Chronic (prolonged) elevation of blood pressure can causer hypertrophy and hyperplasia. This can lead to an increased resistance in catecholamines (adrenalin) causes the heart to pump harder and faster. This can cause an increased resistance as blood vessels also constrict. This gives the heart muscle a lot of resistance to pump against. Because the body needs oxygen and nutrients, the cells adapt by growing more cells and bigger cells to work better.

An imbalance in hormones can lead to hyperplasia and/or hypertrophy. For example, a thyroid can produce too much or not enough thyroid hormone. This can lead to a goiter. A goiter is used to describe an abnormal thyroid growth caused by hyperplasia of thyroid cells.

Good nutrition is essential to cell survival. If cells do not have enough nutrients, they must adapt or eventually die. Cells may increase in cell SIZE or NUMBER to survive. An example of this is iron deficiency anemia. The body creates more red blood cells to counteract the lack of oxygen available to the body.

Cells NEED more oxygen. If cells do not have enough oxygen, they will adapt by making MORE or LARGER cells. These new cells need oxygen as well, which could lead to even more hypertrophy or hyperplasia. An athlete uses high levels of oxygen to compete. If they train hard for long periods, the cells of the heart adapt by becoming LARGER. This leads to a condition called “Athlete’s Heart” or Athletic Heart Syndrome, which is a normal Hypertrophy.