How Science and Materials Keep Winter Olympians Warm

Winter Olympians frequently compete in freezing conditions. The human body's physiology and modern advances in materials science work together to help them stay warm and perform at their peak. This year, the Winter Olympic and Paralympic Games are hosted by Milan and Cortina d'Ampezzo, Italy. Weather forecasts predict temperatures between the upper 30s and mid-40s Fahrenheit (1 to 10 degrees Celsius). These temperatures are warmer than typical expectations for a winter mountain setting. For athletes, this presents a unique challenge. The conditions are warm enough to require adjustments to competition equipment, yet still cold enough to affect the physiology of athletes and spectators.

As experts in biological anthropology and materials science, we examine how the body adapts to different environments and how engineered materials can enhance performance and address health issues. Both biological adaptation and material innovation will be crucial for athletes aiming for their best performances in Italy. Athletes participating in outdoor events are accustomed to cold and unpredictable weather, which is an inherent part of their sports. While extreme cold is unlikely this year, the outdoor conditions will still influence their performance.

One significant concern is dehydration. In cold weather, sweating is usually less frequent and intense, making dehydration less noticeable. However, cold air typically has lower relative humidity. This dry air forces the body to use its own water to humidify the air before it reaches the sensitive lung tissue. Athletes breathing heavily during competition lose more body water through this process than they would in more temperate climates. Additionally, the body's natural response to cold is to constrict blood vessels. This narrowing helps conserve heat by reducing blood flow to the skin, but it also pushes more fluid out of the circulatory system and toward the kidneys. This process increases urine output, contributing further to fluid loss.

Although athletes may not sweat as profusely as in warm conditions, they still sweat. They wear specialized clothing designed for performance and cold protection. The combination of layered clothing and the body's own heat generated from intense activity can create a hot, damp environment between the skin and the inner fabric. This moist layer is not just another source of water loss; it can also become a problem for athletes who compete in multiple rounds, such as in skiing or snowboarding heats. These athletes work up a sweat during their run and then must wait for their next turn. During this waiting period, the damp layer of sweat can make them more susceptible to losing body heat and increase the risk of cold injuries like frostbite or hypothermia. Therefore, staying warm between competition rounds is essential.

Staying warm is fundamentally about the selection and construction of materials. Many apparel manufacturers use a three-layer system to keep wearers warm, dry, and comfortable. The base layer is in direct contact with the skin. It is typically made from a moisture-wicking synthetic fabric like nylon or a natural fabric like wool. Its primary job is to pull sweat away from the body to keep the skin dry. The second layer is for insulation. This layer is generally porous, designed to trap warm air generated by the body and slow down heat loss. Excellent insulating materials include down and fleece.

The final, outer layer provides protection from the elements. It needs to be both waterproof and breathable. This balance keeps the inner insulating layers dry from outside precipitation while allowing sweat vapor to escape. Lightweight, durable, and moisture-resistant materials like polyester and acrylic are common choices for this layer.

Athletic gear can be customized for specific needs. For instance, the synthetic fabrics used in the base layer are versatile. Materials scientists can engineer new properties into them, such as adding specific coatings to nylon to provide wind and water resistance. Often, both the synthetic fibers and their coatings are composed of polymers. Polymers are long chains of molecules. They can be human-made and petroleum-based, like the polyethylene in trash bags, polyester, or Teflon. However, polymers also exist in nature; examples include DNA and the proteins in your body. Beyond polymer technology, conventional options like battery-powered heated jackets are also available for warmth.

Another innovative category involves smart materials known as phase change materials. These are made from polymers and composite materials. They function by passively regulating body temperature: they absorb excess body heat when an athlete gets too warm and release stored heat back to the body when needed. These materials work by transitioning between solid and liquid states in response to the body's natural temperature cues. Their primary role is not so much to warm you up as to maintain a balanced, stable temperature.

While not yet standard in elite athletic wear, organizations like NASA have experimented with phase change materials for decades. The technology is already used in many commercial products, such as cooling bed linens and towels, which are designed to prevent overheating.

Athletes are not the only ones at risk from cold conditions at the Winter Games. While most viewers will watch from the comfort of heated indoor spaces, thousands of spectators, volunteers, and support staff will be outdoors for extended periods. Unlike the athletes, these individuals do not have the benefit of generating significant internal heat through physical exercise. Consequently, non-athletes at the events may be at greater risk in the cold.

If you plan to attend or work at an outdoor winter event, it is important to stay hydrated by drinking more water than usual and planning bathroom breaks accordingly. Dressing in several removable layers allows for better temperature control. Pay special attention to protecting vulnerable body parts like the hands, feet, and nose. The body activates various metabolic responses in colder temperatures. One familiar response is shivering, which involves small, rapid muscle contractions that generate heat. Additionally, a specialized type of body fat called brown adipose tissue becomes active, producing heat instead of storing energy.

Both shivering and brown fat activity burn extra calories. This means you may feel hungrier if you spend a long time in the cold. Trips indoors for food or to use restrooms also provide welcome opportunities to warm up, particularly your extremities. It is easy to view Olympians as exceptional athletes battling against nature's cold. However, a combination of the human body's remarkable physiological adaptations and the impressive technological advances in winter apparel science will work together to keep these athletes warm and performing at their highest level.