Travel related changes in performance and physiological markers: the effects of eastward travel on female basketball players.
Ozan Atalağ, Lincoln Gotshalk
PMID 37266356WHAT IT FOUND
Female basketball players on a heavy eastward travel schedule showed increased belly fat, higher resting heart rate and blood pressure, doubled cortisol, and weaker hamstrings compared to non-athlete peers.
These changes occurred despite no change in total body fat.
Key findings
01Players showed significant increases in visceral trunk fat, waist circumference, and waist-to-hip ratio, while total body fat percentage remained unchanged.
02Resting heart rate, systolic and diastolic blood pressure, and salivary cortisol levels all rose significantly in the players from pre-season to post-season.
03Maximal knee flexion strength decreased significantly in both legs, reducing the hamstring-to-quadriceps strength ratio, while vertical jump height showed a non-significant decline.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study did not measure acute responses to single trips, only the cumulative effect of the season, making it difficult to isolate the specific impact of jet lag from other stressors like training load or game losses. Control groups were not perfectly matched; they had different course loads and likely different psychological stressors than the athletes. Sleep and nutrition habits were self-reported and not objectively verified, so poor sleep or diet could have contributed to the cortisol and body composition changes. The sample size is small and limited to female collegiate basketball players, restricting generalizability to male athletes or other sports.
Declared interests
The authors declared no conflicts of interest, and the research received no external funding.
The easy way to misread this
Do not attribute these physiological changes solely to jet lag or travel. The study did not control for training load, game losses, or sleep quality, so the observed increases in cortisol and body fat could be driven by general stress or overtraining rather than time zone shifts.