Much of your body is already fully developed even before you reach adulthood. According to Medline Plus, men's genitals are fully developed by 16 to 17 years old. Although you might reach maturity in many areas before adulthood, there are still changes and declines that take place, especially between 35 to 60 years old during middle adulthood.
You will reach your full height by the time you are in your mid-20s. As you progress through adulthood, you might notice that your skin becomes thinner and loses elasticity; wounds take longer to heal, and you start to get wrinkles. To protect your skin and its appearance, wear sunscreen that is at least 30 SPF, even in winter. Your hair might start to turn gray. You are most likely to get gray hair around the same time that your parents did.
As you age, substances such as alcohol will stay in your system longer. You are also at an increased risk for heart disease and high blood pressure. To stay healthy, the World Health Organization recommends doing 30 minutes of moderate activity at least five days a week. This helps prevent heart disease, osteoarthritis and hypertension as well as improving balance and coordination.
Hearing and Vision
Your vision and hearing might start to decline during middle adulthood. According to Minnesota State University, you might experience a small decline in hearing during early to middle adulthood. Hearing decline is most noticeable in your mid-40s. You also might have less focus and lose near vision, causing you to need more light for tasks such as reading.
Somewhere in middle adulthood, women will experience menopause. In menopause, hormonal changes cause a stop in menstruation and ovulation, completely reducing fertility and making it impossible to bear children. Men have reduced fertility because of a lower sperm count and a decline in testosterone levels, but they still can produce children until the mid-70s.
Minnesota State University says you might experience a decline in physical performance around 30. Inactivity can cause you to lose muscle mass and flexibility. You can increase your physical performance and muscle mass by exercising regularly, especially with weight-bearing exercises such as lifting.