These days virtually everyone is stressed for time and many people struggle to find time to work regular exercise into their busy lives. If you typically use lack-of-time as your excuse for not exercising, the study I’m reporting on today annihilates your excuse(s).
Over the past decade, numerous studies have touted the benefits of high intensity interval training: greater benefits in less time. However, many of these studies have had some shortcomings (usually due to funding limitations) such as short duration, lack of control group, or only measuring a few fitness benefits. Consequently, some people have still questioned whether or not short bursts of high intensity exercise are superior to traditional endurance training.
Recently Martin Gibala, Ph.D. and his colleagues at McMaster University in Canada organized and conducted an extremely well designed study that compared the benefits of very short, very intense workouts with traditional moderately intense endurance workouts such as long runs or bike rides.
THE OUTCOME: Benefits From 1-Minute of Intense Exercise Equals 45-Minutes Of Moderate Exercise. Expressed another way, during the 12-week trial, the high-intensity interval cyclists rode their bikes for a total of 6 hours with only 36 minutes at high intensity compared to 27 hours of riding for the moderate intensity endurance cyclists.
STUDY DESIGN: 25 out-of-shape young men were recruited and randomly divided into three groups. The control group made no change in their non-exercising lifestyles. The second group began a traditional endurance-workout routine, which consisted of riding a stationary bicycle at a moderate pace in the exercise lab for 45 minutes, with a two-minute warm-up and three-minute cool down.
The third group engaged in interval training, using the shortest workout ever designed to document the benefits of short-duration high-intensity interval exercise. The high-intensity cyclists warmed up for two minutes on stationary bicycles, then pedaled as hard and fast as possible for 20 seconds, followed by a slow pace for two minutes. This cycle was repeated two more times; 20 seconds of all-out sprinting followed by 2 minutes of slow-riding recovery. At the end, they continued peddling slowly for a 3 minute cool-down. The entire workout lasted 10 minutes, with only one minute of that time being intense all-out exertion.
Both groups of exercising men completed three sessions each week for 12 weeks, which is a period of time that is about 2 times longer than most previous studies conducted on high-intensity interval training.
The scientists measured the men’s aerobic fitness as an indicator of baseline health as well as their body’s insulin sensitivity and their ability to regulate blood sugar levels. The researchers also took muscle biopsies to examine how well their muscles functioned at a cellular level.
At the conclusion of the 12-week trial, they re-tested the men’s aerobic fitness, their blood sugar control and muscle function. The results revealed that both groups of exercising men recorded virtually identical gains. Both groups gained about a 20% increase in endurance and had similar gains in insulin resistance and insulin control. Also, both groups recorded significant increases in the number and function of microscopic structures in their muscles that are related to energy production and oxygen utilization.
TAKE HOME: 3 months of both short-term high intensity exercise and moderate intensity endurance exercise produced virtually identical benefits in health and fitness. Hence, neither approach was superior. The major differences were TIME and INTENSITY: 36 minutes of high-intensity exercise (6-hours total with warm-ups & cool downs) compared to 27 hours of moderate-intensity endurance exercise.
The title of this study was: Twelve Weeks of Sprint Interval Training Improves Indices of Cardiometabolic Health Similar to Traditional Endurance Training despite a Five-Fold Lower Exercise Volume and Time Commitment. It was published in the journal PLoS One, April 26, 2016.
SUMMARY: I’m not personally advocating this 1-minute high-intensity exercise program. I just wanted to review this study to emphasize how people can save an enormous amount of time and obtain significant health benefits by engaging in high-intensity interval training. I think it is also important for people to realize that regularly riding or running at the same moderate level of intensity does not increase your ability to take in and utilize oxygen and it does increase your muscular strength.
High intensity interval training (HIIT) is critical if you want to improve your exercise performance and/or athletic ability. Simply put, you must push yourself close to your maximum capable level of physical exertion in order to make gains. Put another way, about 90% of the benefit(s) of exercise is gained during the top 10% of your physical exertion capability.
MY PERSONAL PROGRAM: I personally like the Sprint 8 program that was developed and popularized by Phil Campbell who is a certified personal trainer with the American College of Sports Medicine. Campbell created the Sprint 8 program to bring the science of high-intensity training to cardio workouts and he is the author of the popular book titled Ready, Set, Go! Synergy Fitness.
Sprint 8 requires 8 cycles consisting of 30 seconds all-out-intensity exertion followed by 90 seconds of moderate intensity exercise recovery. Dr. Mercola’s interview with Phil Campbell provides an excellent explanation and demonstration of Sprint 8.
Any type of aerobic exercise can be used for Sprint 8 such as fast-walking, jogging, running, cycling, swimming, etc. Since I have total knee replacements in both my knees, I prefer to do my Sprint 8 sessions on an elliptical trainer which allows me engage with low impact on my knees.
One of the great benefits of engaging in Sprint 8 is its documented ability to dramatically increase production of human growth hormone (HGH), which is a key to health and fitness. Phil Campbell emphasizes that an intense exercise program like Sprint 8 should not be done more that 2 or 3 times per week.
Why Sprinting Improves Endurance: The following information comes from an article published on Dr. Gabe Mirkin's Fitness and Health E-Zine titled Why Sprinting Improves Endurance (11/29/2009). Mirkin reported on research conducted by Jens Bangsbo at the University of Copenhagen. Bangsbo instructed competitive distance runners to REDUCE their weekly milage by 25%, and to also run 8 to 12 30-second maximum speed sprints 2 or 3 times per week for 6 to 9 weeks.
The sprint group made significant improvement in both their 3K (1.8 mile) and 10K (6 mile) race times and half of these athletes ran their BEST TIMES EVER, even though many had been racing for more than five years. By comparison, the control group of runners who continued their regular training program made no improvements.
Dr. Bangsbo's research explained why intense interval training improves athletic performance. When a muscles contract, potassium is pumped out of cells. Intense exercise strengthens the sodium/potassium pump in cell membranes which increases the speed of potassium re-entry into the cell. This speeds recovery rate and increases the strength capability of the muscles.
Train hard. It pays off......at any age. Dr. Gabe Mirkin’s complete report can be read at: http://www.drmirkin.com/public/ezine112909.html
Strength/Resistance Training: This article has been about high-intensity aerobic exercise. However, I want to emphasize that a well-rounded exercise program MUST also contain some strength/resistance exercise two to three times per week in order to maintain muscle mass.