As you have probably read or heard, America has a weight problem. Sometimes the statement is made that a person is fit and fat. I see some people that might be in this category on some of the rides I go on. I try to think of how these people may be in this condition and how they can remain that way while riding as much as they may claim.

My favorite health and fitness doctor had an article in his recent email newsletter that touched on this subject. Dr. Mirkin had this to say,

“Obesity and High-Fat Diets Interfere with Muscle Growth.

An editorial in The Journal of Physiology explains how both high-fat diets and obesity prevent strength gain with exercise, and increase risk for diabetes heart attacks, and premature death (1).

The editorial was inspired by a study from the University of California at Davis, showing that a high-fat diet prevents exercising mice from enlarging their muscles (2) . If this study can be applied to humans, it means that not only does a high-fat diet make you fatter, it also prevents you from enlarging your muscles.”

You can read the full article at www.drmirkin.com.

According to an article from Dr. Gabe Mirkin, eggs do not cause heart attacks. He cites “the Physician’s Health Study followed doctors for 20 years and showed no association between eating eggs and heart attacks or strokes.  However, the doctors who ate lots of eggs did die earlier than those who avoided eggs, possibly because they also ate more bacon, sausage and butter.”

The question is the statement at the end that possibly the stuff we eat with eggs causes the problem with dietary cholesterol. While I have enjoyed fried, scrambled and poached eggs in the past I do not make them part of my regular diet now. Once in awhile my wife likes to have an egg burrito and I do partake though. I generally eat lots of vegetables, fruit and no red meat. Fish tacos are a new found item. My cholesterol is usually below 140.

Read Dr. Mirkin’s full article here.

For example, the Physician's Health Study
followed doctors for 20 years and showed no association between
eating eggs and heart attacks or strokes.  However, the doctors
who ate lots of eggs did die earlier than those who avoided eggs,
possibly because they also ate more bacon, sausage and butter.

I was reading over the New York Times and starting reading an article by Gretchen Reynolds titled “Bones?Is Bicycling Bad for Your “. Ms. Reynolds writes about a study Aaron Smathers did that sudied bone density amongst cyclists and compared the results to other sports participants. I have posted information about this subject previously from Dr. Mirkin.

Thinking of this from what I know about metals, density is not the only factor one has to consider when comparing strengths and characteristics about materials. Much like bike frame materials, our body’s frame has many properties that just one measurement does not describe.

Aaron Smathers observed first hand from crashes he experienced but I was somewhat wondering why he was racing just six weeks after breaking his collarbone.

It’s summer and in Texas that means lots of sun and this year even more than usual. In southeast Texas we have been setting temperature records which means plenty of sun. My dermotologist recommends at a sunscreen with a SPF55 or more. The only one I have found with this number or more is Neutrogena UltraSheer Dry Touch Sunblock. I found this at Wal-Mart in a 3.0 ounce tube for $9.92. This sunblock is up to the Texas heat and humidity.

from www.drmirkin.com

• Non-melanoma skin cancer risk (basal and squamous cell skin cancers) is increased by cumulative sun exposure over a lifetime.

• Recent data show that a single sunburn may cause a melanoma.

• It appears that blond and blue-eyed people need less sun exposure to make vitamin D. People with dark skin, or those who become very dark when they tan need far more sun exposure to make vitamin D.

Dr. Mirkin writes:

Hip Fracture Usually Requires Hip Replacement

The most-feared injury among serious bicyclists is a broken hip. The femur hip bone is shaped like a shepherd’s crook. The blood supply to the ball at the top of the hip bone comes in through the neck just below the ball. If the neck or ball are broken, the blood supply is usually shut off and the top of the hip bone dies.  To prevent this from happening, fractures of the ball or neck of the hip bone are usually treated with immediate hip replacement.  Try to avoid this drastic surgery by keeping your bones as strong as possible.

1) All exercise strengthens bones.  Bicycling strengthens bones, but not as much as sports that exert greater forces on bones such as running or lifting weights. (Medicine & Science in Sports & Exercise, March 2009).
2) Exercise increases calcium absorption, which is necessary for strong bones.

Read points 3 and 4 at www.drkirkin.com

Dear Dr. Mirkin: Won’t I be a better bicycle rider if I ride hard every day?

If you exercise intensely when your muscles are sore, you put yourself at high risk for injury. The soreness you feel is from
direct muscle damage. Putting great pressure on damaged muscles causes them to tear.  Furthermore, sore muscles significantly
increase your needs for oxygen during exercise and slow you down (European Journal of Applied Physiology, March 2009).  That’s why athletes in every sport use the “hard-easy principle.”  To become a better rider, do a hard session (very fast and/or lots of hills)
so your muscles feel sore on the next day.  Go slowly for as many days as it takes for the soreness to disappear, and then take
another hard day.

http://www.drmirkin.com

Today’s email newsletter from Dr. Mirkin describes his experience with large doses and small doses of vitamin D and how this affect sore muscle recovery. Link to Dr. Mirkin’s website.

