Endurance exercise – Is it safe?

From the studies listed closely below, endurance based activities are probably quite dangerous for the average and elite athlete. Cardiac damage and electrical heart arrhythmias are certainly common amongst many elite athletes, with ex World Champion Pro Athletes Greg Welch and Emma Carney from the triathlon world being the best examples (both stopped due to life threatening cardiac conditions). The listed studies are a great example of why at the Nepean Naturopathic Centre we harp strongly on the necessity of supplementary nutrition to protect against the types of problems mentioned and many more. Supplements that are anti-inflammatory and antioxidant are prescribed to protect from DNA damage, mitochondrial impairment, immune compromisation, muscular injury, oxidative stress and neurological reparation…

Exercise is important, but treating your body properly to train safely is even more important…. The fact that these supplements aid in not only in health, but also endurance sport is mainly due to the regulation and protective mechanisms activated on a DNA, cellular and systemic level through the action of these primarily plant based medicines. Supplements such as the B vitamins, Vitanox, Withania Complex, Rhodiola Ginseng, PhytoRegenex, Livton, Poly C and Q10 are prescribed to many patients for protection and wellbeing; however for athletes, it is even more important for long term health, not just your next feat… Ferrari performance requires maximal supplementation for Ferrari results… Food is not enough alone!!!Triathlon

Further down I have attached some studies to show why these products are prescribed. If I got really serious, I could fill books, but there are enough examples there to get the gist along with our other articles on the website.

 Endurance exercise and the dangers…

1. 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 your cardiac risk seven fold!
2. In a 2011 study published in the Journal of Applied Physiology, researchers recruited a group of extremely fit older men, all members of the 100 Marathon club (having completed a minimum of 100 marathons). Half of the men showed heart muscle scarring as a result of their endurance running—specifically, the half who had trained the longest and hardest. If running marathons provided cardiovascular benefit, this group would have had the healthiest hearts!
3. A 2011 rat study published in the journal Circulation 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.”
4. A 2012 study in the European Heart Journal found that long-term endurance athletes suffer from diminished function of the right ventricle of the heart and increased cardiac enzymes (markers for heart injury) after endurance racing, which may activate platelet formation and clotting. Twelve percent of the athletes had detectable scar tissue on their heart muscle one week post-race.
5. A 2010 study presented by the American College of Cardiology showed that endurance runners have more calcified plaque in their arteries (which also increases stroke and dementia risk) than those who are not endurance athletes.
6. A 2011 German study revealed a very high incidence of carotid and peripheral atherosclerosis among male marathon runners.
7. A 2006 study screened 60 non-elite participants of the 2004 and 2005 Boston Marathons, using echocardiography and serum biomarkers. Researchers found decreased right ventricular systolic function in the runners, caused by an increase in inflammation and a decrease in blood flow.
8. 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.

Sustained Elevated Cardiac Output Can ‘Tear Apart’ Your Heart Tissue

As you can see from the above studies, the research is converging around the considerable
risks that high endurance cardio-type exercises pose for your heart. When you engage in this type of training, your heart doesn’t have much say in the matter, as it simply responds to biochemical signals from your body to ramp up cardiac output in order to keep up with your level of exertion. You can’t “feel its pain” until very late in the game, and at that point, it may be a life-threatening situation.

Extreme exercise causes your heart to massively increase cardiac output, which it may have to sustain for several hours, depending on the duration and intensity of your activity.

Your heart pumps about five litres of blood per minute when you’re sitting. But when you’re running, it goes up to 25 to 30 litres, and it wasn’t designed to do this for hours on end, day after day. It enters a state of “volume overload” that stretches the walls of your heart muscle, literally breaking fibres apart.

The problem is, many endurance athletes don’t allow their bodies to fully recover between sessions. They often live in a perpetual post-workout state, which basically resembles chronic oxidative stress. Repeated damage to the heart muscle increases inflammation which leads to increased plaque formation, because plaque is your body’s way of “bandaging” the lining of your inflamed arteries.

Over time, as more damage is inflicted, the heart enlarges (hypertrophy), and forms scars (cardiac fibrosis). MRIs of long-time marathoners reveal abundant scarring all over their hearts. Scientists have also measured elevated cardiac enzyme levels after extreme exercise—just like after a heart attack, which can only mean one thing: this type of exercise is damaging people’s hearts.

Endurance Training Can Produce Dangerous Arrhythmias, Myocardial Fibrosis, Hypertrophy and Atherosclerosis

Although researchers don’t yet understand all of the factors in this process, they have theorized that high endurance exercise leads to cardiac fatigue, then a flood of catecholamines and adrenalin, which then triggers arrhythmias (abnormal heart rhythms). One common arrhythmia is atrial fibrillation, commonly known as “A-fib.” A-fib is epidemic among endurance athletes, which sets them up for major increase in stroke risk. Marathoners above age 50 have a five-fold increase in A-fib rates.

