Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
Can I do intervals inside or outside, with or without exercise equipment?
Yes, intervals work both indoors and out. Your body won't know the difference between running sprints on a track or the treadmill, cycling on the road or on a stationary bike (spinning classes are great interval workouts), or working on an elliptical or any other exercise machine. You can do intervals with swimming, rowing, cross-country skiing, or any other sport you like. Intervals work as long as you get your heart rate pumping and follow the ratios.
How often should I do intervals?
Intervals are intense, and so I recommend only one or two sessions per week to start, with at least three days in between for recovery and growth. You can do more than one or two after six weeks of training.
Overtraining is a common mistake of the overly eager beginner, and can lead to
impaired health and performance.
What are the advantages of interval training?
There are several advantages.
Fitness and performance improves quickly with interval training, typically in just a few weeks. I've known athletes who reported an improvement in speed after just two interval workouts.
Recovery time improves with interval training. Recovery is critical for athletes in sports like tennis, basketball, soccer or hockey, where the sport demands continuous stops and starts, or an endurance bike ride or road race where you hit hills and need to catch up quickly at the top in order to keep your pace. You'd never perform well if you sprinted all-out or climbed a hill and then needed two minutes to recover (also known as sucking wind). It would never work.
Research confirms that interval training improves fitness similarly to traditional aerobic training in much less time.
In one study comparing interval training to traditional training, subjects increased their fitness and the activity of many of enzymes that contribute to using oxygen efficiently with two and a half hours of intervals over two weeks compared with 10 and a half hours of traditional endurance training over the same time period.
In another study comparing the two methods of training, subjects increased the use of stored glucose (glycogen) and fat by the same amount after five days a week of training for six weeks, but the interval subjects trained only one and a half hours per week compared with four and a half hours per week for the endurance subjects.
Some interval training schedules can be too rigorous. In a study of subjects who did interval training every day for two weeks, the oxygen capacity increased, but anaerobic capacity did not. The investigators suggested that this was due to overtraining and exhaustion from daily interval sessions.
To reduce the effects of overtraining, investigators had subjects perform six, two and half-minute interval sessions over a two-week period, with one to two days of rest in between sessions, to promote recovery. Interval sessions consisted of four to seven "all-out" 30-second sprints on a stationary bike with a total of four minutes of recovery. This training regimen increased fat burning and doubled endurance capacity with just 15 minutes of intense cycling over a two-week period!
Interval sessions are tough, and you must "dig down deep" to find the motivation to push yourself, but the payoff is big. Find a training partner if you need help pushing yourself. Commitment to a partner will get you out the door when you don't feel like it, and a little healthy competition never hurts to increase performance.