Author: Richard Weil, MEd, CDE
Medical Editor: Melissa Conrad Stöppler, MD
Bike riding is terrific aerobic exercise, a healthy and economical way to commute, and a great way to run errands, sightsee, and get around town. There is, however, a potential downside to biking; sitting on the bicycle seat may result in the compression of nerves and blood vessels of the vulnerable area of the body called the perineum. The perineum is the area between the anus and the base of the penis in males and between the anus and the vagina in females; it contains both blood vessels and nerves. Compression of the perineum can lead to nerve damage, swelling, artery insufficiency (lack of blood flow through the vessel), and even occlusion (blockage) of blood vessels, which in turn can lead to temporary or permanent groin numbness, tingling sensations, decreased penile blood supply, erectile dysfunction (impotence), decreased orgasm sensitivity, and pain. These cycling-related perineal symptoms are the subject of this article.
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How common are cycling-related perineal symptoms?
- In a study of perineal
compression and blood flow to the penis in male cyclists, penile blood supply
decreased significantly in 70% of the 40 cyclists who participated in the study.
Numbness in the genital area was reported by 61% of the cyclists, and 19% of the
cyclists who rode their bikes more than 250 miles per week complained of
- In a study of 463 cyclists competing in a long-distance
cycling event (200 miles), perineal numbness during the ride was experienced by
31% of the cyclists and was associated with erectile dysfunction that lasted as
long as one week after the event.
- In a study called a meta-analysis (where
many studies on the same subject are summarized), results of 35 studies
conducted between 1981 and 2004 that examined the relationship between cycling
and erectile dysfunction showed that the prevalence of moderate to severe
erectile dysfunction in bicyclists was 4.2%, and that riding more than three hours
per week was a risk factor for developing this condition.
- In another
meta-analysis investigating perineal symptoms and cycling (62 articles),
numbness of the genitalia was reported in 50%-91% of all cyclists, and erectile
dysfunction was reported in 13%-24% of all cyclists.
Perineal symptoms are not experienced by all cyclists, but this is certainly
something to be aware of, particularly if you plan to ride long distances.
What are factors that cause perineal symptoms?
The interaction between the
bicycle seat (saddle) and the perineum is the culprit in all cases of perineal
symptoms in cyclists. The interaction is dependent on the vertical (downward)
and shear (backward) force of the perineum on the saddle, the weight of the
rider, the height and angle between the saddle and the handlebars, the saddle
tilt angle, and the shape of the saddle. Below is a review of these factors.
Vertical loads of the perineum to the saddle can be as high as
52% of the rider's body weight, whereas shear loads can reach 12% of body weight. The vertical pressure is dependent on the rider's body weight as well as
riding position. Although there is no conclusive data as to what degree of load
increases the likelihood of symptoms, there does appear to be a relationship
between load stress and compression of the perineum.
Saddle and handlebar height
In a study of erectile dysfunction and bicycle
characteristics, researchers determined that keeping handlebar height lower
than saddle height in long-distance cyclists was associated with less erectile
dysfunction, perhaps because this configuration puts the rider in a
leaning-forward position which may reduce vertical load on the perineum. This
position may or may not apply to recreational riders on touring or hybrid bikes
where speed and aerodynamics are not as important, but there is no research to
support the claim one way or the other.
In three studies of the angle of the saddle, it was confirmed
that a downward tilted saddle reduced stress and compression on the perineum.
This is probably because the backward stress puts the weight of the rider on the ischial tuberosities (the "sit bones" in your buttocks) and off of the perineal
Bicycle saddle design has been the target of a great deal of scholarly and
commercial research. A number of years ago, bicycle saddles started to be
manufactured with cutouts down the middle with the hope that this would relieve
pressure on the perineum and reduce compression symptoms. Indeed, in one study,
55% of the subjects ranked the partial cutout saddle as the most comfortable.
In a recent study of a new saddle (Selle SMP) with a large cutout and downward
facing nose (the front of the saddle), the saddle was clearly superior in
preventing vascular compression and penile blood flow occlusion compared with
more standard saddle designs.
Interestingly, in a study on saddle shape and
penile blood flow, a narrow saddle was associated with greater reductions in
penile blood flow than a wider saddle, leading the researchers to conclude that
the narrow saddle could be a source of blunt perineal trauma. In a study
involving computer analysis of forces on the perineum with wide and narrow
saddle design, it was also shown that a wide saddle capable of supporting the
sit bones was superior for reducing perineal stress compared with a narrow
saddle. Most racing saddles, however, are narrow, and this may have some effect
on perineal symptoms for some riders. In a study of a saddle without a nose
compared to a traditional saddle with a protruding nose, the traditional saddle
was associated with two times greater perineal pressure than the noseless
saddle. These results have been confirmed by another study. However, it has
been reported by riders that noseless saddles lead to a feeling of less control
over the bike since their thighs are not fully in contact with the saddle. More
research needs to be done on optimal width and shape of the saddle.
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Should I buy a gel seat cover?
There's no evidence that a gel seat will help
reduce perineal symptoms. In fact, in some cases, too soft a seat can cause more
discomfort than a slightly firmer saddle (sort of like how too soft a mattress
can lead to back pain). A gel seat may work better for short-distance riding
like errands or commuting, but it might not work as well for longer rides
because it lacks stability and support.
The search for the perfect saddle is elusive. What may work for one rider may
not work for another. So many factors are involved that it is unlikely one
saddle will work for everyone. The conventional wisdom in the biking world is to
experiment with saddles until you find the one that works best for you.
Can women get perineal symptoms?
Yes. In a study of 282 female members of a
cycling club, 34% reported perineal numbness. The researchers pointed out that
this is due to the fact that certain parts of the female and male anatomy are
similar, particularly the vessels and nerves in the perineum.
Can I get perineal symptoms from spin class?
I am not aware of any research
that addresses this question, but it makes sense that you could be at risk since
spinning isn't different than outdoor biking in terms of pressure on the
perineum. With that in mind, make sure to adjust your seat height properly (ask
your instructor if you're not sure how), and wear bike pants to cushion the
perineum from saddle forces.
What can be done to prevent perineal symptoms?
The variables that contribute
to perineal symptoms during biking are complicated, and so it may be that you
need to experiment with different strategies until you find the right one for
you. Here are a number of suggestions that may help reduce the risk of perineal
1. Stand up frequently on the pedals to take pressure off the
2. Change your position on the saddle while biking. Shift forward and
backward when you ride to eliminate pressure on just one part of the perineum.
3. Experiment with adjusting the angle of your saddle so that it tilts slightly
4. Wear bike shorts. They have chamois padding in the perineal area
that will help relieve pressure.
5. Adjust the height of your handlebars
slightly until you find a comfortable position. Handlebars below the saddle may
work well for road or racing bikes, but perhaps not as well for touring or
6. Make sure that your seat post is adjusted to the proper height. Your
knee should be just slightly bent at the bottom of the pedal cycle.
7. Limit the
number of miles that you pedal. This may not be desirable for all riders, but
number of miles per week can be a factor.
The final word
Many factors can contribute to perineal symptoms, and you will
need to experiment with all of the factors mentioned in this article if you do
experience them. Of course, just because you bike doesn't mean that you will
experience perineal symptoms; in fact, many cyclists ride for years and never
experience any of them. But if you do, and they continue after you make
adjustments in your bike or riding style, then see your doctor because they
probably won't get better on their own if you continue to bike. In most cases,
perineal symptoms are not permanent and can be treated successfully.
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