Arrhythmias can progress into full cardiac arrest. According to Dr. James O’Keefe, a research cardiologist and former elite athlete, 50 percent of marathon deaths occur in the final mile of the race, probably due to this cumulative stress on the heart. Dr. O’Keefe summarizes the entire phenomenon nicely in his Mayo Clinic Proceedings paper:

 “Emerging data suggest that chronic training for and competing in extreme endurance events such as marathons, ultramarathons, ironman distance triathlons, and very long distance bicycle races, can cause transient acute volume overload of the atria and right ventricle, with transient reductions in right ventricular ejection fraction and elevations of cardiac biomarkers, all of which return to normal within 1 week.

 Over months to years of repetitive injury, this process, in some individuals, may lead to patchy myocardial fibrosis, particularly in the atria, interventricular septum, and right ventricle, creating a substrate for atrial and ventricular arrhythmias. Additionally, long-term excessive sustained exercise may be associated with coronary artery calcification, diastolic dysfunction, and large-artery wall stiffening.”

A sample of protective studies.. (edited extracts)

J Med Food. 2010 Feb;13(1):211-5.

Antifatigue effect of coenzyme Q10 in mice.

Fu X, Ji R, Dam J.


Department of Women’s and Children’s Health, Obstetrics and Gynaecology, Uppsala University, Uppsala, Sweden.


The aim of this study was to investigate whether coenzyme Q10 (CoQ10) has an antifatigue effect in mice. ICR male mice were orally given CoQ10 in the form of Bio-Quinone (Pharma Nord, Vejle, Denmark) at doses of 0, 1.5, 15, or 45 mg/kg/day for 4 weeks. Mice were made to perform swimming exercise with loads attached to their tails, corresponding to approximately 5% of their body weights, and the total swimming time until exhaustion was measured. Furthermore, the post-exercise concentration of serum urea nitrogen (SUN), pre-/post-exercise and post-rest concentration of lactic acid (LA), and pre-exercise hepatic glycogen were determined. Mice treated with CoQ10 showed a significantly prolonged exhaustive swim time (15 mg/kg/day; P < .05), increased liver glycogen contents (15 and 45 mg/kg/day; P < .01 and P < .05, respectively), and decreased SUN levels (1.5, 15, and 45 mg/kg/day; P < .01) compared to control animals. The LA level was not significantly changed. These results suggest that CoQ10 improves swimming endurance and has an antifatigue effect.

CoQ10 for Athletes

A recent study finds CoQ10 supplementation to improve aerobic capacity in trained and untrained individuals.

The study, published in Journal of the International Society of Sports Nutrition, recruited 41 male and female participants with varying degrees of athletic history; 22 participants had regularly participated in exercise, whilst 19 had not. The subjects were required to take 100mg CoQ10 or placebo morning and evening for 14 days, with blood and muscle tests taken on the first and last day. On the first and last day, the subjects also participated in three different tests designed to measure aerobic and anaerobic capacities.

Several markers reached significance; time to exhaustion on a treadmill improved following acute supplementation, whilst serum superoxide dismutase (SOD) decreased. Together, the increased muscle CoQ10 levels were able to be correlated with the increased time to exhaustion, as well as the reduced superoxide dismutase.

The authors posited two mechanisms behind the increased time to exhaustion. The increased muscle CoQ10 may have occurred alongside an increase in mitochondrial CoQ10, which would therefore have improved the functioning of the ‘oxidative phosphorylation’ enzyme chain( energy production), conferring improved oxygen usage. Alternatively, the decreased SOD may have implied an antioxidant action of CoQ10, and therefore improved protection of the muscle cell membrane.

Based on the Article

Cooke, M, Iosia, M, Buford, T, Shelmadine, B, Hudson, G, Kerksick, C, Rasmussed, C, Greenwood, M, Leutholtz, B, Willoughby, D, Kreider, R 2008, ‘Effects of acute and 14-day coenzyme Q10 supplementation on exercise performance in both trained and untrained individuals’, Journal of the International Society of Sports Nutrition, vol.5, art. no.8.

Chin J Physiol. 2009 Oct 31;52(5):316-24.

Attenuation of long-term Rhodiola rosea supplementation on exhaustive swimming-evoked oxidative stress in the rat.

Huang SC, Lee FT, Kuo TY, Yang JH, Chien CT.

Departments of Cardiology, Kuang-Tien General Hospital, Taichung, Republic of China.