From the newsletter:

When doctors don’t know the cause of a patient’s problem, they often give it a fancy name so you will believe they are giving you a useful diagnosis.  A perfect example of this is “idiopathic inflammatory myopathy”, which means you have chronic muscle soreness and your doctor doesn’t know why. Researchers recently reviewed the effects of exercise on people with chronic muscle soreness and found that exercise is beneficial (Current Opinion in Rheumatology, 04/07/09):
*The muscles of many of subjects with this condition did not get a sufficient oxygen supply
*Exercise increases endurance-type fibers after a 12-week exercise program
*Creatine supplements plus an exercise program are more beneficial than exercise alone
*Intensive resistance training improves muscle strength and endurance
*Exercise reduces muscle soreness and possibly even muscle inflammation
I am now convinced that a leading cause of muscle soreness and slow-healing injuries is lack of vitamin D.  All my life, I have suffered a series of baffling injures that usually occur in the winter. and heal in the summer.  For the entire winter of 2007-8, I was unable to exercise because of a non-healing hamstring injury and diffuse muscle soreness.  Eventually I found that my vitamin D 3 level was 22 nmol/L (normal is greater than 75).  I took the prescribed treatment of 50,000 IU of vitamin D twice a week and my muscles became so sore that I couldn’t even walk.  In the summer, the hamstring injury healed and the soreness disappeared.  This winter I went to Florida and was able to train on my bicycle better than ever.  In March I went back to wintery Maryland and the non-healing hamstring injury and soreness reappeared.  This time I improved within 24 hours of taking 2000 IU of vitamin D twice a day.  From my experience, I conclude that:
* my muscle soreness and non-healing injuries are caused by or worsened by low levels of vitamin D
* very high doses (50,000 IU) may increase muscle soreness
* lower doses of vitamin D (2000 to 4000/day) or daily sunlight exposure cured my muscle soreness and helped to heal my injuries
Dr. John Cannell of the Vitamin D Council quotes 14 studies that show that athletic performance improves in the summer
months when sunshine is abundant, or with ultraviolet light exposure in winter. http://www.vitamindcouncil.org/newsletter/2007-mar.shtml
If your muscles feel sore or you keep on being injured when you exercise, get a blood test called D3.  If it is below 75
nmol/L, your problems may be caused by lack of vitamin D and be cured by getting some sunshine or taking at least 2000 IU each
day of the very inexpensive vitamin D3.

Since I fall in this category I am very interested in this subject. An excerpt from Dr. Mirkin’s latest post:

“Men who start or increase their exercise programs after age fifty live longer than those who remain at their present activity levels, according to a study in the British Medical Journal (March 2009). More than 2200 men were checked at ages 50, 60, 70, 77 and 82 years. The greater the increase in exercise duration over that span, the longer their lives were extended. The reduction in early death from increasing exercise was the same as for men who stopped smoking.”

Link to Dr. Mirkin’s full post.

from www.drmirkin.com

“Sprint cyclists, and to a lesser extent distance cyclists, had greater tibia and radius bone strength surrogates than the controls, with tibial bone measures being well preserved with age in all groups.
This suggests that competition-based cycling and the associated training regimen is beneficial in preserving average or above-average bone strength surrogates into old age in men” (Medicine & Science in Sports & Exercise, March 2009).

Several readers responded, quoting other studies that showed competitive cyclists have lower bone mineral density in their spines than moderately-active, aged-matched men (Medicine and Science in Sports and Exercise,  February 2009;  Osteoporosis International Reports, August 2003). These studies have been interpreted to mean that cycling increases risk for bone fractures beyond what you would expect from just falling off the bike.

I cannot find any studies showing that cycling weakens bones to increase fracture risk.  Bone density is associated with bone strength, but does not measure it.  The only way to measure bone strength is to see how much force it takes at break a bone. For example, birds have strong bones that are not very dense.

The theory that the act of cycling weakens bones flies in the face of our current understanding of bone metabolism. If indeed cyclists suffer from weak bones (and I do not believe that they do), the cause would be something other than riding a bicycle.   Bones are constantly remodeling. Cells called osteoblasts bring in calcium to bones while cells called osteoclasts take calcium out. Any force on bones increases, and lack of force decreases, the rate of bone formation. Astronauts in space lose bone because lack of force blocks their ability to respond to Insulin Like Growth Factor-1 that stimulates bone growth (Journal of Bone and Mineral Research, March 2004).   All competitive cyclists know that hammering on the pedals while pulling up on their handle bars puts tremendous force on every muscle and bone in their bodies, and this should stimulate bone growth.

==========================

Update (3/6/09)

I was reading the latest edition of RoadBikeRider.com Newsletter (Issue No. 383 – 03/05/09) where I found this dissenting view on Dr. Mirkin’s article.

