Ultradian rhythmicity and induced changes in salivary testosterone

Abstract

Testosterone and cortisol respond to exercise stimuli and modulate adaptation. Episodic basal secretion of these hormones may modify the responsiveness of these hormones. We sought to identify episodic steroid secretion via frequent salivary sampling and investigate any interaction between ultradian rhythmicity and induced changes in testosterone. Salivary testosterone and cortisol concentrations of seven males (age 20-40 years) were measured every 10 min between 0800 and 1600 h on three consecutive days. On either the second or third day, three interventions designed to elicit a hormonal response were randomly assigned: sprint exercise (two 30-s maximal efforts on a cycle ergometer); boxing (two 30-s maximal punching efforts); and a violent video game (10 min of player vs. player combat). On the other days subjects were inactive. Testosterone data on non-intervention days suggested pulsatile secretion with a pulse interval of 47 +/- 9 min (mean +/- SD). The sprint intervention substantially affected hormones: it elicited a small transient elevation in testosterone (by a factor of 1.21; factor 90% confidence limits x/ divided by 1.21) 10 min after exercise, and a moderate elevation in cortisol peaking 50 min post-exercise (factor 2.3; x/ divided by 2.6). The testosterone response correlated with the change in testosterone concentration in the 10 min prior to the sprint (r = 0.78; 90% CL 0.22-0.95) and with a measure of randomness in testosterone fluctuations (r = 0.83; 0.35-0.96). Thus, the salivary testosterone response to exercise may be dependent on the underlying ultradian rhythm and aspects of its regulation. This interaction may have important implications for adaptation to exercise.

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

“…The ratio measures of T/C, T/E2 and E2/C were also calculated. To control for circadian variation [25], testing was conducted between 1100 and 1600 h. Within this time period, each participant reported to the testing facility at the same time of day (± 1 h) to complete their own individual assessments. The subjects were asked to avoid any strenuous exercise in the 24-48 h before testing to eliminate any fatigue effect.…”

Salivary testosterone responses to a physical and psychological stimulus and subsequent effects on physical performance in healthy adults

“…The exercise-induced changes in T are likely to be regulated by several factors such as cycling cadence, 36 heart rate, 37 and perceived exertion. 37 Whilst sprint cycling exercise can reliably increase T concentrations in untrained, active 10,18,38 or highly-trained men, 10,11,36 women do not always exhibit a T response. 21,27 This disparity could be explained by differences in the cycling protocols employed (e.g.…”

“…The chosen format was based on prior work to ensure a T rise. 5,12,18 Toe clips were used to prevent slippage from the pedals and strong verbal encouragement was given to ensure maximal effort was applied during each trial.…”

“…1 ml over 1-2 minutes) without stimulation before each stimulus and 15 minutes afterwards to coincide with expected T changes in this fluid. 13,16,18 The samples were stored according to published guidelines. 32 The time between sample collections was ~30 minutes, once allowing for the physical tests, treatments and subsequent recovery periods.…”

“…In healthy men (non-athletes), exposure to the same type of video also produced a marginal T increase of 8-12%, 10,17 as did an aggressive video game. 18 To our knowledge, no studies have examined whether an aggressive video can improve T availability and physical performance in healthy adults, nor how this treatment compares to a physical stimulus.…”