Fatigue is not just "muscle failure." It is largely Heat Failure. When you exercise, your core body temperature rises. At a certain point, an enzyme called Pyruvate Kinase (critical for muscle contraction) stops working efficiently because it is heat-sensitive. Your brain effectively says, "We are too hot, shut down the engine." Stanford researchers (Dr. Craig Heller) discovered a "backdoor" to the body's thermostat: Glabrous Skin. The palms of your hands, the soles of your feet, and the upper face contain special blood vessels called Arteriovenous Anastomoses (AVAs). These are direct connections between arteries and veins, acting as the body's radiator. The Hack: If you cool your palms (not freeze them, just cool them) between sets of exercise, you cool the blood passing through the AVAs. This cooled blood travels back to the heart and core, lowering your internal temperature instantly. The Result: In studies, athletes who used palmar cooling were able to match or exceed the volume improvements seen in subjects using anabolic steroids. They went from doing 10 pull-ups to 600 pull-ups over several weeks, simply because they prevented the "heat shutdown." ⚡ Vital Advice: The "Bottle" Technique: You don't need the $2,000 Stanford machine. Freeze a water bottle (halfway). Bring it to the gym. Between heavy sets (squats, bench), hold the cold bottle in your palms for 60-90 seconds. Your next set will feel surprisingly easy. You are chemically resetting your fatigue.