A good, hearty laugh relieves physical tension and stress, leaving your muscles relaxed for up to 45 minutes after. Laughter boosts the immune system. Laughter decreases stress hormones and increases immune cells and infection-fighting antibodies, thus improving your resistance to disease.Dr. Fred Clary, founder of Functional Analysis Chiropractic Technique and lifting/life coach/ gym-chalk covered philosopher opens a conversation on how laughter increases your immune system.