What if all the training you do over 7 hours is making your heart and health worse not better? It’s possible.

Last week I published an article about the effects of alcohol on a cyclists’ body.

But what if I said the very thing we love doing is bad for us? That’s right cycling, or any endurance activity.

However, for the average fitness enthusiast, sport athlete, and fat-loss seeker, is lengthy and frequent training feasible and even necessary? Doubtful. Admit it: many dread initiating an training session or avoid it like the Swine flu for various and sundry reasons: difficult to schedule, not motivated, too time-consuming, and too physically demanding. Well, as I have mentioned in past articles, sensible exercise sessions do not need to be lengthy and performed every day. They do, however, require a certain level of physical effort. You cannot get something for nothing, because something must give.

But what about those who partake in extensive aerobic training? Well, here is a new controversy: too much “cardio” can damage the heart. Marathon runners are a good example of this. Although running a marathon is normally viewed as the essence of fitness and the ultimate test of endurance, it puts an unusual stress on the heart.

Dr. O’Keefe suggest that chronic training for, and competing in, extreme endurance exercise such as marathons, ironman distance triathlons, and very long distance bicycle races (Tour de France) may cause structural changes to the heart and large arteries, leading to myocardial injury.

Does cardio damage your heart?

The idea here is not to scare you, but rather just make you aware. The evidence is not conclusive, and there is no magic number of years or effort that the following information correlates to, but if you keep an eye on this material – then you will be better off.

Marathon runners are a good example of this. Although running a marathon is normally viewed as the essence of fitness and the ultimate test of endurance, it puts an unusual stress on the heart.

And here’s what they’re worried about, and what the study covers…

Their theory revolves around the idea that excessive cardio causes small amounts of damage in the short-term. Then these small injuries turn into more significant long-term changes that can hurt your heart, blood vessels, and even kill you.

This is thought to occur in a four step process:

  1. Endurance exercise places a higher than normal load on your heart. It increases your oxygen and energy needs. It raises stress hormones, heart rate, blood pressure, and strains the walls of your heart. It also causes oxidative stress and inflammation. The heart is starved for oxygen and overwhelmed with these demands, and in some cases is irreversibly scarred by the exertion.

  2. After each workout, your heart is tired from the effort and heart function drops. There are often changes in electrical activity, heart rate, and an increase in blood markers of heart damage. The inflammation and oxidative stress from the effort damages your heart, blood lipids, and blood vessels.

  3. With enough training, your heart increases in size, develops erratic electrical activity, loses some of its ability to function, and develops small patches of scar tissue that grow with more training. The blood vessels around the heart and throughout other parts of the body also become harder and develop thicker deposits of calcium and plaque.

  4. Over time, these long-term changes increase the risk of developing atherosclerosis, heart attack, coronary and peripheral artery disease, and in some cases, sudden cardiac arrest and early death.

Doing less than that is not considered to be harmful. So How Much is Too Much?

I imagine there are a lot of exercises can damage your heart under this theory, not just cycling. The study itself is based around running, and O’keefe suggests people don’t make a habit of running marathons. One thing I will point out is that O’Keefe talks about a greater risk to people over 45. Which for me comes back to the health scale, and why you ride. If you keep riding for a long time, I imagine that eventually you will be riding at 45 if you’re not there now. So it’s definitely something to keep in the back of your mind as the years tick away.

So if 3 or 4 hours may be dangerous – what’s the sweet spot? Keep in mind that yes he’s talking about running, it can easily be applied to cycling.

One of the best ways to do this is to follow a fitness regimen that mimics the movements of our hunter-gatherer ancestors. This includes short bursts of high-intensity activities and NOT long-distance running as per that required to complete a marathon or even an hour on the treadmill.