ED’S NOTE: I was stunned late last week to read this Q&A in the widely circulated medical newsletter by Gabe Mirkin, M.D., a doctor in his 70s who does about 200 miles (320 km) a week on a tandem and in spirited group rides.

Q:  Does bicycling reduce bone density, increasing risk for fractures and osteoporosis?

Dr. Mirkin: “This is a myth that is not supported by any good data. A study from Manchester Metropolitan University in the UK shows that sprint cyclists have denser bones than long distance cyclists, who have denser bones than sedentary control subjects (Medicine & Science in Sports & Exercise, March 2009).

“While cyclists have less dense bones than weight lifters and football players, they still have denser bones than people who do not exercise. The greater the force on bones during exercise, the denser the bone. So any type of exercise is good for your bones and a sedentary lifestyle is bad for bones.”

I can agree with some of that, but the first sentence is outrageous. One study that produces differing evidence does not make a “myth” out of all that’s come before.

In fact, a different issue of the journal cited by Dr. Mirkin reports a study that found competitive male road cyclists had significantly lower bone mineral density in their spines than a control group of men who were moderately physically active. Even though the cyclists had a greater calcium intake, they were still more likely to have osteopenia (lower-than-normal bone density) or osteoporosis (very low bone mineral density) than those in the control group.

A report about this by Newswise is found at http://tinyurl.com/cmj67x. It includes this interesting note, “A similar study in Bone illustrated that male road cyclists had lower bone mineral density than male mountain bikers after adjusting for body weight and age. The distinction could be found in that mountain biking, with its variable terrain, provides more impact for bone growth than road cycling or racing.”

The report adds, “When it comes to the risk of thinning bones, however, it’s the weight-bearing nature of exercise that signals bones to create more mass. Without such stress, bones do not get stronger, and become more prone to injury.”

Cycling isn’t very weight-bearing. I wish I could cite the source, but I recall reading that when spinning along at 90 rpm — typical cruising conditions — a cyclist exerts only about 14 pounds of force on the pedals, often less. Someone running, however, experiences 3 times body weight on each footfall.

Personally, my list of physical imperfections includes osteopenia, diagnosed in the early 1990s after road cycling had been my primary sport for most of the preceding dozen years. When RBR polled male subscribers a few months ago, 1 in 10 said they have been diagnosed with osteopenia or osteoporosis — the “old ladies’ disease.” Twenty-four percent said they were concerned enough about bone density to seek a DXA scan.

Diet, age and heredity also play roles. So it’s a complicated issue. But it’s not a myth that cyclists as a group have been found to suffer from low bone density. I sent that objection to Dr. Mirkin and asked him to respond.

Here’s what he wrote back: >>>SOS

Two Houstonians joining Team Sun & Ski for the MS 150′s 25th anniversary who are workout partners who began training Jan. 6, 2009 as a weight loss challenge and to raise awareness and funds for multiple sclerosis (MS.)

Wayne Dolezal (77077)  and Anna Rocha (77012), who each weighed in Tuesday, Jan. 6 at 270 pounds, are training for the MS150 as a way to both support MS and to start the New Year with healthy, physically fit lifestyles. They will have their March weigh-in today at 4:15 p.m.

Wayne says he personally averages cycling 50 to 70 miles a week, and he and Anna have logged about 1,000 miles together in the two-month training period, including one 90-minute spin class per week (Wednesday evenings at Sun & Ski Sports, 6100 Westheimer) and training rides in Katy every Saturday. Wayne’s blood pressure has radically decreased, along with his resting heart rate, He says he was able to purchase designer jeans in a specialty shop for the first time ever without going to a “Big Boys” wholesaler, “so that’s cool!”

Our heart rate monitors are assisting us in tracking progress toward our attainable heart rate goals, while tracking calories burned at the same time. Last week during spin class at Sun & Ski, Wayne expunged 1,600 calories in one class. To put that into perspective, if he never changed anything about his diet, he could lose 50 pounds a year if he did spinning at that level twice a week… “Spin class is awesome!” Anna’s 44-mile ride in the “Spring Breakaway” (against the wind) burned 3,000 calories.  That was 3.5 hours of pure workout right there!

Their MS 150 cycling coach is Steve Moskowitz,  Conoco Phillips MS 150 Team Captain. Their fitness coach is Mark Leblanc, president of the WELLFIT Group.

Wayne will be riding the MS 150 in honor of a friend’s daughter, Steph, who has MS.  Wayne explained, ”I became aware of the disease from a friend’s daughter, who was diagnosed with MS four years ago at the age of 19.  Steph lives a healthy lifestyle, is a good person, and still she has the random disease of MS.  She began riding in the MS 150 3 years ago, and is a true champion for the cause.  Steph does everything she can with medication, exercise, and diet to fight the effects on a daily basis.  Her resilience is, and will always be, an inspiration to me.  I hope that, with the help of Sun and Ski, I can both lose weight as well as raise money for a great organization to help the tens of thousands of Americans living with MS.”