the aspirin was swallowed whole (The American J of Cardiology, August 15, 1999;84(4):404–409).
Never take aspirin if you think you may be having a stroke. Many strokes are caused by bleeding, and aspirin increases bleeding. Again, dial 911 immediately.
Lifestyle Factors that Affect Risk for Clots
Risk for forming clots increases with age. What you eat and what you do influences your susceptibility to forming clots. You increase risk for clotting by:
- being overweight
- being immobile, such as on a long trip in a car or plane
- taking oral contraceptives
- having a family history of blood clots
- having chronic inflammatory diseases
- having diabetes that is not tightly controlled
You can help to decrease risk for clotting by:
- losing excess weight
- avoiding smoking and smokers
- lowering high cholesterol
- lowering high blood pressure
Follow your doctor’s recommendations, but whether you take aspirin, statins or any other drugs, make the lifestyle changes that are known to prevent heart attacks at any age.
Gabe Mirkin, M.D., is a sports medicine doctor and fitness guru. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin has run more than 40 marathons and is now a serious tandem bike rider with his wife, Diana. His website is http://drmirkin.com/. Click to read Gabe’s full bio.