The clearest concern is repeated exposure rather than one isolated flight. The report says journeys exceeding 2,800 miles, crossing three time zones and involving up to six hours of flying can combine fatigue, disrupted sleep and operational stress.
That burden matters in a knockout tournament. A team may have less time to train, recover and prepare for its next opponent, while staff must manage players arriving in different physical and mental states.
The study reportedly drew on feedback from medical and performance professionals working in North American football. Its central warning is that travel should be measured across the season, rather than treated as a series of unrelated trips.
Time-zone changes can affect when players sleep, eat and train. Even without an injury, disrupted rest can reduce sharpness and make recovery harder between matches.
The report says the adjustment is not purely physiological. Behavioural, psychological and operational factors also raise the stress surrounding long-distance travel. That places greater responsibility on coaches, analysts, medical teams and operations staff to build a consistent tournament routine.
The recommended response is practical:
The teams that handle those details best could gain an edge when margins are narrow and fatigue accumulates. As World Cup camps take shape, the next storyline will be whether travel management becomes as carefully planned as set pieces, substitutions and squad rotation.