Encyclopedia of Health and Medicine

W–Z
weight and pain The influence of excessive body
weight on the experience of PAIN. Excessive body
weight may itself be the cause of pain, particularly
pain that affects the joints, or may contribute to
pain due to underlying health conditions such as
FIBROMYALGIA, ANKYLOSING SPONDYLITIS, PLANTAR
FASCIITIS, and GOUT. OBESITY
is a risk factor for
numerous chronic conditions that cause pain
including OSTEOARTHRITIS and chronic BACK PAIN.
Excessive Body Weight
and Musculoskeletal Structures
Excessive body weight has numerous adverse
effects on the musculoskeletal system because it
alters the person’s posture and movement. The
effects are most noticeable on the joints, which
may develop chronic discomfort and aching. Every
10 pounds of body weight in excess of healthy
weight increases the force the knees experience
during walking by about 50 pounds each time the
foot strikes the ground. Weight-bearing joints
below the waist (hips, knees, ankles, and feet) are
particularly vulnerable to weight-related pain.
Because excessive body weight strains musculoskeletal
structures, it often contributes to pain
symptoms related to chronic conditions such as
back pain. The pressure of the excessive weight
over time may also cause damage to the joints;
numerous studies implicate overweight and obesity
in the development or escalated progression of
osteoarthritis, the most common degenerative disorder
affecting the joints.
Physical Activity and Pain Relief
Regular, moderate physical activity often improves
chronic pain regardless of its source. Exercise, particularly
activities that extend 20 minutes or
longer, causes the body to release endorphins and
389
other substances that act like natural pain relievers
in the brain. The effects of these substances
lasts far longer than the exercise session.
Regular physical exercise also strengthens muscles
and connective tissues and broadens flexibility.
These effects increase the stability of the joints,
improving joint function. Even when pain is unrelated
to the joints, these effects are beneficial for
most underlying health conditions for which pain
is a key symptom. And regular physical activity
improves cardiovascular function, notably circulation,
increasing the flow of blood to all parts of the
body. Increased blood flow brings oxygen and
other vital substances to areas of HEALING, helping
both to speed healing and to keep scar tissue from
stiffening.
However, the natural tendency is to avoid
activity when pain is present. A reduced level of
activity may be appropriate for certain health conditions,
especially for a defined period of recovery
time. Extended inactivity contributes to, rather
than relieves, pain. It may also give rise to other
health complications such as DEEP VEIN THROMBOSIS
(DVT) or PULMONARY EMBOLISM (blood clots in the
veins of the legs or in the lungs), pneumonia
(fluid accumulation in the lungs, and pressure
sores or decubitus ulcers. Extended inactivity also
tends to encourage further weight gain, even
when food intake remains the same, because
reduced movement means the body uses less
energy.
Appropriate Physical Activity
The doctor can recommend activities and intensity
levels that are appropriate for both the health condition
and the person’s FITNESS LEVEL. A physical
therapist or qualified fitness and training expert
can develop a customized program for progressive