Teams fly across time zones constantly and the advice they follow is plentiful: light exposure, melatonin, nap schedules, meal timing, sedatives, stimulants. A systematic review set out to evaluate all of it, pharmacological and non-pharmacological alike, in athlete populations after long-haul travel or laboratory . The interesting result is not which intervention won. It is how much evidence turned up.
Almost none for , and thin evidence for . Twenty-two articles met the criteria, eight non-randomized and fourteen randomized trials. No relevant travel fatigue papers were found at all, so one of the two conditions the review set out to cover had no direct trials. For jet lag, only 12 athlete-specific studies were available, which is why the search had to be widened to healthy populations.
Athletes cross time zones constantly and there is no shortage of guidance on coping with it. This review investigated the management of travel fatigue and jet lag in athlete populations. It evaluated non-pharmacological interventions, meaning exercise, sleep, light and nutrition, alongside pharmacological ones including melatonin, sedatives, stimulants, melatonin analogues, glucocorticoids and antihistamines.
Eligibility was deliberately broad. Randomized controlled trials and non-randomized studies, experimental and observational, were included provided they explored interventions after actual travel-based or laboratory-based phase shifts. Studies had to involve athletes, except where an intervention yielded no athlete studies at all, in which case the search was expanded to healthy populations.
Electronic searches covered PubMed, MEDLINE, CINAHL, Google Scholar and SPORTDiscus from inception to March 2019. Every included article was assessed for risk of bias, methodological quality, level of evidence and , which is the apparatus a review needs to say anything about confidence rather than just volume.
Twenty-two articles were included, eight non-randomized and fourteen randomized. Then the gap: no relevant travel fatigue papers were found, and for jet lag only 12 athlete-specific studies were available. One of the two conditions the review set out to cover has no direct trials in athletes, and the other has very few. That is a statement about the state of a field rather than about what works.
wat. Searching five databases for trials on managing athlete travel fatigue returned nothing, and jet lag had only twelve athlete-specific studies.
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An empty shelf is a finding. Practitioners advise athletes on travel fatigue routinely, and the review shows that advice is not resting on trials in athletes because there are none.
How do we know?
Janse van Rensburg and colleagues searched PubMed, MEDLINE, CINAHL, Google Scholar and SPORTDiscus from inception to March 2019, for trials of interventions after real or laboratory phase shifts. Risk of bias and quality of evidence were assessed.
What is still unknown
A review can only report what exists, so this characterizes a literature rather than answering the clinical question. Where athlete studies were missing the search was expanded to healthy populations, which weakens the applicability further.
Learn something?
Where to next
Why is exhaustion from a long flight not always jet lag?flying
Does every athlete need exactly nine hours of sleep?sleep
Does the direction you flew in from change how you play at home?jet lag