In the past, most recommendations for exercise have called for a certain number of hours dedicated to physical activity. For instance, published guidelines from the Health and Human Services Department in 2008 suggested 150 minutes of moderate exercise per week — the equivalent of five 30-minute walks. The guidelines added that 75 minutes of vigorous exercise a week, such as jogging, could be substituted.
By most estimates, however, at least 80 percent of Americans don’t meet the recommendations. With the time constraints in mind, many people have turned to shorter, more intense workouts called high-intensity interval training.
But which is better for you?
The argument for traditional cardio exercise
By "traditional cardio exercise," scientists are usually referring to longer bouts of lower-intensity exercise. There are cases both for and against this type of workout. Here are some of the key research findings:
- Long, low intensity exercise improves insulin sensitivity and blood lipid levels more than high-intensity exercise. However, the calorie burn has to be comparable in each case to see these effects, according to research from Maastricht University in the Netherlands.
- Is there a lower-intensity exercise that involves nothing more than standing in one place? According to research from Chester University in England, standing at your desk puts you in a position to be more likely to lose weight. Standing for three hours a day burns about 144 calories – which is roughly equivalent to burning eight pounds of fat per year.
- Aerobic exercise – in the form of jogging, walking or swimming – is more effective for eliminating fat than weight training. Research from Duke University indicates that aerobic training or a program of aerobic and resistance training are both better at burning fat than resistance training alone. In fact, resistance training did not reduce fat mass or body weight significantly, regardless of differences in resting metabolic weight.
- In a new study from Queen's University in Ontario, Canada, doing 150 minutes of exercise was found to be as good for you if done all at once as it would be if broken up into several sessions. It didn't matter if people did 150 minutes once a week or 30 minutes of exercise five times a week, for example. In the end, it was all about the total amount, not the frequency.
The argument for high-intensity interval training
The new hot trend in exercise is high-intensity interval training, in which short bouts of hard exercise are combined with periods of rest to create a much shorter, more focused workout. This may be better suited for the modern adult who may have limited time to get in his or her exercise. But is it any healthier than training for a longer duration?
- In a study from the Norwegian University of Science and Technology, four minutes of exercise may be all you need. This short period of exercise was all people needed, according to the study, to develop endurance and health gains. However, the four-minute workout is deceiving, as it's actually 16 minutes – a one-minute interval performed at 90 percent maximum heart rate followed by a three minute rest, repeated four times. The researchers saw metabolic and cardiovascular health improvements, plus better blood sugar control and blood pressure profiles in those who used this style of exercise.
- The New York Times recently published a workout that generated significant buzz, indicating that seven minutes a day may be all you need. Scientists from McMaster University in Hamilton, Ontario found a way to work out the major muscle groups for as short a period as possible, but with maximum results. The workout involves 30 seconds of each move performed at a level 8 on the one to 10 "discomfort" scale. This exercise program includes jumping jacks, wall sits, push-ups, crunches, step-ups, squats, triceps dips, planks, running in place, lunges, T-push-ups and side planks.
- A study from the University of Copenhagen found that working out longer doesn't necessarily show any greater health benefits than for a shorter period. Working out 30 minutes a day is just as good as 60 minutes, the study found. Among slightly overweight (but otherwise healthy) young men, those who exercise for 30 minutes daily lost a similar amount of weight and body fat as those who did 60 minutes of daily exercise.
- Along similar lines of the short workouts, research from the University of Colorado and Colorado State University found that people can burn as much as 200 calories in two and a half minutes using high-intensity interval training. The study found that performing sprint exercises on a stationary bike was as effective as longer bouts of lower intensity exercise. The study authors feel that such short time commitments could be a good way to keep people motivated to stick with a workout regime.
- While it may not necessarily be an endorsement of high-intensity interval training, research from Saint Luke's Mid America Heart Institute found that marathon-type training is more likely to harm the heart. People should instead shoot for between 30 and 50 minutes of exercise per day, according to the researchers.
- Short bursts of moderate exercise can enhance memory, a study from the University of California Irvine found. While most research on the subject focuses on the effect of long-term exercise programs on cognitive function, this study found that memories are consolidated immediately following brief exercise in both healthy adults over 50 and adults over 50 with moderate cognitive impairment. This effect is believed to be tied to the exercise-induced release of norepinephrine, which is vital to memory modulation.
Published On: July 12, 2013