Curly Hair Keeps Heads Cooler Than Straight Locks According to Science

The Great Hair Debate: Do Straight or Curly Locks Keep You Cooler?

The debate over whether straight or curly hair is better at keeping people cool in hot weather has raged on for years. Both hair types have their ardent defenders and detractors. But what does the science say about which style truly keeps your head cooler?

A recent study shed new light on this age-old question. Researchers found that people with curly hair tend to stay cooler than those with straight strands or no hair at all. The corkscrew shape of curls creates more air pockets near the scalp, providing insulation from heat.

The Science Behind Curly Hair's Cooling Effects

To understand why curly hair keeps heads cooler, you first need to know a bit about how hair works. Each strand is made up of the protein keratin arranged in a helical structure. This spring-like shape makes hair elastic and bendable, while still maintaining strength.

In curly hair, the keratin fibers twist more tightly together. This contraction forms thick locks that curve around on themselves, creating a series of nooks and crannies between each curl. It's in these spaces that cooler air becomes trapped, forming a barrier against heat.

By comparison, straight hair lacks these air pockets. The keratin fibers run relatively parallel to each other, allowing heat to penetrate down to the scalp. People with straight hair tend to feel hotter faster when temperatures rise.

Other Factors That Impact Hair's Cooling Ability

While curl pattern plays a key role, other variables also affect how effectively hair shields against heat. These include:

• Strand thickness - Thicker strands, whether straight or curly, hold more insulating air than fine hair.
• Hair length - Longer hair means more layers to block heat. Short hair provides less protection.
• Hair density - More hairs per square inch creates tighter curly patterns and smaller air chambers that keep out heat.
• Hair health - Dry, damaged hair is more porous allowing heat to access the scalp easier.
• Scalp health - A dry scalp loses heat faster leading to a hotter head.

Straight Hair Isn't Necessarily a Disadvantage

Does this mean people with straight locks are doomed to swelter in the summer sun? Not necessarily. Straight hair has some cooling properties too, albeit to a lesser degree than curls.

For example, having straight but thicker or longer hair still provides insulating air pockets close to the head. The looser structure also allows more airflow to lift heat up and away from the scalp. Meanwhile, short, fine straight hair offers the least protection.

Study Shows Curly Hair Keeps Heads Cooler

In 2022, researchers at Nanjing University of Information and Science Technology in China performed an interesting experiment on hair types and heat resistance. They modeled how effectively curly, straight, and no hair (bald) conditionskept scalps coolunder solar radiation.

Using computer simulations, the team calculated heat flux, or the rate of heat energy transfered to the scalp surface. They tested curly and straight hair at lengths of 1 cm and 10 cm. The bald scalp acted as an experimental control.

Key Findings of the Cooling Study

The researchers found clear evidence that curly hair provided more protection from heat than straight locks or baldness. Some key findings included:

• Curly hair at 10 cm length reduced scalp heat flux by 34% compared to the bald scalp.
• Straight hair at 10 cm length lowered heat flux by only 10% relative to having no hair.
• Short curly hair still decreased scalp heat flux by 24% versus baldness.
• At 1 cm, straight hair had no measurable impact on heat flux versus a bald scalp.

Based on this model, the study authors concluded that curly hair keeps scalps much cooler tha straight hair when exposed to hot, sunny conditions. The tighter the curl pattern, the more heat is blocked from penetrating to the head.

Why This Research Matters

These findings add scientific evidence to the idea that curlier hair helps retain heat in colder climates, while promoting cooling when temperatures rise. This may partially explain why curly locks are more prevalent among people whose ancestors evolved in hot, tropical regions.

The research also underscores how hair structure serves protective purposes beyond aesthetics. As the study authors wrote: "The biological functions of various hairstyles deserve further attention from the public and researchers."

Tips for Keeping Your Head Cooler

While you can't change your genetically-programmed hair texture, people with straight, curlyand wavy hair can use other tricks to keep cooler in summer.

For Straight Hair

• Grow hair longer to create more insulating layers.
• Add volume at the roots to trap air.
• Apply UV protection to avoid damage from sun exposure.
• Consider thermal protecting straightening processes.

For Curly Hair

• Define curls to maximize air pockets.
• Use lightweight products to avoid weighing hair down.
• Sleep with hair gathered up to maintain curl formation.
• Resist combing curls for volume and structure.

For Any Hair

• Wear hats, scarves or protective styles to shield hair from sun.
• Mist hair with cool water to dissipate heat.
• Apply cooling gels or serums to the scalp.
• Stay hydrated and use scalp sunscreens as needed.

While the curly versus straight debate wages on, science shows tigther coils have a cooling advantage. But with a few tweaks, straight hair can better shield against summer heat too.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.