The invention discloses a dumbbell. The dumbbell comprises a dumbbell rod and a dumbbell block, wherein the dumbbell rod comprises an inner ring rod and an outer ring rod; a plurality of through holes are formed in the surfaces of the inner ring rod and the outer ring rod; a heat dissipation ventilation chamber is formed between the inner ring rod and the outer ring rod; an antibacterial bag is mounted in an inner chamber of the inner ring rod; mini-type fans are further mounted at two ends of the dumbbell rod; and the mini-type fans are used for blowing air into the inner chamber of the inner ring rod.