A study of police officers in Britain found 60 seconds of all-out physical exertion in a threatening situation seriously damaged the memory of the incident. Dr. Lorraine Hope of the University of Portsmouth, England, found police officers, witnesses and victims of crime suffer loss of memory, recognition and awareness of their environment if they have had to use bursts of physical energy in a combative encounter. Hope said the 60 seconds of all-out exertion could seriously impair the ability of police officers -- even those in top condition -- to remember details of the incident or even identify the person who was involved. The findings were a stark warning to police officers, police chiefs and the courts, Hope said. \"Police officers are often expected to remember in detail who said what and how many blows were received or given in the midst of physical struggle or shortly afterwards. The results of our tests indicate it may be very difficult for them to do this. As exhaustion takes over, cognitive resources tend to diminish,\" Hope said in a statement. \"The legal system puts a great deal of emphasis on witness accounts, particularly those of professional witnesses like police officers. Investigators and courts need to understand that an officer who cannot provide details about an encounter where physical exertion has played a role is not necessarily being deceptive or uncooperative.\" The findings were published in the journal Psychological Science.