REVEALED: The real reason behind Roger Federer's terrible US Open match

Roger Federer was knocked out of the US Open in the fourth round by world number 55 John Millman. The 37-year-old Swiss had prioritized winning a sixth title at Flushing Meadows but was beaten 3-6 7-5 7-6  (9-7) 7-6 (7-3) in three hours 35 minutes. Federer’s loss was one of the biggest upsets of the year. In an interview to The New York Times, Lacy Alexander, an associate professor of kinesiology for the Pennsylvania State University, said: "When we exercise, our primary means of cooling ourselves off is to sweat. For every gram of sweat we evaporate, we liberate heat. It provides no cooling capacity for the body." “Millman played very aggressive tennis, and Federer could not cope with the Australian. In order to win that match, the Basel native needed to play his best tennis. That high level of training on a day-to-day basis imparts a degree of heat acclimation just because of high fitness,” Alexander added. Mr. Crouch said: “At 10:51 p.m. the heat index was 95 — that’s pretty incredible. That’s a hot heat index in the middle of the summer, in the middle of the day, for New York."

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