Pilot study: physiological evidence that heat reduces pain and muscle damage in delayed-onset muscle soreness

SUMMARY: Aim: To determine if heat applied after strenuous exercise reduces soreness and/or muscle damage. Methods: Self-reported soreness and blood biomarkers were measured in 20 subjects over 72 h after biceps exercise. Heat was applied both immediately and 24 h after exercise, or never (control). Results: Muscle soreness was lower in groups with more heat applied. Skin temperature and some biomarker analytes (granulocytes and mid-size white cells) support a hypothesis of less pain and faster healing in muscles when heat is applied after exercise. Ultrasound data showed less fascial swelling in groups with heat applied compared with controls. Conclusion: Data suggest that heat applied immediately and/or 24 h after exercise reduces muscle soreness and accelerates the healing process. A larger group of subjects is needed to draw better conclusions.