I confess, as a hair restoration surgeon and physician, that I’m a “Game of Thrones” junkie. I love the fictional world of Westeros, and especially the character of Daenerys of the House Targaryen (played by Emilia Clarke) and her fire-breathing dragons. I have watched every single episode since the first season. Like most GoT fans, I anxiously await the fate of the characters and who will next sit on the Iron Throne to rule Westeros.

An enduring saying used in the fictional world of GoT is “winter is coming.” It’s the motto of one of the main families (the House of Stark) competing for power in Westeros. The term has been a metaphor and meme for the last six seasons and suggests an unpleasant future as fans realize the undead White Walkers of the underworld maneuver to control the fictional world of Westeros. To some, though, the phrase expresses the instinctive need to prepare for the challenges winter brings to our daily lives. GoT author George R.R. Martin used the phrase to convey the emotional imagery of stealthy or dark periods in our lives. “Winter” requires us to always be ready for an unknown or fearsome future.

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As the series moves into its 7th season, we, as human beings living in the 21st century, face something similar. Winter has passed and we’re now in spring, but summer is coming. Many don’t realize that seasonal changes impact us physically, sometimes adversely impacting our health and well-being. For example, we can experience seasonal depression and mood changes (like seasonal affective disorder), seasonal allergies or seasonal dermatitis.

The change in seasons can impact our daily lives, including hair quality, growth and cycle. It’s common to shed up to 100 hair follicles per day. In some patients, certain seasons were anecdotally associated with more hair loss than others. While we all experience some amount of daily hair shedding, you might start noticing that you’re shedding more than usual during the summer months.

Summertime hair loss is real, and research suggests that women experience elevated rates of hair shedding due to hair follicles entering a resting phase, known as telogen effluvium, or TE. When hair is subjected to more extreme weather, perhaps as much as 70 percent of hair follicles can prematurely enter this resting phase, leading to more hair shedding than usual. This may explain why many women experience greater hair loss in July and August when the temperature really heats up outside.

To understand hair loss, it’s important to know the cycle of the hair follicle. Hair follicles are not always in the active growth stage. A hair follicle cycles through a growth (anagen) phase that can last two to seven years, then the hair follicle transitions to a regressing (catagen) phase lasting a couple of weeks. Afterward, the hair follicle enters the final phase (telogen) for up to two to four months. The hair follicle is then shed when the hair follicle root reenters a new growth cycle. At any time on a healthy human scalp, about 80 to 90 percent of the hair follicles are growing hair. That leaves up to 10 to 20 percent of scalp hair follicles in a resting state.

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Telogen effluvium is the second most common form of hair loss. Generally speaking, TE occurs when there’s a change in the number of hair follicles growing. If the number of hair follicles producing hair significantly decreases for any reason during the resting (telogen) phase, there will be a significant increase in dormant hair follicles. This is known as TE hair loss, and it can be more severe in some areas of the scalp than others. It’s uncommon to have hairline recession with TE hair loss, except in a few rare chronic cases.

The hairs that begin to shed are typically telogen hairs, which can be identified by a small bulb of keratin on the root end. People with TE never completely lose all their hair, but the hair can be noticeably thin in severe cases. TE is often limited to the scalp and is reversible. The hair follicles are not permanently or irreversibly affected; there are just more hair follicles in a resting state than there should normally be.

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Environmental conditions, stress, diet, acute or chronic illness, nutritional deficiencies and scalp infections can also cause hair loss, but these are not clinically related to seasonal changes. Because “summer is coming,” you might find your hair density is less during the summer season, but don’t fret: The seasons will change.

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Summertime Hair Loss: It’s Real originally appeared on usnews.com