The Perils of Pedaling
If you get all your exercise from biking, beware: It may lead to
brittle bones in old age
By MARILYN CHASE
Staff Reporter of THE WALL STREET JOURNAL
October 10, 2005; Page R7
Bicycling, spurred by icons like Tour de France winner Lance
Armstrong, is a hugely popular adult sport, drawing 85.7 million
Americans over age 16 to ride for fun and fitness. But cyclists who
get all their exercise on two wheels may face a hidden health hazard:
fragile bones.
Once seen mainly as a risk to women, weak bones afflict men, too --
even elite athletes. What people do in their 20s, 30s and 40s can
shore up a strong skeleton or start a silent erosion, leading to
brittle bones that can shatter in old age.
THE JOURNAL REPORT

"Osteoporosis is still thought of as a disease of little old ladies.
It's a misconception," says Jeanne Nichols, professor of exercise and
nutrition science at San Diego State University. She studies the
health of athletes and has found that men are also vulnerable to
imbalances in exercise and nutrition that can undermine skeletal
health.
In her research, Dr. Nichols found that male master cyclists --
ultrafit senior athletes who rode for an average of 20 years --
suffer
surprisingly high rates of a precursor to osteoporosis, the thin and
porous bones that are prone to fractures. While more research is
needed, she says that training exclusively on the bike, excluding
weight-bearing exercise, undermines bone strength.
Beneficial Pressure
Healthy bone cells undergo constant turnover in a process of
breakdown
and replacement. Building new bone requires the pressure of body
weight and impact on the skeleton to add new cells. Running and
jumping provide such stimuli. But as joints get injured, people turn
to low-impact sports. While this avoids pain, it also deprives bones
of a growth trigger.
Bicycling is a non-weight-bearing exercise that spares the joints but
softens the impact that sparks growth. In addition, cyclists sweat a
lot, losing calcium in the process. Some elite cyclists also strive
to
be very lean for speed. Thin builds are a risk factor for
osteoporosis, along with female sex, and Caucasian or Asian
ethnicity.
Smoking, alcohol and drugs such as the anti-inflammatory prednisone
can add to risks.
Sound nutrition, with adequate calcium and vitamin D, is essential.
But many adults are calcium-deficient because they don't like milk,
want to avoid calories, or are lactose-intolerant. Cyclists who ride
extreme events like centuries, or 100-mile races, can depress the
hormones testosterone and estrogen, further weakening bones. Men on
antihormonal treatment for prostate cancer also are at risk.
Slow Decline
People build strong bones from childhood, reaching maximum bone
density by their mid-20s. After that, says San Francisco orthopedic
surgeon Christopher Cox, "it's a slow degradation. Women lose bone
rapidly around menopause, but even men lose bone. If you have only so
much, and if you do a high-risk sport, you may find that out in your
60s when you can't do much about it." The wake-up call may be a
broken
hip, or a stress fracture of the vertebrae.
ROLLING TOWARD TROUBLE?

Factors That Undermine Bones
--Getting only low-impact exercise
--Overly thin build
--Calcium-poor diet
--Female gender
--Caucasian or Asian ethnicity
--Tobacco or alcohol use
--Medications (including prednisone)
--Low levels of sex hormones
Building Bone Strength
--Good overall nutrition (with plenty of calcium and vitamin D)
--Maintain sensible weight
--Alternate cycling with sports that involve running or jumping
--Weight training
--If osteoporosis is present, consider medicines like Fosamax
Even to the well-informed fitness buff, Dr. Nichols's research came
as
a surprise. An avid cyclist, Dr. Cox says he was "totally caught off
guard" by Dr. Nichols's 2003 study in the journal Osteoporosis
International. Formerly casual about diet, he now takes calcium and
vitamin D as nutritional insurance. He also tells his patients who
cycle that it's a good idea to take supplements if they don't eat
dairy foods, and to balance cycling with weight training.
Dr. Nichols's research studied 27 master cyclists with an average age
of 51 who had cycled competitively for 20 years as their main form of
exercise. Measuring their bone-mineral density, she compared it with
that of two other groups: age-matched recreational gym goers, and
young, elite cyclists at the same competitive level as the master
cyclists.
She used a Dexa scan, or dual energy X-ray absorptiometry, a
very-low-radiation X-ray that measures bone density. The master
cyclists' bone density was lower than that of both the younger
cyclists and their age peers who didn't cycle. More than two-thirds
were low enough to be classed as having either osteoporosis or the
precursor condition, osteopenia. Four men, or 15% of the master
cyclists, had outright osteoporosis. For some, it took a while to
absorb the diagnosis.
"The psychology was interesting," she says. Some men went into
denial.
" 'I'm a male. I can't be osteoporotic,' " she recalls some saying.
Not long after the study, one volunteer had a freak accident in a
parking lot, falling off his bike and fracturing his hip. He began
lifting weights and taking the bone-building drug Fosamax, and
started
his whole family on calcium.
A former runner turned cyclist, the 57-year-old Dr. Nichols says she
got the message herself. "I saw my own [bone density] take a drop
when
I converted from running to cycling," she says. "I said, all right,
practice what you preach." She says she now balances her bike time
with weight training and exercise classes that keep her on her feet
twice a week to keep her skeleton strong. She recommends that
athletes
get regular bone scans, eat a balanced diet rich in calcium and
vitamin D, and supplement cycling with resistance or impact exercise
as she does. If bone scans show eroding density that points to a risk
of fractures, Dr. Nichols urges people to discuss drug treatments
such
as Fosamax.
Spotty Coverage
Men curious about their bone density should be aware that insurance
coverage for Dexa screening is spotty, so they may end up paying out
of pocket. The cost ranges from $150 to $350, depending on location.
Plans may cover men over 50 who have a history of broken bones or
other obvious risk factors.
Dr. Nichols's findings are preliminary and should be interpreted with
caution, some experts say. "It's interesting, but it's a hypothesis,"
says Eric Orwoll, professor of medicine at Oregon Health Sciences
University, and an authority on male osteoporosis. While he agrees
that men face "a strikingly high chance of fractures in later years,"
he says that bikers' bones may simply be different from those of
noncyclists and adds that more research is needed. Others point out
that Dexa scans were originally calibrated for women, so much less is
known about normal and abnormal density scores for men.
Others think the evidence is compelling enough to shape their
regimen.
Jim Cushing-Murray of Frisco, Colo., one of the master cyclists in
Dr.
Nichols's study group who fared well, credits years of cross-training
for helping him avoid osteoporosis. A bike racer since 1966 and
former
national road champion, Mr. Cushing Murray, now 64, does heavy weight
lifting every winter to balance the summer cycling season. That same
regimen also works for his wife, Joann Meyer, 62, the U.S. Cycling
Federation 2005 women's road champion, who adds: "It has paid off."
Orthopedic surgeon Eric Heiden, an Olympic gold medalist in speed
skating in 1980 who later took up pro cycling, follows a regimen that
includes lots of milk and twice-weekly sessions that alternate the
bike with weights. His medical rounds at the University of California
at Davis also keep him on his feet.
"I'm 47," says Dr. Heiden, "so a guy like me better keep walking."