Sometimes, a significant stress of some sort may spark a change in your body's routine physiological functions, Jacobs says, and cause a disproportionate number of hairs to go into the resting phase at the same time. Then three to four months later, sometimes longer, all those resting hairs are shed. The effect can be alarming.
The types of events that disrupt the normal hair cycle, Jacob says, can be caused by the substantial physiological stresses on your body.
But, according to McMichael, physiological stress is not the same as emotional stress. Hair loss can be one way the body responds to significant physiological stress that may be brought on by diet, medical, or lifestyle changes.
"Only those things that cause physiological stress can cause a hair loss event," McMichael says. The good news is that the hair loss from these kinds of events is usually temporary, as long as the stress event is temporary. Once the stressor is addressed or goes away on its own, hair grows back and the normal hair cycle resumes.