Is cardio exercise a killer?

Over the last few years, there has been a number of articles covering the research that shows too much cardio can damage your heart. The trouble with all this information flying around the media is that it can be misleading and scare people away from much needed exercise.

This week, let's put a little perspective to the facts around cardiovascular exercise. What is cardio? Cardio or aerobic exercise is any steady state of locomotion that increases a person's heart rate for 20 minutes or more. Common types of cardiovascular exercises are walking, running, cycling, swimming and jogging. Here are just a few common negatives that come with cardio or aerobic exercise:

* Cardiovascular exercise causes oxidative stress. A rough definition of oxidative stress from exercise is that contracting skeletal muscles generate free radicals and prolonged and intense exercise can result in oxidative damage to cells. Oxidative stress can be the cause of many diseases... so many that the information would exceed my column's limit.

* Cardiovascular exercise causes scarring of the heart tissue which can lead to an irregular heartbeat and death.

* Cardiovascular exercise decreases testosterone: Some studies have reported that long distance runners have shown a reduction in testosterone.

* Cardiovascular exercise causes chronic fatigue and adrenal burnout: Excessive exercise stresses the body's systems and does not allow the body to recover properly, creating potential fatigue related issues.

* Cardiovascular exercise causes stress injuries to the feet, ankles and knees.

* Cardiovascular exercise creates a pro-inflammatory response in the human body that leads to a number of chronic illnesses.

I am sure many of you have heard about one or all of these points. I am also pretty sure the people that do not like any form of cardio or aerobic exercise will say, "See, I always told you that stuff is killing you." Recently, the media and some health professionals have started to take a harder look at a number of new studies that have concluded that long-term endurance training can damage your heart. In one such study, researchers indicated that specifically men who competed in marathons over the course of 26 years are more likely to have more build up of coronary plaque which can lead to heart arrhythmia. In another study, it was shown that long-term elite cyclists are more likely to develop ventricular tachycardia. In yet another documented case study, it showed that long-term endurance athletes suffer from a decrease in their right ventricle function after competitive endurance events. Many long-term endurance athletes also have increased blood levels of cardiac enzymes which can be an indication of damage to the heart tissue.

The most recent and most referenced study that came out earlier this year was published in the Journal of Applied Physiology. This study looked at varied age groups from mid-20s up to 67 years old. The researchers focused on 20 fit men older than 50 as the control group and ensured that they where all members of the 100 Marathon Club. These men had spent much of their life doing extensive endurance training to compete in a large number of marathons. What the bottom line of the research showed was younger men and men who did low level training had normal heart scans. The control group did, however, show that about half the men had signs of fibrosis, or scarring, within the heart muscle. Face value of all this research can be disturbing to the uninformed, but for the vast majority of us, this information should not be taken as a message to stop or curb our overall fitness programs.

When it comes to research and studies on fitness or nutrition that can have a negative impact on our health, the media loves to push the message out there. Most of the time the data from these studies is difficult to understand, and in most cases studies have so many variables tied to them that cause and effect becomes blurred by the media.

When it comes to best practices for cardiovascular benefits without potential long-term heart damage, the following should be considered:

1. First and foremost, endurance training should be approached with moderation in mind. When it comes to endurance training, we are not all created equally so start slow and build to a comfortable level without it becoming excessive.

2. Incorporate HITT high intensity training, which gives your body the ability to build good endurance and strength with more recovery in between the short bursts of intense cardio.

3. Limit your training days and allow time for recovery. Some of the very best elite athletes in the world manage their training time with precision. They know recovery is the most important aspect along with solid nutrition to build to peak performance.

4. Listen to your body, the old saying "no pain no gain" is not the right approach. Your body speaks to you everyday. It is critical to be very aware of your aches, pains, hydration levels. Also be mindful of your nutrition needs so your body can be very responsive to increased fitness levels.

5. Use a simple progression approach that allows enough time for your endurance and performance to improve and at the same time, lets your body help and strengthen without too much stress and high cortisol levels.

6. Work with your doctor, get yearly physicals, do regular checkups. Be very clear with your doctor on your fitness levels. He or she may run tests to ensure your heart is running at peak levels.

Overdoing exercise regardless of the type can damage your health. Stay on top of your workout regimens and keep in mind that rest and recovery is key to building up your fitness. Do not overreact to media reports that state "New findings, cardio can damage your heart" too much of anything can be harmful. Also, keep in mind that for most of us, we will never overexercise to the point of damaged organs or heart muscle. Who has that kind of time?

Most of us do not exercise enough, so don't stop. Just use your head when building your fitness program.

Judd Jones is a director for the Hagadone Corporation.