Short Wave

How do extreme G-forces affect Olympic bobsledders?

February 4, 2026

Key Takeaways Copied to clipboard!

  • The condition experienced by sliding sports athletes, characterized by dizziness, nausea, and exhaustion following high G-force runs, is termed "sledhead" and is linked to concussions and subconcussions. 
  • Athletes often conceal symptoms of sledhead from coaches and medical staff due to fear of being excluded from training or the team, highlighting a systemic barrier to addressing brain health. 
  • Protecting athletes' brains from the effects of high G-forces and vibration may require structural changes to the sport itself, rather than relying solely on athletes to report injuries, suggesting the need for objective measurement tools like exposure sensors. 

Segments

Introduction to Sliding Sports
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(00:00:28)
  • Key Takeaway: Sliding sports like bobsled, luge, and skeleton involve speeds up to 90 mph, creating intense physical stress on athletes.
  • Summary: The Winter Olympics feature sliding sports where athletes reach speeds of 80 to 90 miles per hour. Former skeleton athlete Aaliyah Snyder described the experience as feeling like flying on good days and a car crash on bad days. Symptoms following runs, including shakiness and disorientation, were initially dismissed as normal.
Defining and Experiencing Sledhead
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(00:01:31)
  • Key Takeaway: Sledhead is the term for symptoms like dizziness, nausea, and cognitive problems following high G-force runs, which can lead to accumulated brain damage.
  • Summary: Sledhead encompasses dizziness, nausea, exhaustion, and cognitive issues resulting from the brain-rattling runs. Aaliyah Snyder experienced accumulating symptoms that ultimately led to her medical retirement after accumulating around six concussions. Athletes often hide these symptoms for fear of being overlooked for the team.
Neuropsychology Research Focus
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(00:02:27)
  • Key Takeaway: Neuropsychologists like Aaliyah Snyder are focusing research on sliding athletes to understand the medical impact of sledhead.
  • Summary: Aaliyah Snyder transitioned into neuropsychology to research the effects of sliding sports on athletes’ brains. Researchers like Peter McCarthy and Aaliyah Snyder are working to build the body of scientific work currently lacking in this area. Fear of exclusion prevents athletes from reporting symptoms to coaches or medical teams.
Understanding Extreme G-Forces
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(00:04:55)
  • Key Takeaway: Sliding sports expose athletes to G-forces exceeding 5 Gs, causing the soft brain tissue to impact the accelerating skull.
  • Summary: Normal Earth gravity is 1G, but roller coasters and bobsledding can generate over 5 Gs on tight turns. This intense force causes the brain to ‘squidge’ against the skull, and stretching forces affect the brain tethered at the brainstem. Helmets protect the skull but not the internal movement causing concussions or sub-concussive impacts.
Helmet Sensor Data Collection
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(00:06:38)
  • Key Takeaway: Sensors placed in helmets measure low-frequency vibrations (below 50 hertz) that transmit movement through the system to the brain.
  • Summary: Peter McCarthy developed helmet sensors to study the vibration athletes experience, measuring three axes of movement. The majority of recorded frequencies are below 50 hertz (50 shakes per second). Lower frequencies allow more movement to transmit through the system to the athlete’s head.
Autonomic Nervous System Impact
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(00:09:04)
  • Key Takeaway: Repeated subconcussive injury can reduce an athlete’s tolerance to G-force stress by causing a subtle disconnect in the autonomic nervous system’s regulation.
  • Summary: Following a major injury, some bobsled athletes show reduced tolerance to high G-force curves, leading to headaches, fatigue, and attentional difficulties. The autonomic nervous system, which regulates automatic body functions like heart rate and pupil size, experiences wear and tear on its accuracy due to repeated stressors. Recovery requires addressing cognitive, emotional, and physiological inputs, not just relying on a ‘push-through-it’ mindset.
Recommendations for Governing Bodies
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(00:13:01)
  • Key Takeaway: Governing bodies must implement objective measurement systems, like exposure meters, to enforce rest periods and protect athletes who will otherwise compete while injured.
  • Summary: Athletes are highly motivated to compete and will often play through injury, making self-reporting unreliable for safety. An objective measurement system, such as an exposure meter, is necessary to mandate rest when an athlete has reached a safe limit for the week. Implementing such a structure is crucial for protecting athlete well-being.