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Proven Benefits of Short, High Intensity Runs, Walks, Workouts

Over the last few years there has been a change of emphasis on training routines from long duration low intensity sessions to shorter high intensity sessions. It appears that short is really better for a variety of reasons. Those hours and hours spent on long runs and walks may be less effective for fitness and weight loss.

This new trend appears to be a flow on from the proven success of interval training for long events. Short session and interval training involves a set of high-intensity exercise workouts, with intervening rest or low intensity periods.

It is also related to hill training techniques and high work rate exercises. Knowing your 'magic pace' is also part of this. Breaking through training plateaus is also a key for improvement.

You may be wasting your time and energy on all those hours you spend running or walking each day when you can get more benefits from short more intense sessions. Boredom, lack of variety and over training can ruin a good training program and weight loss strategy.

On the other hand, intense training may have higher risks of injury and some people like their time spent training over long periods of time.

This article reviews some of the recent advice and research studies that review short session workouts, runs, walks, swims and other exercising and their pros and cons.

Burning fat - Level of Intensity and Duration is Best

What forms of exercise (interval vs continuous; low-intensity vs high-intensity) burn the maximum amount of fat? Recent studies that examined subjects training under different durations found that shorter higher intensity sessions burnt more fat. When a single, 60-minute session of exercise was divided onto two, 30-minute long session with 20 minutes of rest in between more of the energy expenditure was derived from fat. Also repeated higher intensity exercise sessions appeared to change the whole body and muscle metabolism to make it more efficient in using both fat and carbohydrate. The researchers recommended breaking up your exercise sessions in to shorter bouts and introducing more variety. This does not necessarily mean eliminating all longer session, but to include weekly bouts of short duration high intensity workouts. Introducing variations in the type of exercise is also a good idea.

The image below shows that the relationship between oxygen consumption and energy expenditure for walking is not linear but increases rapidly at higher speeds.

Increasing the intensity increases that rate at which oxygen is consumed and energy expended | Source

The table below shows how the calories burnt for various types of exercise varies with intensity. It also shows the total equivalent amount of fat in onces and grams for 90 minutes of the various exercises. For most types of exercises, the calories burnt during 30 minutes of intense activity was equivalent to that consumed by 60 minutes at the lowest intensity rate.

Calories Burnt by Various Exercise Types and Intensities

ExerciseIntensityCalories for 30 minutesCalories for 60 minutesCalories for 90 minutesEquivalent Ounces of fat for 90 minutesEquivalent grams of fat for 90 minutes
Aerobics Light 120 240 720 3.3 93.3
Moderate 200 400 1200 5.5 155.5
Vigorous 300 600 1800 8.2 233.3
Walking 4 km/hr 105 210 630 2.9 81.6
7 km/hr 200 400 1200 5.5 155.5
10 km/hr 370 740 2220 10.1 287.7
Running 9 km/hr 320 640 1920 8.8 248.8
10 km/hr 350 700 2100 9.6 272.2
12 km/hr 430 860 2580 11.8 334.4
16 km/hr 550 1100 3300 15.1 427.7
Cycling 9 km/hr 120 240 720 3.3 93.3
16 km/hr 220 440 1320 6.0 171.1
21 km/hr 320 640 1920 8.8 248.8
Swimming 25 metres/min 165 330 990 4.5 128.3
40 metres/min 240 480 1440 6.6 186.6
50 metres/min 345 690 2070 9.5 268.3
Rowing Light 200 400 1200 5.5 155.5
Vigorous 420 840 2520 11.5 326.6

Everything in Moderation

Various studies have shown that the cardiovascular benefits of vigorous aerobic exercise training appear to peak at about 30-60 minutes daily. Beyond that the benefits of the extra exertion diminish and may even cause adverse effects in some people.

A Danish study found that a group of overweight young men lost more weight exercising moderately for 30 minutes several times a week over a 13 week period than another group that exercised for 60 minute sessions. It appeared that the group of subjects who had longer exercise sessions ate more than the moderate exercisers and were less active generally during the other parts of the day. Motion sensors worn by all of the subjects confirmed these patterns.

The group of men who had 30 minute sessions were more invigorated by their exercise. They were more active during the day and less inhibited by feeling fatigued. The moderate exercise plus all the little bursts of activity, and less food consumption, all added up to help them lose more weight.

Benefits of Short Intense Workouts - The Pros

Time - This is an obvious benefit for people who claim they don't have enough time for exercising. It is much easier to set aside 30 minutes every other day than 60 minutes

Better Return for Effort - If you are going to put your time, sweat and money into equipment and gym costs, you want to have a reasonable expectation that your efforts will pay a dividend in terms of fitness and weight loss. Short intense workouts are likely to provide a better return than slow, lower intensity exercises. It's sad that very slow long walks may achieve virtually nothing in term of fitness because you never get the heart rate up high enough. It will burn calories, but at perhaps half or a quarter the rate of faster walking.

Interest and Avoidance of Boredom - Exercising and working out should be fun and play, not uninspiring drudgery. This is why cross-training and variety are so important. Challenging and vigorous activity is more interesting than a slow 90 minute jog or an hour ob the treadmill.

Performance - Short intense training builds aerobic fitness in a similar way to interval training. The fitter you are the better will be your performance - your times and work capacity. Short, intense exercise sets the foundation for being able to dominate in your sport.

Less Demanding Space and Organisation - If you are committed to a sixty minute jog or bike ride there are limited places where you can so it. Short interval training is much more flexible especially using cross training and variety.

Consistency as You age - As people get older they lose the capacity to work hard for long periods of time. It is easier to maintain a short intense and flexible training strategy over a long period of time as people get older.

Short Intense Workouts - The Cons

Clearly the benefits of short intense workouts mostly apply to relatively fit you people.

Sedentary and older people need to ease into it to avoid injuries.

For older people there are individual risks that inappropriately high-intensity exercise my induce a heart attack.

The trick is to be sensible about it and to vary the intensity and allow a lot of warm-up and warm-down period before and after the training session.

The extreme high-intensity training should not be undertaken until people have at least three months of normal training to get fit and flexible.

The best approach is to gradually increase the duration and intensity of the session or to add more interval sessions as you go.

Some people like the meditation and mental benefits of a long run out in the country side, Short intense activity does not provide these benefits.

In this case it is probably better to stick with what you like.

Perhaps you could add some more vigorous parts into these routines or use routes up hills.





Lifting the intensity of your exercise boosts the benefits of training
Lifting the intensity of your exercise boosts the benefits of training, Source: https://commons.wikimedia.org/wiki/File%3ADive_off!.jpg
Interval training has proven benefits. But increasing the intensity of runs and walks is better for your heart and circulation
Interval training has proven benefits. But increasing the intensity of runs and walks is better for your heart and circulation Source: Public Domain
Shifting from low intensity walks and strolls enhances the benefits of the exercise
Shifting from low intensity walks and strolls enhances the benefits of the exercise Source: Public Domain