What occurs to bone density when there is significant stress on the bone?

When significant stress is applied to bone, such as through weight-bearing activities or resistance training, bone density typically increases. This phenomenon is known as Wolff's Law, which states that bone adapts to the loads under which it is placed. The mechanical stress stimulates bone-forming cells called osteoblasts to increase new bone formation, thereby enhancing bone density.

In contrast, if bones experience little to no stress, such as in cases of prolonged immobility or bed rest, they can lose density. Therefore, maintaining an active lifestyle with appropriate weight-bearing exercises is crucial for bone health. Other options, including fluctuations in bone density or it remaining unaffected, do not accurately represent the physiological response to stress on bones.