Jim FixxA huge number of studies have shown that running helps to prevent heart attacks, so I couldn’t believe the news that running guru Jim Fixx had died of a heart attack at age 52 after his daily run in Hardwick, Vermont. He was the guy who made running popular, healthful, and desirable. He sold more than a million copies of his book The Complete Book of Running, published in 1977. He was a close friend and had been a guest on my radio show. At the time of his death, the whole country believed that running was healthful because Jim Fixx had transformed himself from an obese smoker into a svelte runner who appeared to be at the peak of health. On his many television shows and other public appearances, he would bring out his old pants with a waistband of more than 50 inches that could easily fit three men, and hold them up against his slim, muscular body.
Fixx started running in 1967 at age 35. At that time, he weighed 240 pounds and smoked two packs of cigarettes per day. Ten years later, when his Complete Book of Running was published, he had taken off more than 70 pounds and had given up smoking. He used himself as an example of how healthy a person can be after changing to a healthful lifestyle.  However, his autopsy showed that what was inside his body was much different from what appeared on the outside. The three main arteries leading to his heart were almost completely blocked with plaques, and his other arteries were filled with plaques as well.   The autopsy also showed that he had at least three heart attacks in the weeks before the one that killed him.
Jim Fixx was Probably a Diabetic
At that time I did not know, Jim Fixx did not know, and Jim Fixx’s doctors most likely did not know that Jim Fixx was probably an out-of-control diabetic.  If you take a look at the American Express commercial shot in 1979, five years before his death, you will see that he has a large belly and small buttocks.  Almost everyone who has these features is diabetic because they store most of their fat in their liver and a liver full of fat  is  a common cause of diabetes.  A high rise in blood sugar after meals causes high insulin levels and inflammation that punch holes in your arteries to cause plaques to form in arteries (Clin Chem, 2018;64:192–200), and heart attacks are caused by plaques breaking off from arteries.   When blood sugar rises after meals, your pancreas releases insulin that lowers blood sugar by driving sugar from the bloodstream into the liver.  However if the liver is full of fat, the liver does not accept sugar and blood sugar levels rise even higher to damage arteries, form plaques and then to break off the plaques to cause heart attacks.   Almost 50 percent of North American  adults are diabetic or pre-diabetic and more than 30 percent do not know that because their fasting blood sugars are normal.  If your fasting blood sugar is normal (<100), and your blood sugar is greater than 145 one hour after you eat a meal, you are diabetic and are at increased risk for a heart attack  (Diabetes Care,  October 2017).  That does not mean that you have to take drugs, but it does mean that you need a major change in your lifestyle.

Exercise Does Not Prevent Plaques
The world learned from Jim Fixx’s death that it takes more than just running marathons to prevent a heart attack.  A heart attack is not caused by narrowed arteries. It is caused by a sudden complete obstruction of all blood flow to the heart muscle that causes the heart muscle to die from lack of oxygen.  First a plaque breaks off from the inner lining of an artery leading to the heart and this is followed by bleeding and the formation of a clot that completely blocks all blood flow to the heart. Plaques are caused by a faulty diet, usually with lots of sugared drinks and foods, refined grains, red meats and processed meats (Journal of the American College of Cardiology, July 2017;70(4)).
Exercise does not prevent plaques from forming, but it can stabilize plaques so that they are far less likely to break off to cause a heart attack (Circulation, April 27, 2017;136:138-148; May 2, 2017;136:126-137).  A faulty pro-inflammatory diet is the major cause of plaque formation. Plaques start to form when blood levels of the bad LDL cholesterol exceed 50 mg/dl (J of the Am Coll of Cardiol, Dec 19, 2017;70:2979-2991) and almost all North Americans have blood levels higher than that.  You can tell if you have stable plaques that are not likely to break off to cause a heart attack by getting a CT scan of your arteries (American Journal of Roentgenology, March 2015;204(3):W249-W260).  If you have unstable plaques, you are at high risk for a heart attack. Your doctor is likely to prescribe an exercise program and you should restrict red meat and fried foods, avoid sugared drinks and sugar-added foods except during exercise, and eat plenty of fruits and vegetables. You should avoid being overweight, keep your blood levels of hydroxy-vitamin D above 20 ng/ml, and avoid smoking, second hand smoke and excess alcohol.
How Risky is Running a Marathon?
Fixx’s death scared runners around the world. Many had taken up running because they wanted to gain the health benefits that Jim Fixx appeared to have gotten from running.  Fixx had often quoted California pathologist Tom Bassler who said that any nonsmoker who could run a marathon in under four hours would never die from a heart attack. Jim Fixx ran his best marathon, a mediocre 3:15:54, in the 1974 Boston Marathon.  Tom Bassler compared marathon runners to the heart-disease-free Masai warriors and Tarahumara indians. In 1968, Tom Bassler was the respected editor of the American Medical Jogging Association. We communicated a lot because we both started our sons in running programs before they went to elementary school. His son finished a marathon at age four, and my son ran an age-group-world record 4:54 mile at age nine. Both kids quit running before high school, probably because they were tired of spending all their time running instead of playing.
The incidence of deaths over 23 years in the London Marathon is one out of sixty-seven thousand runners, or one death per two million miles run. In the New York City Marathon, three deaths occurred among 400,000 entries. Data from North America’s largest twenty 10 kilometer runs, ten 12 kilometer runs, twelve 15 kilometer runs and twenty half-marathon races showed five deaths from 1,636,720 race finishers. That’s one out of three hundred twenty three thousand, or 0.0003 percent. These figures were gathered and published by a good friend of mine, Dr. Lou Maharam (Phys Sportsmed, April 2004;32(4):33-40).
Ken Cooper and Nathan Pritikin Criticized Fixx’s Diet
I had dinner with Jim Fixx several times when we spoke at running clinics together, and he usually ordered a steak.   Dr. Kenneth Cooper, exercise physiologist and aerobics pioneer, reviewed Fixx’s medical records two years after his death and concluded that:
• Fixx had a horrible family history of early heart disease.  His father had a heart attack at age 35 and died of one at age 43.
• Fixx had been a heavy smoker and was under stress from a second divorce.
• Even though he had lost 70 pounds, he did not have a healthful diet.
Nathan Pritikin wrote in his book Diet for Runners, “Jim Fixx phoned me and criticized me for writing that many runners on the average American diet have died and will continue to drop dead during or shortly after long-distance events or training sessions.  Jim thought the chapter was hysterical in tone and would frighten a lot of runners. I told him that was my intention. I hoped it would frighten them into changing their diets. I explained that I think it is better to be hysterical before someone dies than after. Too many men, I told Jim, had already died because they believed Dr. Bassler when he said that anyone who could run a marathon in under four hours and who was a nonsmoker had immunity from having a heart attack. Six months later, a passing motorcyclist discovered a man lying dead beside a road in northern Vermont. He was clad only in shorts and running shoes. The man was Jim Fixx.”
We Owe Jim Fixx a Debt of Gratitude
Jim Fixx helped to foster the running boom.  Before him, many people including physicians felt that running was a waste of time, harmful and even dangerous.  Now we know that running can be an enjoyable, social exercise that can be part of a healthful lifestyle. When I used to run down the roads in the 1940s and 50s, people would stop me and ask me if I was boxer. That was ridiculous because I was six feet tall and weighed 120 pounds, but at that time, boxers were the only people who ran. Fixx changed all that.  Today, more than nine million North Americans compete in organized running events each year (RunRepeat.com, August 6,2021).
April 23, 1932 – July 20, 1984