High blood pressure – Defined at 140/90 mmHg, but… anything above 120/80mm Hg is above normal. Blood vessels may thicken and weaken in response to high blood pressure. Over time, that affects normal blood flow to the brain, reduces attention span, learning, memory and the ability to make decisions. High blood pressure may be the number one cause of vessel damage in the brain.

Note: One in three adults has high blood pressure. One in three adults isn’t aware they do. Of those being treated for high blood pressure, two-thirds do not have it under control. Regular blood pressure checks are a critical tool for maximizing brain health.

It increases the risk for heart disease, stroke, high blood pressure, diabetes and more—conditions known to harm brain cells. Fat cells may also release hormones that cause inflammation.

Studies have shown a 2- to 3-fold increase in the risk for dementia and Alzheimer's disease in people whose diets contain large amounts of saturated and trans fats. Diets that raise blood cholesterol may also increase the build-up of a type of plaque in the brain (called beta-amyloid) that's associated with Alzheimer's.

Diabetes is a significant risk factor for dementia. One study found it nearly doubled the risk. Like high blood pressure, many people are unaware that they have the beginnings of diabetes (a fasting blood sugar of 100-125). Diabetes can damage arteries which in turn may lessen blood flow to the brain and damage brain cells. People with type 2 diabetes may also have high levels of insulin circulating in their blood. High levels of insulin might affect the body's ability to break down beta amyloid (the protein that forms the plaque associated with Alzheimer's).

A high blood cholesterol level is an indication of plaque build-up inside your arteries. A recent study of people with total cholesterol levels between 249 and 500mg/dL found they were one and one-half times more likely to develop Alzheimer’s than people with cholesterol levels below 198. Having a cholesterol level between 221 and 248 increased risk as well.

Scientists believe smoking damages brain tissue. It affects nerve cells and alters the chemical make-up of the brain. Quitting smoking can restore the chemical balance.

Whether you're a little tyke or a grandparent, sleep is needed to enhance the connections between brain cells. Studies suggest that connections between nerve cells in the brain depend on getting an adequate amount of "deep sleep." Growing and keeping those connections allows your brain to thrive. Too little sleep means less than optimal connections.

An inactive lifestyle increases the risk of many diseases that have an impact on the brain including, heart disease, obesity, diabetes and hypertension (high blood pressure). Inactivity results in less than the best blood flow to the brain.

Inflammation is your body's response to injury and its attempt to try and heal itself. A measured amount of inflammation is good for healing, but when the body believes it’s in a constant state of repair, it becomes unhealthy and harmful. The buildup of plaque inside arteries triggers inflammation, so too does stress, smoking, environmental pollutants and a diet high in fat. Inflammation damages healthy cells.

Whether caused by an accident or impact from a sports-related event or injury, brains cells are damaged.

Our bodies respond to stress with a cascade of chemical changes that increase the blood’s capacity to clot. Stress also increases blood pressure. It constricts some blood vessels and releases fats into the bloodstream. All in all, it seems to have a lasting harmful impact on brain cells.