I often get asked about the “best way” to do lose fat through cardio exercise. This article will look at the two most prominent forms of cardio training: Steady State and Interval. Both have their pros and cons, which we will examine below.
Steady State:
This term refers to working at a steady pace, ultimately trying to maintain a heart rate within 65-85% of your age-determined maximum. The specific effects of this form of training are directly related to the intensity and duration:
|
Zone |
Intensity |
Duration |
Pro |
Con |
| Healthy Heart | 50-60Brisk walkWarm-up and cool-down zone | Long | Safe for cardiac rehab, overweight, and injury rehab patientsIncrease health by strengthening heart and reducing body fat, cholesterol, and blood pressure | Restricted caloric expenditureWill not increase endurance or strength in fit individuals |
| Temperate(Sometimes referred to as “fat-burning” zone)** | 60-70Light jog | Mid-long | Not very strenuousIncreasing rate of fat mobilization for use as primary fuel | Restricted caloric expenditureWill not increase endurance or strength in fit individualsRisk of repetitive stress related syndromes |
| Aerobic | 70-80Vigorous jogRunning | Mid | Increase fitness through enhanced vasculature (capillary density), lung capacity, VO2, heart size and strengthSimilar use of fat vs carb as fuel | Risk of overexertion in some populationsRisk of repetitive stress related syndromes |
| Anaerobic Threshold | 80-90Vigorous run | Short | Sport specific gains by training body to work without sufficient oxygenEnhance delayed onset of fatigue in oxygen deprived state | Risk of overexertion in some populationsRisk of injury |
| Red Line | 90-100All-out sprint | Very short | Enhances gains attained in anaerobic threshold zone | Further elevated risk of injury and overexertion |
| * HRMax = 220-Age** Fat-burning zone myth: the enzymes employed to mobilize fat require more time than those that mobilize carbs; therefore, it is only in the lower intensity zones that we see fat used as a primary fuel source (i.e. we allow sufficient time for these enzymes to get fatty acids into the energy system chain). Hence, up to 85% of the fuel used in this zone is from fat stores. This is misleading in that it takes the focus away from the importance of overall calorie burning (both before and after exercise) and places it solely on the primary fuel source. Bottom line: yes, when exercising for prolonged periods of time in the temperate zone you will be utilizing fat stores as a primary fuel source, BUT you will NOT be burning as many calories (before and after your workout) as you would when training in a more intense zone. | ||||
Adapted from: http://www.howtobefit.com/five-heart-rate-zones.htm and http://www.runningforfitness.org/calc/hrzones.php
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Interval:
There are numerous definitions for the widely used term; but for our purposes, we are referring to alternating between high and low training zones for the full duration of the training bout. Traditionally, choosing a high intensity pace and performing it for a short period of time, followed by a low intensity pace which is performed for slightly longer, with this process being repeated several times. Interval training has gained a lot of great publicity as of late, being regarded as the superior form of cardio training for both conditioning and fat-loss.
Let’s examine what makes this form of training so beneficial:
- Can yield benefits in shorter period of time (very applicable to today’s lifestyle trends)
- More enjoyable/break monotony of steady state training
- Burn more calories while exercising
- Train both aerobic and anaerobic systems
- Relativity to real life activities (short, intense bouts vs long, steady bouts; e.g. running up the stairs at King subway station)
- Very effective “plateau breaker” (get out of that fat-loss slump)
- Lots of variations available and adaptable to all fitness levels
And the most important point…
- Research shows enhanced metabolic activity during and following the training bout
- This means your calorie burning mechanism (metabolism) is fired up to a greater degree and for longer than it would be following steady state training…you are in a supercharged state!
- At the muscular level, you are disrupting the normal state of your muscle cells and require significant amounts of energy to restore these cells to their normal, resting state; not seen to the same extent when dealing with steady state cardio bouts
Important guidelines:
- Always remember to spend 5+min at the beginning and end of your cardio bout to gradually warm-up and cool-down
- Must vary program every 3-4 weeks to avoid plateau
- Trail and error used to gauge initial pace settings (does it feel ok?)
- General high to low intensity time split ratio for beginner is 2min:1min, respectively
- Low intensity phase should be a comfortable pace for you; high intensity phase should be slightly harder than what you are accustomed to doing (find a pace that allows to work at a challenging pace just under your fatigue threshold)
- The low intensity phase should not be too intense as this is the recovery component
- Frequency of training remains the same at 2-3 times/week
- Form of exercise can vary; use treadmill, elliptical, bike, rower, etc
- Real importance lies in intensity and variation
- Focus less on calorie counting (calorie counting mechanisms on cardio equipment have many limitations and can be very misleading)
- Just focus on intensity for the set duration
- This form of training can be implemented into weight training programs
Sample interval programs:
Pre-set on cardio equipment:
- Interval
- Hill
- Speed Interval
- Random (not always as effective)
Manual:
- Beginner on treadmill: 3.0mph for 120sec (walk); 3.6mph for 60sec (brisk walk and/or incline); repeated 4-6 times
- Intermediate on treadmill: 5.5mph for 60-90sec (mild jog); 7.5mph for 30-60sec (run and/or inline); repeated 12-14 times
- Advanced on treadmill: 6.0mph for 60-90sec (run); 9.0mph for 30-60sec (sprint and/or inline); repeated 15-20 times
In conclusion, when it comes to fat-loss, interval training is the way to go. So mix things up a bit with some shorter duration, more intense bouts of cardio comprised of one (or more) of the many forms of interval training available to you.
Happy training!
