Heart Rate For Interval Training

Heart rate measures how intensely you are performing an exercise routine. According to the American College of Sports Medicine, aerobic fitness improves when working in a range of 55 percent to 80 percent of maximum heart rate. The less fit you are, the harder it is to sustain the higher points in this zone. Interval training, which involves bouts of higher intensity exercise with periods of lower intensity or rest time, permits you to work harder than you might be able to sustain with continuous training. Monitoring your heart rate can help you be more precise in your interval training and achieve better results, regardless of your goal.

Significance

Interval training helps with weight loss, improves overall fitness level and enhances athletic performance. Although you can work intervals by simply evaluating your perceived exertion, heart rate monitoring provides you with a more exacting determination of your work zones. With heart rate monitoring, you can be assured that you are working hard enough to experience results and are truly experiencing a "rest" during the off intervals.

Types

Aerobic intervals involve working between a low aerobic zone (55 percent to 65 percent of maximum) and a high zone (75 percent to 80 percent of maximum). Anaerobic intervals call for a work period falling within 80 percent to 95 percent of maximum heart rate, while the rest periods may drop to an aerobic zone or even lower (below 50 percent of maximum). Anaerobic intervals are very short in nature and usually involve longer rests. The American Council on Exercise notes that anaerobic work is hard to maintain for any period of time because when you work near your maximum heart rate, the body seeks energy exclusively from muscle glycogen rather than from a combination of fuels.

Function

The type of intervals you perform depends on your particular goals. If you seek to improve cardiovascular endurance--like moving from being a walker to a runner--aerobic intervals suffice. Aerobic intervals are also appropriate for endurance athletes like distance runners or century cyclists because they help your body adapt to working at a higher heart rate zone (up to 80 percent of maximum) for longer, improving race times and overall performance. Anaerobic intervals help improve sprinting and power for sports like tennis or football. A New Zealand study published in the "Scandanavian Journal of Medicine and Science in Sports" in 2009 showed that, among well-trained athletes, adding just two 30-second anaerobic intervals to an endurance workout where heart rate was at 60 percent to 70 percent of maximum resulted in "worthwhile" gains in overall sprint performance.

Expert Insight

Interval training shows a slight superiority over steady state heart rate training in increasing the rate of fat loss. A study in the journal "Research in Sports Medicine" by experts at The University of Western Australia compared the effects of diet education alone, or diet education coupled with either endurance style exercise or interval style exercise. They found that, although both types of exercise enhanced conditioning, the interval group lost more fat than the steady state exercise group or those receiving dietary counseling alone.

As reported in a study from the February edition of the journal "Metabolism," sprint interval training--defined as four to six 30-second maximum sprints (anaerobic) followed by four and a half minutes of recovery--improved several metabolic and vascular health risk factors in 36 overweight, de-conditioned men. This suggests that interval training provides a potential treatment for the condition known as metabolic syndrome--a cluster of risk factors that increase a person's chances of developing chronic diseases like type 2 diabetes and heart disease.

Considerations

Although interval training is a valuable training tool, it should be used in moderation. Intervals, especially high-intensity ones that dip into your anaerobic zone, provide the most benefit when performed only one or two times per week, or you risk overtraining. Steady-state cardio training, at a zone of about 60 percent to 80 percent of maximum, still offers benefits for overall health and weight management.