Hesz also won six medals at the ICF Canoe Sprint World Championships with two golds (K-1 10000 m: 1966, K-1 4 x 500 m: 1971), a silver (K-1 4 x 500 m: 1966), and three bronzes (K-1 500 m: 1971, K-1 10000 m: 1963, K-1 4 x 500 m: 1970).