180206-N-UJ980-060 SAN DIEGO (Feb. 6, 2018) Capt. Joel Roos, Naval Medical Center San Diego (NMCSD) commanding officer, second from right,visits the Naval Health Research Center’s (NHRC) environmental chamber in the Warfighter Performance Laboratory. During the visit, researchers discussed how the chamber can be used to study the physiological impact of extreme temperatures and improve warfighter health and performance. (U.S. Navy photo by Regena Kowitz/Released)