How does altitude affect performance – Letter to the Editor
It is so much more difficult to run at right altitudes than at sea level (where I train). Is there a way to calculate the performance effect of altitude on running?
Sam Pettway, Atlanta GA
Performance starts to be affected at about 1,000 meters altitude; the effect is not linear and the drop in performance is quite different for acclimated versus unacclimated individuals. A runner who is not acclimated will lose 10 to 12% in VO2max at an altitude of about 6,500 feet and 12 to 15% at 7,500 feet. However, performance will not be to the same degree because running economy is better at altitude (due to the less dense air resistance). Our research at 6,500 feet indicated a 12% loss of VO2max, but 6% improvement in running economy resulting in 6% loss in performance. The duration of a race is also a factor. An 800-meter race is so anaerobic that little performance difference exists. A 1,500-meter race may be six to 10 seconds slower, but over 20 seconds slower for unacclimated runners. An unacclimated runner could expect to lose a minute in 5K and as much as two minutes for a 10K
Jack Daniels, PhD, Cortland, NY
For the unacclimated individual, there is an additional issue beyond simple performance deficits: acute altitude sickness (AMS). AMS can occur in many at altitudes higher than 2,500 to 3,000 meters, which is lower than Pikes Peak. Endurance athletes are no less likely to experience this than sedentary individuals. Some people are more prone to AMS because they do not adapt readily to high altitude. The symptoms of AMS include nausea, vomiting, headache and severe fatigue–all of which would adversely affect performance.
Acclimatizing gradually (no more than an additional 300 meters per day above 3,000 meters) may help, as might several drugs, including acetazolamide and dexamethosone, but only under medical supervision.
Melvin Williams, PhD, Norfolk, VA
WHAT IS IT ABOUT GINGER ALE
Why do doctors often recommend ginger ale to combat dehydration during a bout of flu? Wouldn’t sports drink be better to hydrate and replace lost electrolytes? What is it about ginger ale–does it have real healing properties or are people who suggest it fixated on an old wives tale? How can anything carbonated be optimal for rehydrating? As a runner, I’m curious. You don’t see coaches and trainers making ginger ale available to athletes.
Matthew Nadal, Ridgemont, KY
Ginger has long been used for a wide variety of GI upsets, including colic, motion sickness, gas and morning sickness. Chinese medicine has incorporated ginger into many therapies for thousands of years. (As with any herb, be aware it is a drug and can have adverse reactions, particularly interfering with cardiac medications.) According to the Natural Medicines Comprehensive Database, ginger is possibly effective when used orally to prevent nausea, motion sickness, seasickness or morning sickness. Only ginger ale containing the natural constituents (gingerols) is effective.
Sarah Harding Laidlaw, MS, RD, Glade Park, CO
Yes, sports drink would be better. Some say ginger helps fight nausea, but how much ginger could ginger ale have? If it has any, not much, I bet. Maybe ginger ale is favored because it has less sugar (9.5%) and a lighter taste than some colas, and lacks caffeine. A little water never hurt anyone, but by and large, sports drinks rehydrate better than plain water, partly because their sodium helps keep absorbed fluid in the bloodstream. Carbonation is no big deal one way or the other, but some studies show that carbonation slows gastric emptying and so, as you suggest, is not optimal for rehydrating.
Randy Eichner, MD, Oklahoma City, OK
Ginger ale has twice the calories of a sports drink, and calories are also 4 important when you can’t keep things down. But for severe dehydration, oral rehydration beverages are available that are higher. In the 50s and 60s “Jamaica ginger” was listed as the third ingredient on Canada Dry’s ginger ale bottles. A recent tour of the supermarket, however, revealed that no current name-brand makers of the soda use ginger in their products. Ginger flavoring is not ginger! A Google search of the phrase “contains real ginger” resulted in only 11 hits none of which were ginger ale. Health food brands are your best bet. I found “ginger extract” listed as the third ingredient on a ginger beer in the health food store. Or, make it at home: http://biology.clu.uc.edu/fankhauser/cheese/Ginger_Ale_Ag0.htm
Jeff Venables, Editor
COMMUTING HAZARDS
I have been running for the past 25 years about 15 miles per week, mostly on a treadmill. Recently I started riding a bicycle to work. Unfortunately, I have also started having knee pain that seems like iliotibial band syndrome with pain on the outside of my right knee. Can bike riding cause this? What should I do?
John Tillman, Washington, DC
First of all, it is best not to guess when it comes to injury diagnosis and treatment. Mildly annoying problems can easily become chronic and interfere with your ability to continue running and cycling. If your problem hasn’t resolved after resting for a week or two, find a sports medicine professional for a thorough evaluation.
Assuming you are dealing with iliotibial band syndrome (ITBS), while it is most common among runners, it can also occur in cyclists. Cycling might also exacerbate an underlying, mild ITBS condition. The first thing you should do is find a professional bike shop and have your bicycle evaluated for fit. If your frame is too big or too small, or your seat adjustment is incorrect for your body, it can increase the stress and strain on both of your knees, hips and back.
Once you are certain your bike-fit is correct, you can minimize strain when riding if you avoid your big ring and stay in your saddle. When climbing hills, try spinning up rather than pushing a bigger gear. You will generate less force and will decrease the compressive load on your ITB at the knee.
As for recovery and future prevention, avoid running on a cambered surface (this doesn’t apply if you always run on a treadmill). Make sure you are wearing the right running shoes for your foot and running style, without excessive mileage. It is also very important to keep the ITB stretched from the hip to the knee. Stand with your left side about 12 to 18 inches away from a wall or other support, and cross your left foot in front of your right foot. Lean toward the wall, with your right arm straight up, pushing your right hip away, stretching your arm toward the wall, until you feel a stretch from the hip downward. Hold for 30 seconds and repeat on the other side.
Pain can be minimized with massage (manually or by rolling on your side on a styrofoam roll), icing, stretching and topical anti-inflammatories (ask your pharmacist about these). It can be helpful to strengthen the gluteal muscles, particularly the gluteus medius, which is primarily responsible for abduction (moving the leg laterally away from the body), and is important in controlling pelvic motion. This may, in turn, reduce the tension on the ITB from above. To strengthen hip abduction, while lying on your side with the affected leg up and weight applied to the ankle, slowly lift (abduct) the leg and slowly lower it.
John Cianca, MD, Houston, TX
RUNNING AND EYE PRESSURE
This may be a bizarre question, but can training affect the pressure of my eyes? My grandmother has glaucoma, and my eye pressure readings are on the high side. I am a 33-year-old female, 5 feet tall, 110 lbs. I run 30 miles a week, and I’m also a triathlete. I have an eye appointment scheduled, but I thought I’d ask anyway.
Pamela Congemi, Metairie, LA
It isn’t a bizarre question at all. Since fitness and cardiovascular health can improve blood pressure, it is only natural to think it might affect intraocular pressure (IOP) as well. Yet, it doesn’t. Neither does stress or diet. Very little effects IOP, and running (or swimming or biking) will not harm the eyes in any way. There is data from the Ocular Hypertensive Treatment Study to suggest that we may need to treat patients with elevated IOP earlier than in the past, even if they have no other signs of glaucoma. Therefore, it’s good you’re scheduled for a check-up.
David S. Hays, OD, University Place, WA
Studies have shown that running and other forms of vigorous exercise do lower IOP for one, perhaps two, hours. This is temporary and exercise alone is not sufficient treatment for glaucoma, though runners do have healthier blood vessels in the eye and probably fewer cataracts.
John C. Hagan III, MD, Kansas City, MO
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