Sperm counts and reproductive hormones in male marathoners and lean controls

Bagatell, Carrie J.; Bremner, William J.

doi:10.1016/s0015-0282(16)53465-7

Cited by 75 publications

(51 citation statements)

References 21 publications

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“…Although human males do not face the same energetic challenges as females (i.e., gametogenesis, gestation, and lactation), and energetic investment in spermatogenesis is minimal (Bagatell & Bremner, 1990; Elias, 1992), mating effort is still metabolically demanding. Energy costs include competition and mate attraction, as well as protection of and provisioning for mates and offspring (Muehlenbein & Bribiescas, 2005).…”

Section: Discussionmentioning

confidence: 99%

Short‐term resource allocation during extensive athletic competition

Longman

Prall

Shattuck

et al. 2017

American J Hum Biol

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ObjectivesFollowing 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.MethodsSixty‐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.ResultsFollowing 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.ConclusionsDecreased 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.

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Section: Discussionmentioning

confidence: 99%

Short‐term resource allocation during extensive athletic competition

Longman

Prall

Shattuck

et al. 2017

American J Hum Biol

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“…With the exception of significantly higher FSH levels in some athletes compared to sedentary controls, no differences were noted in testosterone, LH, sperm count, or sperm morphology. In a similar investigation, a comparison of reproductive parameters between male marathon runners and sedentary controls revealed that with the exception of bioactive LH levels, there were no significant differences in LH, FSH, free and total testosterone, or sperm count (Bagatell and Bremner, 1990). Ayers et al (1985) observed declines in testosterone levels in marathon runners; however, androgen levels remained well within the range of clinical acceptability.…”

Section: Energetic Expenditurementioning

confidence: 92%

Reproductive ecology and life history of the human male

Bribiescas

2001

Am. J. Phys. Anthropol.

210

117

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Until recently, the reproductive ecology of human males has not been extensively investigated, primarily as a result of the need for a theoretical framework based on the reproductive constraints and energetics of mammalian males. More specifically, male reproductive ecology has necessitated an integrative interpretation of clinical and anthropological data based on the premise that the evolution of human male life histories has involved selection for physiological mechanisms aimed at optimizing trade-offs between survivorship and reproductive effort. This paper attempts to address this gap in our understanding by presenting the current state of male reproductive ecology, including physiologic data from clinical and anthropological investigations as well as recent theoretical developments. Recent investigations outlining population variation in reproductive endocrine function are discussed within the context of potential sources of variation, including energetic expediture, caloric intake, and developmental canalization during adolescence. Additional summaries of male senescence and behavior are presented to provide a complete overview of male life history. Implications of recent anthropological data on contemporary health issues such as prostate cancer and the development of a male contraceptive are also discussed. Finally, several theories are presented that may contribute to our understanding of the evolution of male life histories and reproductive ecology, including theoretical suggestions involving the role of competition, mate choosiness, and potential constraints on male insemination ability, as well as a theory suggesting that male reproductive ecology may be best understood by analyzing energetic allocation decisions between differing somatic tissues that may be indicative of the competing needs for optimizing survivorship and reproductive effort. Directions for future research are finally considered.

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“…Some evidence indicates a role for aerobic physical activity in SHBG production, at least in men. SHBG concentrations have been observed to increase acutely with such exercises as cycle ergometry, and with longer-term endurance training (38)(39)(40)(41), although some reports involving endurance-trained younger men have not confirmed this effect (18,21,37,42). As SHBG concentrations vary inversely with circulating insulin (43), a plausible explanation for greater SHBG values in trained older men could be attenuation of agerelated insulin-resistance.…”

Section: Journal Of Endocrinology (1998) 138mentioning

confidence: 99%

“…Several authors have reported lower concentrations of both total testosterone (17,18) and free testosterone (19,20) in young endurance-trained men compared with age-matched 'sedentary' controls, whereas others have observed no effect of endurance exercise on total testosterone concentrations (21,22). Even if habitual endurance activity were to improve IGF-I production, an exercise-dependent attenuation of gonadal function might negate any potential benefits of the former on body composition.…”

Section: Introductionmentioning

confidence: 99%

Relationship of chronic endurance exercise to the somatotropic and sex hormone status of older men

Cooper

Taaffe

Guido

et al. 1998

European Journal of Endocrinology

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To investigate putative abrogating effects of habitual endurance exercise on age-related changes in endocrine function and body composition, we compared insulin-like growth factor-I (IGF-I), sex hormonal status and body composition in 15 Masters runners and 15 minimally exercising men (MEM) aged 60-70 years. A higher maximal oxygen uptake (VO 2 max.) in the runners (41.4 Ϯ 1.6 compared with 27.3 Ϯ 1.4 ml/kg/min, P ¼ 0.0001; mean Ϯ S.E.M.) reflected our group allocations. Analysis of body composition and bone mineral density (BMD) by dual energy X-ray absorptiometry showed no group differences in lean tissue mass or in regional or whole body BMD, but MEM were heavier, reflecting greater adiposity. Of nine muscle groups tested, only quadriceps strength differed significantly, being greater in runners (60.3 Ϯ 2.8 compared with 51.1 Ϯ 2.3 kg, P ¼ 0.02). Total IGF-I (129 Ϯ 10 compared with 124 Ϯ 11 ng/ml, P ¼ 0.72) and IGF-binding protein-3 (2854 Ϯ 94 compared with 2623 Ϯ 128 ng/ml, P ¼ 0.16), were similarly depressed compared with young adult norms in both groups. There was no relationship between total or bioavailable IGF-I and any body composition, BMD or muscle strength variable. In the runners, concentrations of total testosterone (19.1 Ϯ 0.8 compared with 15.0 Ϯ 0.9 nmol/l, P ¼ 0.002) and sex hormone binding globulin (SHBG) (124.4 Ϯ 21.6 compared with 67.7 Ϯ 11.6 nmol/l, P ¼ 0.03) were significantly greater, but the free androgen index was significantly lower (20.7 Ϯ 2.7 compared with 31.4 Ϯ 4.1, P ¼ 0.04). Directly measured free testosterone, however, was similar between the runners and MEM (47.9 Ϯ 1.8 compared with 47.1 Ϯ 2.0 nmol/l, P ¼ 0.80). Therefore the group differences in total testosterone and free androgen index were due to their different SHBG concentrations. Although estrone concentration was higher in MEM (85.1 Ϯ 5.2 compared with 108 Ϯ 6.7 pmol/l, P ¼ 0.03), estradiol concentration was similar between groups (73.0 Ϯ 6.3 compared with 81.8 Ϯ 8.0 pmol/l, P ¼ 0.18), indicating that estrogens were not responsible for the increased SHBG in runners. These results indicate that even high levels of regular endurance exercise do not prevent the decline in the somatotropic axis that occurs with aging. Furthermore, the somatic effects of exercise in older men (reduced adiposity and increased regional muscle strength) occurred independently of somatotropic or androgen status. Although habitual exercise does not influence free testosterone concentrations in older men, it appears to enhance the age-associated increase in SHBG synthesis.

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Sperm counts and reproductive hormones in male marathoners and lean controls

Cited by 75 publications

References 21 publications

Short‐term resource allocation during extensive athletic competition

Short‐term resource allocation during extensive athletic competition

Reproductive ecology and life history of the human male

Relationship of chronic endurance exercise to the somatotropic and sex hormone status of older men

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