Trained and untrained males show reliable salivary testosterone responses to a physical stimulus, but not a psychological stimulus

Modest Exercise-Induced Increases in Testosterone Concentration Are Not Associated with Mating Strategy Change in Healthy Young Men

Research has demonstrated that increases in testosterone (T) concentration can affect the expression of behaviours and preferences that are typical of high mating effort. However, little research has considered whether such T increases affect mating strategy more generally and whether this is achievable using a physical intervention. In this pilot study, we examined whether exercise-induced changes in T covary with, or predict, changes in male mating strategy. Healthy young men (N = 94) completed a measure of short- and long-term relationship preference, before and after a series of short cycling sprints. Salivary T was measured pre- and post-exercise, along with salivary cortisol (C), which is known to moderate some behavioural effects of T. A significant group-level increase in T was observed, though this was smaller than anticipated (~ 10%, d = 0.27) with substantial intragroup variation. No group-level change in C or mating preferences emerged. Testosterone change did not significantly predict a change in short- or long-term mating preference from baseline, even with inclusion of C change as a moderator. The current findings suggest that modest exercise-induced increases in T concentration have little impact on male mating strategies. Pharmaceutical interventions, which produce larger and more consistent T increases, may be required to observe mating strategy change.

No relationship between the digit ratios (2D:4D) and salivary testosterone change: Study on men under an acute exercise

The digit ratio (2D:4D) is said to be a potential marker of exposure to prenatal sex steroids. Some studies suggest that the 2D:4D is also linked with the testosterone response to challenging situations due to organizational effect of prenatal hormonal milieu on adult endocrine functioning. However, up to date, there were only four studies (conducted on small samples) that examined the 2D:4D and the testosterone response to a challenging situation (i.e. physical exertion or aggressive context). Here, we examined the relationship between the 2D:4D and the testosterone change under an acute exercise among 97 men. We found that the digit ratios (the right 2D:4D, the left 2D:4D, and the right minus left 2D:4D) were neither predictors of pre-exercise testosterone, nor the change in testosterone level after a cycling task. Our results add a contradictory to previous studies evidence in a discussion on the links of the 2D:4D and the testosterone change.

Testosterone supplementation and body composition: results from a meta-analysis of observational studies

PURPOSE

The concept of testosterone (T) supplementation (TS) as a new anti-obesity medication in men with testosterone deficiency syndrome (TDS) is emerging. Data from placebo-controlled trials are more conflicting. The aim of this study is to systematically review and meta-analyze available observational and register studies reporting data on body composition in studies on TS in TDS.

METHODS

An extensive MEDLINE, Embase, and Cochrane search was performed including the following words: "testosterone" and "body composition." All observational studies comparing the effect of TS on body weight and other body composition and metabolic endpoints were considered.

RESULTS

Out of 824 retrieved articles, 32 were included in the study enrolling 4513 patients (mean age 51.7 ± 6.1 years). TS was associated with a time-dependent reduction in body weight and waist circumference (WC). The estimated weight loss and WC reduction at 24 months were -3.50 [-5.21; -1.80] kg and -6.23 [-7.94; -4.76] cm, respectively. TS was also associated with a significant reduction in fat and with an increase in lean mass as well as with a reduction in fasting glycemia and insulin resistance. In addition, an improvement of lipid profile (reduction in total cholesterol as well as of triglyceride levels and an improvement in HDL cholesterol levels) and in both systolic and diastolic blood pressure was observed.

CONCLUSIONS

Present data support the view of a positive effect of TS on body composition and on glucose and lipid metabolism. In addition, a significant effect on body weight loss was observed, which should be confirmed by a specifically designed RCT.

Is salivary cortisol moderating the relationship between salivary testosterone and hand-grip strength in healthy men?

This study examined the moderating effect of cortisol (C) on the relationship between testosterone (T) and hand-grip strength (HGS) in healthy young men. Sixty-five males were monitored for salivary T, C and HGS before and 15 min after a short bout (5 × 6-s trials) of sprint cycling exercise. Sprint exercise promoted (p < .05) positive changes in T (6.1 ± 24.9%) and HGS (3.4 ± 7.5%), but a negative C response (-14.4 ± 33.1%). The T and C measures did not independently predict HGS, but a significant T × C interaction was found in relation to these outcomes. Further testing revealed that pre-test T and HGS were negatively associated (p < .05), but only in men with high C levels. The exercise changes in T and HGS were also negatively related in men with low C levels (p < .05), but no relationship was seen in men with high C levels. In summary, complex relationships between T and HGS emerged when considering C as a moderating variable. The pre-test combination of high C and low T levels favoured absolute HGS, whereas low pre-test C levels and a smaller T change were linked to larger HGS changes. These associations suggest that, in the current format, T is not necessarily anabolic to muscle strength in healthy young men. Such complexities could also explain some of the inconsistent T relationships with physical performance in lesser trained male populations.

Digit ratio (2D:4D) and salivary testosterone, oestradiol and cortisol levels under challenge: Evidence for prenatal effects on adult endocrine responses

BACKGROUND

Digit ratio (2D:4D) is a marker for prenatal sex steroids and a correlate of sporting performance. This association may exist because low 2D:4D is linked to high prenatal levels of testosterone (T) and low oestrogens (E). It was recently suggested that low 2D:4D, and particularly low right-left 2D:4D (or Dr-l), is a marker for T changes in response to physical and aggressive challenges. If correct, this link may in part explain the association between 2D:4D and sports performance.

AIMS

We tested this hypothesis in adults.

STUDY DESIGN

Three experimental treatments were completed using a randomised, cross-over design; (i) cycle sprints plus an aggressive video (S+V), (ii) aggressive video plus cycle sprints (V+S), and (iii) a control session.

SUBJECTS

24 healthy adults (12 men and 12 women).

OUTCOME MEASURES

Salivary T, oestradiol (E2) and cortisol (C) levels were measured on six occasions across each session and pooled for analysis.

RESULTS

The S+V treatment was associated with a rise in T and C levels, and Dr-l was significantly and negatively correlated with T and E2 with these effects confined to men. The right 2D:4D and Dr-l were also negatively correlated with the T/C ratio and Dr-l negatively related to the E2/C ratio in men during the S+V treatment.

CONCLUSIONS

We suggest that the hormonal responses to a challenge are programmed by prenatal levels of T and E with possible links to sporting performance in adulthood.