Not all workouts are created equal!
There are different levels of intensity that you should be working at depending on your goals. If you go to the gym and you casually meander on the bike while reading a book then you are probably not getting what you want out of your time on the bike. Don't get me wrong, riding the bike at a snails pace is better than sitting on your butt on the couch watching TV. But if you have specific things you would like to accomplish with your health and fitness then maybe you should take a look at what level you're currently working at and what level you should hit for your goals. There are five "zones" to help you gauge how hard you're working out.
What zone should you be working in? Decide what intensity you are going for. If you are just getting started you may want to start with zone 1 and build from there.
Zone 1- Healthy Heart Zone (Warm up) 50 - 60% of maximum heart rate: This is a great zone for people who are new to cardio or starting a new fitness routine. It is also a good zone for warming up for intense walks or hikes. In this zone you can decrease blood pressure, body fat, and cholesterol. It also has a low risk of injury. 85% of calories burned in this zone are fats! In this zone you should be able to sing a song easily while you work; meaning you are not close to winded. The only down side with this zone is that it takes a long time to get a good workout since it is a slow pace, but it gets your body started.
Zone 2- Fitness Zone (Fat Burning) 60 - 70% of maximum heart rate: This zone provides the same benefits as the healthy heart zone, but is more intense and burns more total calories. The percent of fat calories is still 85%. While in this zone you should be able to talk comfortably.
Zone 3- Aerobic Zone (Endurance Training) 70 - 80% of maximum heart rate: This zone will help improve your cardiovascular and respiratory system and can increase the size and strength of your heart. This is the preferred zone if you are training for an endurance event. More calories are burned than zones 1 and 2, with 50% of them coming from fat stores. In this zone it is harder to maintain a conversation. You can say a few words but then have to catch your breath.
Zone 4- Anaerobic Zone (Performance Training) 80 - 90% of maximum heart rate: in this zone you can improve VO2 maximum (the highest amount of oxygen one can consume during exercise) and therefore improve your cardio respiratory system. You also build your lactate tolerance which means your endurance will improve and you'll be able to fight fatigue better. This is a high intensity zone burning tons of calories; but only 15% from fat. In this zone you will be gasping for air. You may be able to say a word here or there, but will mostly be focused on your workout and breathing.
Zone 5- Red Line (Maximum Effort) 90 - 100% of maximum heart rate: This zone burns the highest number of calories, but very little of it is coming from fat. It is very intense. Most people can only stay in this zone for short periods. You should only train in this zone if you are in very good shape. It is very hard to maintain, because it involves exercises like intense sprints. Zone 5 can be painful and is where hardcore athletes train. Extreme care is a must: generally a doctor should clear you for this intense workout. Injury risk is elevated due to the intensity.
Keep in mind that you could stay in a specific zone but require progressively more aggressive workouts as your fitness levels rise. If you started jogging at a zone 3 pace then you may be jogging 12 minute miles at first. But, after doing that for a few weeks you may naturally pick up the pace, to an 11 minute mile, to get the same feeling and stay in zone 3. It is all relative to your specific fitness level. A walk for one person could feel like a zone 3, whereas another person may be jogging and feel like they are only in a zone 2. Do what is right for you and do not use someone else's measurements.
The body burns calories differently depending on what type of intensity we are working at. The chart below is an example of a 130 lb woman.
|Calories Expended||Low Intensity
60-65% of MHR*
80-85% of MHR*
|Total Calories per Minute||4.86||6.86|
|Fat Calories per Minute||2.43||2.7|
|Calories per 30 Minutes||146||206|
|Fat Calories per 30 Minutes||73||82|
|% of Fat Calories Burned||50%||39.85%|
|*MHR: Maximum Heart Rate|
Depending on what your goals are, you can do your cardio accordingly. While we burn a higher percentage of body fat when we are going at a lower maximum heart rate (MHR), we burn more over all calories and fat calories with the more intense cardio. One of the things that people should look at also is that cardio is not just for burning fat it is also meant to get our cardiovascular system into good shape hence the name "cardio". Cardio helps with other issues as well. It is believed that in order to help combat insulin resistance that a steady state cardio of 30 minutes to an hour at 75-85% of our max can help increase insulin receptivity.