By Dr. Mercola
Completing a marathon is thought of by many as the epitome of health. But every year there are reports of people dropping dead before they cross the finish line.
Most recently, a healthy 30-year-old who was running the London Marathon to raise money for an organization that helps prevent suicides collapsed about a mile short of the finish line; medics were unable to revive her.
Such deaths, though uncommon, are not unheard of.
Eleven runners have died while running the London Marathon since it began in 1981, and every year a handful of runners die while competing in such events (one study put the rate of sudden cardiac deaths during a marathon at 0.8 per 100,000 participants1).
What's going on in these cases? Is marathon running really as "healthy" as it's made out to be?
Why do People Die While Running Marathons?
Heatstroke can certainly be a factor, as can hyponatremia -- low sodium levels in the blood often caused by drinking too much water during exercise. However, in the vast majority of cases, people die during marathons because of a heart attack. Marathon running puts an extraordinary stress on your heart, one that your body was not designed for.
It's a classic example of a concept known as "the reverse effect" – where too much of something that is normally good for you can have the opposite impact. According to a study presented at the Canadian Cardiovascular Congress 2010 in Montreal, regular exercise reduces cardiovascular risk by a factor of two or three.
But the extended vigorous exercise performed during a marathon raises cardiac risk by seven-fold!2 Researchers found that during a marathon more than half of the segments in your heart lose function due to an increase in inflammation and a decrease in blood flow, and this temporary heart damage may play a role in marathon deaths.
Research by Dr. Arthur Siegel, director of Internal Medicine at Harvard's McLean Hospital, also found that long-distance running leads to high levels of inflammation that may trigger cardiac events,3 and a separate study published in Circulation found that running a marathon lead to abnormalities in how blood was pumped into the heart.4
There's now overwhelming evidence indicating that conventional cardio or long-distance running is one of the worst forms of exercise there is, and even if you're one of the lucky ones who does not end up suffering from a sudden cardiac event in the middle of a race, in the long run your heart health can still suffer.
Long-Distance Running Damages Your Heart
Do you pride yourself on running mile upon mile, week after week? Do you love the challenge and adrenaline rush that comes from completing a marathon?
Let me preface the information that follows by saying this: as a former sub 3-hour marathon runner myself, I understand the drive that pushes many athletes and weekend warriors to compete in these strenuous events. But now that I have examined the research, I firmly believe doing so may put your heart at risk. For example, two recent studies showed:
- Heart damage after lifelong cardio: In a study published in the Journal of Applied Physiology,5 researchers recruited a group of extremely fit older men. All of them were members of the 100 Marathon club, meaning athletes who had completed a minimum of 100 marathons. If running marathons provided cardiovascular benefit this would certainly be the group you would want to seriously examine. So what did they find?
Half of the older lifelong athletes showed some heart muscle scarring as a result, and they were specifically the men who had trained the longest and hardest.
- Heart scarring after elite cardio training: An animal study published in the journal Circulation6 was designed to mimic the strenuous daily exercise load of serious marathoners over the course of 10 years. All the rats had normal, healthy hearts at the outset of the study, but by the end most of them had developed "diffuse scarring and some structural changes, similar to the changes seen in the human endurance athletes."
Is There a Better Way to Exercise?
Science now suggests that the best fitness regimen is actually one that mimics the movements of our hunter-gatherer ancestors, which included short bursts of high-intensity activities, but not long-distance running such as is required to complete a marathon. The idea behind "hunter-gatherer fitness" is to closely emulate the actions that ancient man took on a daily basis. This is what your body is hard-wired for, after all, and includes such attributes as:
- A variety of exercises performed regularly (weight training, cardio, stretching, etc.)
- Alternate difficult days with easier days
- Interval training sessions performed once or twice a week
- Weight training at least twice a week
- Ample time for rest after physical exertion
Your exercise program should be challenging, as it was for our ancestors, but it should not be excessive and it should be paired with ample time for recovery. Just as too much strenuous exercise can hurt your heart, too little will not be enough to give you the benefits.
The good news is, the most recent research shows that relatively short bursts of intense exercise—even if done only a total of a few minutes each week—can deliver many of the health and fitness benefits you get from doing hours of conventional exercise.
By doing just three minutes of High Intensity Training (HIT) like Peak Fitness a week for four weeks, you could see significant changes in important health indices. You don't even need a gym to perform high-intensity interval exercise. It can be performed with virtually any type of exercise, with or without equipment. You can just as easily perform interval training by walking or running outdoors as you can using a recumbent bike or an elliptical machine.
While it's theoretically possible to reap valuable results with as little as three minutes once a week, it might be more beneficial doing them two or three times a week for a total of four minutes of intense exertion, especially if you are not doing strength training. You do not need to do them more often than that however. In fact, doing it more frequently than two or three times a week can be counterproductive, as your body needs to recover between sessions.
One of my favorite new ways of doing high-intensity exercise is sprinting on the beach, and I actually am in the process of completing a video on that. But if you do sprinting be very careful to always stretch your hamstrings first. Stretching is NOT optional if you are going to sprint, as there is a high likelihood you will injure yourself. I demonstrate a very effective stretching program on the video but in the meantime you can view my elliptical Peak Fitness video to get an idea of how hard you need to work out.
Proper Intensity is Key
I personally do Peak Fitness on an elliptical, or sand sprints, once a week and currently, twice a week, I am doing a fairly intense strength-training workout. If I feel that I have plenty of energy and can complete the workout, then I continue in that frequency, but if I get tired and poop out during the session, I know it is time for me to increase my recovery time. In that case, I decrease strength training to once a week and put more time in on the Power Plate.
If you want to do more, focus on making sure you're really pushing yourself as hard as you can during those two or three weekly sessions, rather than increasing the frequency. Intensity is KEY for reaping all the benefits interval training can offer. To perform it correctly, you'll want to raise your heart rate to your anaerobic threshold, and to do that, you have to give it your all for those 20 to 30 second intervals.
Here's a summary of what a typical interval routine might look like using an elliptical:
- Warm up for three minutes
- Exercise as hard and fast as you can for 30 seconds. You should be gasping for breath and feel like you couldn't possibly go on another few seconds. It is better to use lower resistance and higher repetitions to increase your heart rate
- Recover for 90 seconds, still moving, but at slower pace and decreased resistance
- Repeat the high intensity exercise and recovery 7 more times
When you're first starting out, depending on your level of fitness, you may only be able to do two or three repetitions of the high intensity intervals. As you get fitter, just keep adding repetitions until you're doing eight during your 20-minute session. You will notice that the Peak Fitness has 30 seconds rather than 20 and goes for 8 sessions so it is a harder workout.
By exercising in short bursts, followed by periods of recovery, you recreate exactly what your body needs for optimum health. The beauty of Peak Fitness is that you don't have to worry about traditional cardio like long-distance running because you're going to get those cardio benefits (and more) through this program, but without risking sudden or long-term damage to your heart.
This program much more closely replicates the fitness regimen of our ancestors … and when combined with the other facets of the Peak Fitness program -- strength training, stretching and core work – is one of the best workout routines there is.