Development across the Life Span 343the lens of the eye hardens, becoming unable to change its shape to shift focus. Hearing
loss may begin in the 40s and 50s but often does not become noticeable until the 60s or
70s, when hearing aids may become necessary.
In the 40s, while most adults are able to experience some security and stability
without the worries and concerns of adolescence and young adulthood, physical aging
continues: Skin begins to show more wrinkles, hair turns gray (or falls out), vision and
hearing decline further, and physical strength may begin to decline (Frontera et al., 1991).
In the 50s, these changes continue. Throughout middle age, weight may increase as the
rate at which the body functions slows down but eating increases and less time is spent
exercising. Height begins to decrease, with about half an inch of height lost for every
10 years past age 40, although people with the bone-loss disease osteoporosis may lose
up to 8 inches or more (Cummings & Melton, 2002). Although sexual functioning usually
does not decline in middle age, opportunities for sexual activity may be fewer than in
the days of young adulthood (Hodson & Skeen, 1994; Kalra et al., 2011; Williams, 1995).
Children, mortgages, and career worries can put a damper on middle-age romance.
MENOPAUSE In a woman’s 40s, the levels of the female hormone estrogen decline as
the body’s reproductive system prepares to cease that function. Some women begin to
experience “hot flashes,” a sudden sensation of heat and sweating that may keep them
awake at night. Interestingly, in some cultures, particularly those in which the diet
contains high amounts of soy products, hot flashes are almost nonexistent (Cassidy et
al., 1994; Lock, 1994). However, one study suggests soy intake is not a primary factor
(Gold et al., 2013). The changes that happen at this time are called the climacteric, and
the period of 5 to 10 years over which these changes occur is called perimenopause. At
an average age of 51, most women will cease ovulation altogether, ending their repro-
ductive years. The cessation of ovulation and the menstrual cycle is called menopause
(Mishell, 2001). Many women look forward to the freedom from monthly menstruation
and fear of unplanned pregnancies (Adler et al., 2000; Hvas, 2001; Leon et al., 2007).
Do men go through anything like menopause?Men also go through a time of sexual changes, but it is much more gradual and less
dramatic than menopause. In males, andropause (Carruthers, 2001; Renneboog, 2012)
usually begins in the 40s with a decline in several hormones, primarily testosterone (the
major male hormone). Physical symptoms are also less dramatic but no less troubling:
fatigue, irritability, possible problems in sexual functioning, and reduced sperm count.
Males, however, rarely lose all reproductive ability.
EFFECTS OF AGING ON HEALTH It is in middle age that many health problems first
occur, although their true cause may have begun in the young adulthood years. Young
adults may smoke, drink heavily, stay up late, and get dark tans, and the wear and tear
that this lifestyle causes on their bodies will not become obvious until their 40s and 50s.
Some of the common health problems that may show up in middle age are high blood
pressure, skin cancer, heart problems, arthritis, and obesity. High blood pressure can be
caused by lifestyle factors such as obesity and stress but may also be related to hereditary
factors (Rudd & Osterberg, 2002). Sleep problems, such as loud snoring and sleep apnea (in
which breathing stops for 10 seconds or more), may also take their toll on physical health.
There is some evidence that high blood pressure and apnea are linked, although the link
very well may be the common factor of obesity (Nieto et al., 2000). Statistically, the four most
frequent health-related causes of death in middle age (45 to 64 years of age) are cancer, fol-
lowed closely by heart disease, chronic respiratory disease, and stroke for men (Centers for
Disease Control [CDC], 2013a). For women in that age group, the results are slightly differ-
ent: cancer, followed by heart disease as a much more distant second, chronic lung disease,
and chronic liver disease (CDC, 2013b). Strokes were the fifth leading cause for women.
Many people end up needing bifocals
at some point in their 30s or 40s, as
the lens hardens and loses its ability
to visually accommodate to different
distances of objects.menopause
the cessation of ovulation and men-
strual cycles and the end of a womanos
reRroductive caRaDility.andropause
gradual changes in the seZual hor-
mones and reRroductive system of
middle-aged males.