Rhodiola rosea improves exercise endurance and fatigue. Treatment of 4 weeks of Rhodiola rosea extracts significantly inhibited swimming exercise-enhanced O2(-)* production in the blood, liver and skeletal muscle and plasma malonedialdehyde concentration. The expression in Mn-superoxide dismutase Cu/Zn-superoxide dismutase, and catalase in livers were all enhanced after 4 weeks of Rhodiola rosea supplementation especially at the dose of 125 mg/day/rat. Treatment of Rhodiola rosea extracts for 4 weeks significantly increased swimming performance. In conclusion, treatment of Rhodiola rosea extracts for 4 weeks could reduce swimming-enhanced oxidative stress possibly via the reactive oxygen species scavenging capability and the enhancement of the antioxidant defence mechanisms.

Planta Med. 2009 Feb;75(2):105-12. Epub 2008 Nov 18.

A randomised, double-blind, placebo-controlled, parallel-group study of the standardised extract shr-5 of the roots of Rhodiola rosea in the treatment of subjects with stress-related fatigue.

Olsson EM, von Schéele B, Panossian AG.

Department of Psychology, Uppsala University, Uppsala, Sweden. erik.olsson@psyk.uu.se

It is concluded that repeated administration of R. ROSEA extract SHR-5 exerts an anti-fatigue effect that increases mental performance, particularly the ability to concentrate, and decreases cortisol response to awakening stress in burnout patients with fatigue syndrome.


Withania is the Ayurvedic botanical medicine equivalent to the Chinese – Ginseng. In a study of 101 healthy 50 – 59 year old males given a supplement for one year, 71.4% of subjects reported improvement in sexual performance. Significant improvement was found in hemoglobin, red blood cell count, decreased cholesterol, hair strength increased and nail calcium was preserved implicating better bone calcium retention. Other studies have found marked cognitive ability increases, anti tumor, anti bacterial and anti-inflammatory activity. In debility, definite anabolic effects on par with ginseng have been observed. Mediherb 1996, Withania is obviously a very effective herb

Protective Effect of Korean Red Ginseng Extract on the Infections by H1N1 and H3N2 Influenza Viruses in Mice.

Yoo DG, Kim MC, Park MK, Song JM, Quan FS, Park KM, Cho YK, Kang SM.

1 Department of Microbiology and Immunology, Emory University School of Med. Atlanta, Georgia, USA .


Abstract Ginseng has been used in humans for thousands of years and is known to have multiple biological and immunomodulatory effects. Korean ginseng indicated an antiviral effect. In addition, ginseng extract exhibited inhibitory effects on the growth of influenza virus in vitro. This study provides evidence that intake of ginseng extract will have beneficial effects on preventing lethal infection with newly emerging influenza viruses.

Int J Ayurveda Res. 2010 Jul;1(3):144-9.

Effects of Withania somnifera (Ashwagandha) and Terminalia arjuna (Arjuna) on physical performance and cardiorespiratory endurance in healthy young adults.

Sandhu JS, Shah B, Shenoy S, Chauhan S, Lavekar GS, Padhi MM.

Department of Sports Medicine and Physiotherapy, Guru Nanak Dev University, Amritsar, Punjab – 143 005, India.


INTRODUCTION: Several medicinal plants have been described to be beneficial for cardiac ailments in Ayurveda like Ashwagandha(Withania) and Arjuna. Withania is categorised as Rasayanas, and described to promote health and longevity…

OBSERVATIONS: Our study showed that Withania somnifera increased velocity, power and VO2 max.

 CONCLUSION: Withania  may therefore be useful for generalized weakness and to improve speed and lower limb muscular strength and neuro-muscular co-ordination. Withania appears to be safe for young adults when given formentioned dosage and duration.

• Improved heart function and outcomes in congestive heart failure (334–900 mg/day)

• Fatigue and possibly cholesterol metabolism in fibromyalgia (100 mg/day)

• Semen parameters in male infertility (200 mg/day)

• Plasma CoQ10 levels and reduce muscle pain in statin users (preliminary results; 60 mg/day)

• Glycosylated haemoglobin in type 2 diabetics (200 mg/day)

• Physical performance in elite athletes, (300 mg/day)

• Symptoms of dry mouth, vitality and mood in the healthy elderly (100 mg/day)

• LDL-cholesterol levels in healthy volunteers (150 mg/day)

Ischaemic heart disease and cardiac surgery recovery

• Lipid profile (results mixed in those also taking statin drugs) and additional effects in atherosclerosis

• Reducing risk of cardiovascular disease and pre-eclampsia in pregnancy

• Reducing chromosomal damage in mitochondrial disease

• Physical performance in muscular dystrophy and chronic lung disease

• Reducing side effects of drugs, especially in cancer patients via inhibited peroxidation of lipoproteins present in the circulation (300 mg/day)

• Prevented migraine (150–300 mg/day)

• Improved symptoms of fibromyalgia (300 mg/day), diabetic neuropathy (400 mg/day)

• Improved muscle strength in muscular dystrophy (90–540 mg/day)