Social & Preventive Medicine Air, Light, Sound, Housing, Radiation, Waste Disposal 4f260148 McArdle's Maximum Allowable sweat rate:- A < 4.5 litre/4 hours B < 3.0 litre/4 hours C < 3.5 litre/4 hours D < 5.0 litre/4 hours High-Yield Explanation McArdle's Index: - It is an index of thermal comfo. Max P4SR (Predictable 4 hour sweat rate): <4.5lit/4hours. Beyond this death of person is imminent.