Is it true that people can have a midlife crisis, or is it a myth?
—Paul Graham, Pleasantville, N.Y.

David Almeida, professor of human development and family studies at Pennsylvania State University, responds:

MANY PEOPLE EXPECT that midlife brings forth inevitable crisis, but that idea is not supported by social science. In fact, only 26 percent of adults older than 40 reported having a crisis, according to a recent study. That is not to say that the middle-aged do not experience challenges and psychological distress, but these feelings tend to be brought on by stressful events, such as health problems or losing a parent—not by age alone.

The notion of the midlife crisis began with followers of Sigmund Freud, who thought that during middle age everyone’s thoughts were driven by the fear of impending death. Although plenty of aging people try to cling to their youth, my research shows that the middle-aged are actually happier and more satisfied with their daily life than younger adults are. They have found their way in the world, they are settled into their job, and their kids are older. On average, midlife is a happy time.

Midlife crises are often defined by someone else’s perception rather than our own. A lot of the stereotypical hallmarks, such as the sudden purchase of an expensive sports car, probably have more to do with improved financial status than with a search for youth. People can finally afford some finer, more expensive pleasures.

We also do not see many genuine midlife crises because middle-aged adults simply do not have time for a crisis. In this period they are often responsible for their children and their aging parents. They also move into management positions and have additional responsibilities at work.

The concept of the midlife crisis sometimes serves as a convenient excuse for behaviors that just happen to take place in one’s 40s or 50s. Dissatisfaction in your job? Relationship problems? There are a multitude of explanations for these experiences—and although it may seem easy to blame a midlife crisis, age most likely has nothing to do with it.

Why does listening to music make it so much easier for me to complete a challenging workout?
—Rachel Birkey, San Francisco

Mark A. W. Andrews, professor of physiology and director of the Independent Study Pathway at the Lake Erie College of Osteopathic Medicine, replies:

MOST OF US have experienced the boost music brings to a workout—increased motivation, distraction from fatigue and the perception that time is passing more quickly. Indeed, working out with music has been proved to increase physical performance and levels of alertness, and it may aid the release of brain chemicals that influence mood.

Recent research confirms that listening to music is especially advantageous in boosting physical performance among those needing to exercise to help with obesity or heart problems. Music has been found to increase physical performance by more than 20 percent in many such individuals because they perceive their workout to be easier.

Prehistoric evidence suggests that making and listening to music is one of the basic actions of humans. Even infants react to upbeat music by moving their arms and legs rhythmically. Like music, aerobic exercise and basic physiological functions such as heartbeat and respiration involve rhythmic activity. Because the body is used to rhythms, the influence of a beat helps us to readily organize our physical movements.

In the case of aerobic exercise, a straightforward, high-paced rhythm seems to be an important aspect. Research indicates that genres such as heavy metal, fast pop and hip-hop are best able to excite the nervous system and aid physical behavior and self-expression. Although evidence is incomplete, such music may also help generate the fast-paced beta waves in the brain, which are characteristic of a strongly engaged, aroused and, most important, motivated mind. In addition, music and rhythmic motion may encourage the brain to release opioids, chemicals related to pleasure and euphoria.

On the other hand, although hard rock has an appropriate speed of rhythm, some hard rock appears to destroy the symmetry between the cerebral hemispheres and induce alarm, causing performance to decrease, possibly because of irregular beats and shrill frequencies. And weight training differs from rhythmic aerobic exercise in that it is not so dependent on a fast pace—performance seems to benefit from medium tempo music coupled with inspirational lyrics.

Note: This article was originally printed with the title, "Ask the Brains".