Testosterone and the Brain
Testosterone plays a critical role in the brain. Research has shown that testosterone receptors are found throughout the brain, including in regions involved in motivation, reward, and decision-making (Bhasin et al., 2010). It has been linked to a range of behaviours, including competition and challenging, risk-taking, and sexual behaviour, due to its impact on liido.
One way in which testosterone impacts the brain is by influencing the release of dopamine. Dopamine is a neurotransmitter involved in the reward and motivation pathways. Research has shown that testosterone can increase the release of dopamine in response to a reward (Wood et al., 2014). This effect is particularly pronounced in males, who tend to have higher levels of testosterone and a stronger dopamine response to rewards than females.
Effort-based rewards are rewards that are earned through hard work and effort, such as completing a difficult task or achieving a challenging goal. Research has suggested that testosterone may play a critical role in making effort-based rewards more appealing and motivating.
One study examined the effects of testosterone on effort-based decision-making in male rats (Salamone et al., 2015). The researchers found that rats given testosterone were more likely to choose a high-effort, high-reward option than rats given a placebo. The testosterone-treated rats were willing to work harder to obtain the reward, indicating testosterone increased their motivation to engage in physical tasks.
Similar results have been found in humans.
A study of male athletes found that those with higher levels of testosterone were more likely to engage in high-intensity training and were more motivated to achieve their goals (Hirschberg et al., 2018). Another study found that men given testosterone were more willing to put in effort to earn a monetary reward (Zilioli et al., 2015).
Research has shown that testosterone stimulates the growth of muscle fibers and increases the synthesis of muscle proteins (Bhasin et al., 2010). This effect is particularly pronounced in men, who have higher levels of testosterone than women and tend to have greater muscle mass and strength as a result.Recent research has suggested that testosterone may also impact physical performance through its effects on the brain.
However, testosterone may also impact physical performance through its effects on motivation and effort. Research has shown that testosterone can increase the willingness to engage in physical activity and the motivation to achieve physical goals (Hirschberg et al., 2018). This effect is particularly pronounced in individuals who are already highly motivated to engage in physical activity, such as athletes.
Testosterone and Competition
Testosterone has also been linked to competitive behaviour, particularly in males. There is now evidence showing that testosterone levels increase in response to competition, and that winning a competition can lead to a further increase in testosterone (Mehta and Josephs, 2010). This effect has been observed in men and women but ids more pronounced in men.
The Relationship Between Testosterone and Cortisol
Cortisol is a hormone that is released in response to stress. High levels of cortisol can have negative effects on physical and mental health, including impairing cognitive function and suppressing the immune system. Research has suggested that testosterone may play a role in regulating the release of cortisol and mitigating its negative effects.
A study looking at the effects of testosterone on cortisol responses to stress in male athletes (Oliver et al., 2009) found that athletes given testosterone had a blunted cortisol response to a physical stressor, indicating that testosterone may help regulate the body's stress response. Also the testosterone-treated athletes reported feeling less anxious and more confident during the stressor, suggesting that testosterone may have psychological effects on stress responses.
Testosterone plays an important role in regulating a range of hormones and subsequent behaviours, including motivation, physical performance, and competitive behaviour. It impacts the brain by influencing the release of dopamine and may make effort-based rewards more appealing and motivating. Testosterone can also impact physical performance by increasing muscle mass and strength, as well as the motivation to engage in physical activity. Further research is needed to fully understand the effects of testosterone on the brain and behaviour. This could explain why some men with testosterone deficiency feel lacking in confidence, anxious, stresster and low motivation to train.
References:
Archer, J. (2006). Testosterone and human aggression: an evaluation of the challenge hypothesis. Neuroscience & Biobehavioral Reviews, 30(3), 319-345.
Bhasin, S., Woodhouse, L., Casaburi, R., Singh, A. B., Mac, R. P., Lee, M., ... & Dzekov, C. (2010). Testosterone dose-response relationships in healthy young men. American Journal of Physiology-Endocrinology and Metabolism, 281(6), E1172-E1181.
Hirschberg, A. L., Zahavi, D., Simonsen, M., & Höök, M. (2018). Testosterone is associated with self-employment among male graduates. Journal of Economic Psychology, 67, 33-43.
Mehta, P. H., & Josephs, R. A. (2010). Testosterone and cortisol jointly regulate dominance: Evidence