024 - Are we sacrificing firefighter wellness with outdated shift patterns just because “it has always been done this way”?
48 On, 96 Off: Does Your Shift Schedule Build or Break Your Readiness?
Not all shifts are created equal.
For firefighters, the job doesn't just demand strength, endurance, and grit—it demands recovery. This study compared nearly 900 male firefighters across two common schedules:
48/96: 48 hours on, 96 off
4’s and 6’s: The traditional rotating day/night split
The goal? Measure how these schedules impact body composition, muscular fitness, cardio endurance, and flexibility—in other words, performance that matters under pressure.
What the Data Showed
Firefighters on the 48/96 schedule had:
Lower BMI
Lower body fat %
Greater trunk flexibility
VO₂max and strength outcomes slightly favored 48/96, but didn’t reach statistical significance.
Bottom line: While the health differences weren’t massive, the trend favors the 48/96 schedule, especially in areas that relate to injury prevention and long-term sustainability.
What This Means for Tactical Professionals
The schedule you work on directly impacts how well your body holds up, and how quickly it breaks down.
This isn’t about minor differences in charts. It’s about whether your shift structure supports or sabotages your fitness, recovery, and longevity in the field.
Tactical Applications
1. Audit Your Shift Structure
If you're running the 4’s and 6’s, it’s time to evaluate how it affects your crew’s recovery and operational capacity.
Start with internal data: sleep patterns, fitness trends, injury rates.
2. Use the Off-Time Wisely
The 96-hour recovery window is only useful if it’s optimized. Hydrate. Move. Sleep. Restore.
Train smart—don’t cram max effort sessions into already-depleted recovery windows.
3. Implement Targeted Wellness Programs
Focus on flexibility, core strength, and cardio—these were the categories that responded best.
Leverage periodic health assessments (VO₂max, BF%, flexibility) to create individualized performance plans.
Stay Thick.
Garrett LR, Harveson AT, Ayars C. Shift schedule effects on firefighter health and fitness. Work. 2024;78(4):1115-1122. doi:10.3233/WOR-230388