Exercise and Susceptibility to Infection:
The J-Curve Model
The relationship between exercise and infection risk follows what we call the "J-Curve" hypothesis. This model shows how different exercise intensities affect our immune system and, consequently, our susceptibility to infections.
NoteThe J-Curve gets its name from the shape of the graph when plotting exercise intensity against infection risk - it looks like the letter "J"!
Breaking Down the J-Curve:
- Moderate Exercise (Sweet Spot)
- Reduces risk of infection
- Enhances immune function
- Typically includes activities at 40-60% of maximum capacity
- Duration: 30-60 minutes per session
- Sedentary Lifestyle (Base of the J)
- Slightly elevated infection risk
- Reduced immune function
- Characterized by minimal physical activity
- High-Intensity Exercise (Top of the J)
- Significantly increased infection risk
- Temporary immune suppression
- Particularly risky after prolonged, intense sessions
- Examples: marathon running, intense training camps
After intense exercise, there's a period called the "open window" where we're more susceptible to infections.
TipAthletes should be extra careful about exposure to pathogens in the 3-72 hours following intense exercise sessions.
Key characteristics:
- Duration: 3-72 hours post-exercise
- Immune system function is temporarily decreased
- Higher risk of Upper Respiratory Tract Infections (URTIs)
Factors Affecting Infection Risk
Internal Factors:
- Training status
- Recovery state
- Sleep quality
