the odors, of adolescent boys. It fuels healthy libido, muscle mass,
and energy levels. Getting the right amount in your system is
important. When testosterone levels are too low, it can lead to
fatigue, depression, and low sex drive.^16 These kinds of symptoms
in men may partially explain the proliferation of Low
T commercials on television and supplements that promise to
boost testosterone levels.
Researchers have discovered a correlation between testos-
terone and sensation-seeking behavior. An April 1999 study in the
Journal of Behavioral Medicineexamined the medical records of over
4,000 men. Those with higher levels of testosterone were 24 percent
more likely to report multiple injuries, 35 percent more likely to
report having a sexually transmitted disease, and a stunning
151 percent more likely to smoke. These risk factors are clearly
related to high sensation-seeking activities. And the higher the
levels of testosterone, the more likely the research subjects were
to engage in sensation-seeking behaviors.^17
Some researchers connect the relatively higher levels of
testosterone in men with their higher thrill- and adventure-
seeking scores. What’s more, several studies show a significant
relationship between testosterone and aggression but interestingly
only in people with low levels of cortisol (like high sensation-
seekers).^18
Higher levels of testosterone are associated with higher
levels of sensation-seeking in both men and women.^19
Additionally, testosterone levels don’t remain stable over time.
They naturally decrease as we get older, and so do sensation-
seeking scores. This might explain why many TV shows, movies,
and amateur videos feature younger people doing thrill- and adven-
ture-seeking stunts. Another chemical in your body that influences
sensation-seeking is monoamine oxidase or MAO. MAO is an
enzyme important in determining the levels of neurotransmitters
that cross the tiny spaces between our brain cells called synapses.
MAO is like a biochemical Pac Man, gobbling up stray neurotrans-
mitters, the chemical messengers that help our neurons commu-
nicate. By gobbling up the errant neurotransmitters, MAO regulates
their presence in our system. High levels of neurotransmitters
increase neural activity, and low levels decrease it. High levels of
MAO mean fewer neurotransmitters, which leads to low sensitivity.
Conversely, low levels of MAO mean more neurotransmitters,
which leads to high sensitivity.39 / Born to Be WildDownloaded from https://www.cambridge.org/core. Access paid by the UCSF Library, on 11 Nov 2019 at 14:20:40, subject to the Cambridge