1. Its boring! Who really wants to spend half an hour or more running, cycling, rowing, etc .
2. Your body will adapt to it! As you get fitter, it becomes harder to burn the same amount of calories as when you started exercising because your body adapts and becomes more efficient. So what do you do to burn the same amount of calories as you used to? Well if you continue with aerobic training the answer is either go for longer or do the same time quicker neither of which are particularly enjoyable.
3. The fat burning zone or heart rate training doesn't work. Yes, you burn a higher percentage of fat at a sub-maximal intensity but the overall calories burnt are less than a higher intensity workout. (See the post below for more on Fat burning zone and heart rate training for fat).
4. Sprinters have less fat than marathon runner.
5. Yes, you burn calories whilst doing aerobic training however it may be detrimental to your muscle growth. As I've said many times before, the more toned you are the more calories you burn whilst sitting at home. Aerobic training is largely catabolic (breaking down), which can consequently reduce the development of muscle growth. Less muscle = lower calorie expenditure = lower fat loss.
The answer? interval training
Interval training is not aerobic exercise! Before I tell you what interval training is let me tell you what aerobic training is. Aerobic training (with oxygen) is exercise at a low or moderate intensity that can be maintained for a relatively large amount of time as long as oxygen is available for the muscles.
Ok, so now let me tell you about interval training. This form of training is known as anaerobic training (little or no oxygen available). The key benefits of this training method are that it not only burns calories whilst you are doing it, it also burns more calories when you have finished as it revs up your metabolism for up to several hours afterwards, therefore helping you burn more calories through the day.
So what exactly do I do when interval training?
First off, choose an activity, running, rowing, etc . However , I recommend you do not do the same exercise every time. Remember your body will adapt! Try changing the machine or the activity every 2 sessions to avoid this.
Once you have warmed up (5 mins) increase the intensity for 1 minute. This should be full out effort or as close to as possible (not recommended for those with heart problems). Think of a scale between 1-10, 10 being the most difficult, 9-10 is where you should be at this point. Once you have completed that slow down to a comfortable (5-6 out of 10) that you can maintain for 2 minutes. This is one bout, you should repeat this between 3-6 times depending on your level of fitness followed by 3 minute cool down. The total work out should be between 17-26 mins depending on how many bouts you do carry out.