Humans start getting shorter as they age. The process begins in the 30s and the change can become perceptible in the 40s. According to research from the University of Arkansas for Medical Science, men lose about an inch between 30 and 70, while women might lose 2 inches or more.
Interestingly, shrinking also refers to the brain getting smaller too. The prefrontal cortex and hippocampus, two parts important to learning and memory, start to shrivel and die at a rate of around 50,000 neurons a day after the age 30. Of course, this doesn’t even put a dent in the 100 billion neurons that make up your brain—and if you stay active, you can keep growing new ones, thanks to neuroplasticity.
Now, men, don’t be alarmed. As you get older, you might also experience shrinking of the penis and testicles. Farther more, as your skin loses elasticity, your scrotal sac will hang more loosely. This can cause an appearance of reduced size. Of course, while this has some impact on your sex drive, it does not impair you from maintaining healthy sexual relationships.