Hein graduated in 1984 in Human Movement Sciences at VU Amsterdam specialized in exercise physiology. He worked for TNO (Dutch Organisation of Applied Scientific Research) for 26 years and occupied an endowed chair in Thermal Physiology at VU since 2003. Since 2016 he is full professor in (environmental) exercise physiology, heads the physiology group and is program director of the master Human Movement Sciences.
He publishes mainly on how humans cope with heat and cold and engages in the public debate on these topics. He loves to play basketbal and ride a bike.