Short-term resource allocation during extensive athletic competition

Daniel P. Longman*, Sean P. Prall, Eric C. Shattuck, Ian D. Stephen, Jay T. Stock, Jonathan C.K. Wells, Michael P. Muehlenbein

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    18 Citations (Scopus)
    25 Downloads (Pure)


    Objectives: Following predictions from life history theory, we sought to identify acute trade-offs between reproductive effort (as measured by psychological arousal) and somatic maintenance (via functional measures of innate immunity) during conditions of severe energetic imbalance. Methods: Sixty-six male ultramarathon runners (ages 20 to 37 years) were sampled before and after a lengthy race. Saliva and sera were collected for testosterone and immunological analyses (hemolytic complement activity and bacterial killing ability). Lean body mass was assessed by bioelectrical impedance, and libido was measured using a slideshow of arousing and neutral images. Results: Following predictions, there was a significant decrease in salivary testosterone levels (109.59 pg/mL versus 97.61 pg/mL, P <.001) and arousal scores in response to provocative images (5.40 versus 4.89, P =.001) between prerace and postrace time points. Additionally, participant bacterial killing ability (P =.035) and hemolytic complement activity (P =.021) increased between prerace and postrace. Conclusions: Decreased libido and testosterone with concomitant heightened innate immune responses suggest a shift in energetic priorities away from reproduction and toward maintenance/defense during a period of energetic stress.

    Original languageEnglish
    Article numbere23052
    Pages (from-to)1-11
    Number of pages11
    JournalAmerican Journal of Human Biology
    Issue number1
    Early online date10 Oct 2017
    Publication statusPublished - 1 Jan 2018

    Bibliographical note

    Copyright the Author(s) 2017. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.


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