The Marathon Myth: High intensity Interval Training (H.I.I.T.) vs. Long Duration Training (L.D.T.)
I have written several FitBit Articles this year detailing the efficacy of High Intensity Interval Training (H.I.I.T. training). H.I.I.T. has been shown to develop much higher levels of cardiovascular fitness in much shorter periods of time than the traditional L.D.T. Not only have numerous Universities reported on research conducted by some of the top Cardiologists and Exercise Physiologists in the country, but we also have world-champion endurance athletes using H.I.I.T. to smash all existing race records.
Recent research now demonstrates that retention rates for H.I.I.T. are significantly higher than L.D.T. Previous research had shown that as intensity increased, retention decreased. This research did not take into consideration that H.I.I.T. by its very nature, requires much shorter durations.
For fitness training, H.I.I.T. duration is typically 15-20 minutes, while typical L.D.T. training is 60-90 minutes. H.I.I.T. Frequency is typically 2-3 days/week, while L.D.T. Frequency is 6-7 days/week. This significant decrease in both duration (Time) and Frequency (number of training sessions/week) appears to be the primary reason for increased retention rates and exercise adherence.
The one big question in all personal trainer minds should be "Great, but what about SAFETY?" Remember rule #1 for all IFPA Certified Personal Trainers, Medical Fitness Specialists or any one of our other Certified Professionals that are certified in one or more of the over 70 other IFPA certifications is DO NO HARM!
This is probably the most significant and controversial of all the news research coming out on H.I.I.T. vs. L.D.T.: H.I.I.T. is actually safer than L.D.T! Read it again! H.I.I.T. has shown to be safer than L.D.T.!
This is contrary to many current beliefs and is contrary to what has been considered "Common Sense" high intensity MUST be a higher risk than low-moderate intensity, long duration training, but once again, "Common Sense" and long held beliefs have been proven WRONG.
At risk of sounding like the mean old grinch that stole Christmas from all the hard core marathon runners and endurance athletes, I am required to report to you conclusive research that demonstrates that H.I.I.T. is actually safer than L.D.T.
According to Dr. Eric Larose, exercise and cardio health expert from the University of Loval in Quebec City, "Exercise reduces cardiovascular risk by a factor of three, but vigorous exercise such as marathon running increases cardiac risk by a factor of seven."
Dr. Larose's study shows marathon runners suffer temporary heart damage because of the level of exertion when running such a long distance. The further you run the more stress you place on your body.
According to Dr. Arthur Siege, Director of Internal Medicine at Harvard's McLean Hospital in Belmont, Massachusetts, "Your Body doesn't know whether you've run a marathon or been hit by a truck." I used to run the Boston Marathon. When running a marathon your body kicks into Survival Mode. That releases a chemical cascade inside you. Your adrenal glands release stress hormones like cortisol and vasopressin. Your muscles release a protein called cytokines and that makes your liver produce C-reactive protein. This triggers an inflammatory response to protect you from all the havoc raging in your body. This can lead to cardiac arrest which is not uncommon in such long races. As you go deeper into the 26.2 mile race, your muscles take on the brunt of the stress and that includes your heart.
Dr. Siege and colleagues conducted a study in the American Journal, of cardiology. They analyzed the blood of marathon runners less than 24 hours post race. The runners showed high levels of inflammation and coagulation markers associated with heart attacks.
Even more disturbing is another study in the American Heart Association Journal: Circulation that found abnormalities in how the blood was pumped into the heart after running a marathon, including some runners that had difficulty refilling the chambers of their hearts.
There is a lot of research and studies being conducted on both H.I.I.T. and L.D.T. and I will be reporting on this further. Some very passionate marathoners are offering numerous explanations for the deaths associated with L.D.T. including: (1) undiagnosed congenital heart defects, (2) Electrolyte imbalances, (3) too little or too much hydration, (4) heart exhaustion in high heat/high humidity situations, (5) statistically low death rates and more.
Regardless of defending opinion in the face of these facts, there is a relatively simple solution to the problem, try H.I.I.T. Protocols following all the Exercise Science Principles you learned in the IFPA Personal Fitness Trainer or the Group Fitness Instructor Certification Courses.