A normal head of hair contains about 120,000–150,000 strands of hair. Usually, at any one time, about 90% of those hairs are in a growing phase, growing by about 1/2 inch each month. This phase lasts for two to three years. At that point, a hair will go into a resting stage. This “rest” lasts for 3 to 4 months before the hair falls out and is replaced by a new one.
“Typically, people shed about 100 hairs a day,” says Carolyn Jacob, MD, founder and medical director of Chicago Cosmetic Surgery and Dermatology. “Most people don’t even notice.”
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 tells WebMD, can be caused by the substantial physiological stresses on your body.
But, according to Amy McMichael, MD, professor of dermatology at Wake Forest Baptist Health in Winston-Salem, N.C, 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 only 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.
Stress and Hair: What Causes Hair Loss?
A variety of stressors may cause your body to undergo hair loss. It happens, McMichael says, when there’s some type of physiological change in your system. “For instance,” she says, “you go on or off an oral contraceptive. Or you lose more than 15 pounds of weight. Things like this change the physiological balance in your system.”
Other stressors, according to McMichael, could include:
Being on a strict low-calorie diet
After childbirth when estrogen levels fall
Having a high fever
Having major surgery
Mirmirani says that hair shedding can also result from certain medications such as some type of blood pressure medications, thyroid disease, and nutritional deficiencies such as vitamin D or excess vitamin A.
Pinpointing the actual cause of the shedding isn’t always easy. That’s because, Mirmirani says, there’s a three- to six-month lag time between the stressful event and the hair loss. In order to determine the cause, you need to look back at what was happening three, six, or even nine months before the hair loss began.
Stress and Hair: The Physiological & Emotional Connection
“If you’re going through a very severe divorce,” McMichael says, “you might not be eating properly; you might lose weight or not sleep well. You may go off and then back on your oral contraceptives.” All of these things cause physiological stress and an imbalance in your system. “The point is,” she says, “there are a lot of other things that are physiological going on. You’re not losing your hair because you hate your ex-husband.”
McMichael says that women have a number of things that happen on a regular basis that they may not recognize as stressors. “You start out your life and you’re fine,” she says. “You’re 20 years old and get married. You get on some oral contraceptives. Well, that causes shedding.”
When a woman decides to have a baby, if she is taking them, she will stop taking oral contraceptives. “Maybe you have a little bit of shedding related to that. And then you get pregnant.” Pregnancy causes the body to keep the hair that normally would fall out as part of the regular hair cycle, so a woman may notice her hair may feel extra thick and fuller during that time. After giving birth, all the hair that would have fallen out is shed three to six months later.
“Also, after birth,” McMichael says, “you realize you’ve gained 30 pounds and go on a diet to lose it. That causes shedding. But somewhere in all this, someone in the family dies and, because you’ve heard that stress causes hair loss, you say, ‘Oh my God, I’m losing my hair because someone died.’ But that’s not it. You’re losing hair because you lost 30 pounds.”
“It’s not a foregone conclusion,” McMichael says. “Not everyone gets these episodes of hair loss. Some women go on and off of contraceptives and never have shedding. Some have seven children and have no hair loss related to it.” McMichael does point out that once you have shed hair in response to a physiological stress, you are likely to do it again.
McMichael says that because people have repeated the myth of a direct connection between emotional stress and hair loss for so many years, many people now believe it. Jacob tells WebMD. “There’s no way to predict who’s going to lose hair and who’s not. If you’re a shedder, you’ll shed.” She also says there’s no scientific evidence that points to specific emotional stresses that might trigger the physical stress that can lead to hair loss.
Ladies, has stress ever affected your hair?