What time of the day is best to take a baby aspirin for heart health purposes?

Glad you asked! Aspirin irreversibly binds platelets for the life of the platelet (which is 10 days). Every day, our bodies make new platelets replacing the 10% that is lost. When you take one single aspirin, you have an antiplatelet ("blood thinning") effect that lasts at least 5 days (50% of your circulating platelets). Bottom line: it doesn't matter what time you take the aspirin. The effect lasts a long time.

Related Questions

I already take a baby aspirin for heart health. Can I take a higher dose for hip pain after a fall?

Yes and no. Aspirin interferes with blood clotting mechanisms. Therefore immediately after a fall if there is any suspicion of active bleeding it should not be used along with other agents, such as ibuprofen. After a fall with resulting in hip pain I would be concerned with impending hip fracture versus muscular trauma which requires a thorough examination. If there is no danger adult dosage may be used.

What is the best time of the day to take a baby aspirin for heart therapy purposes?

Night. Studies show heart attack occur early in the morning when blood flow slows down - Aspirin also helps with night muscle aches so helps both ways.
With food. Several guidelines recommend early use of single doses of Aspirin in various ranges as prophylaxis against cardiovascular events. The dose of Aspirin varies not only with the indication but also between different guidelines. There is no particular time frame identified, but in general an Aspirin tablet should be taken with a small meal.
Any time. Aspirin's antiplatelet effect lasts for approximately 8 days; therefore, it does not matter what time of day one takes a daily dose.

According to current thinking, is one 81 mg. Aspirin advised over two 81 mg. Aspirins to maintain heart health in the "average" healthy person?

One is ok. Risk vs benefits vary for each person. Consult your physician. But, the actual data to prevent heart attack and stroke point toward the use of low dose Aspirin and 81 is enough. Aspirin, as an anti inflammatory agent, seem to have other benefits. A study show that low dose may reduced chances of dying from cancer 20%. American cancer society is not recommending asa as prevention measure, still.

Is ibuprofen safe, short-term, (one to two days), for toothache relief even though I am taking a daily 325 mg aspirin for preventive heart health?

Pharmacy. Combination of Aspirin and Ibuprofen can be problematic. And unless your doctor told you to take an adult Aspirin I would recommend a baby Aspirin 81 mg. Less chance of GI problems but still heart healthy but check with your doctor.
See dentist. You increase your risk of GI problems if you take both Aspirin and ibuprophen together. Get your tooth treated asap. Talk to your dentist and md regarding the best and safest pain medication for your toothache.
Take Tylenol (acetaminophen). Since you are already taking a non-steroidal anti- inflammatory agent (aspirin) a good short term option is tylenol (acetaminophen). This should prevent both the potential stomach upset and the potential for increased bleeding from taking both Aspirin and Ibuprofen together.
Aspirin or tylenol (acetaminophen) Analgesic dose of aspirin, taking Motrin atleast 1 hour after taking Aspirin to minimize interference with antiplatelet effect of Aspirin and tylenol (acetaminophen) are possible options.