According to the American College of Sports Medicine, the ideal amount of cardio exercise to lose weight you need to complete is 200 to 300 minutes per week. This exercise needs to performed at between 55% and 70% of your maximum heart rate in order to burn the maximum amount of fat for your effort.
That may seem quite a lot, but it’s really only 3 to 5 hours a week, of medium intensity exercise.
What’s Your Optimum Heart Rate When Doing Exercise For Weight Loss
Your maximum heart rate is defined as 220 minus your age. So if your thirty years old, your maximum heart rate would be 190 beats per minute.
So to exercise at 55% to 70% intensity, your heart rate should stay in the range of between 55% and 70% of 190 – which is 104 to 133. Keeping your heart rate in this range whilst exercising while mean you’re burning the optimum amount of fat.
You are not expected to engage in five hours of cardiovascular activity at 70% of your maximum heart rate immediately. Start slow and build up gradually. For example, if you were previously sedentary, you can start with brisk walking at an exercise heart rate of 55% of your maximum heart rate three days a week, 20 minutes each time, and work upwards from there.
Progress by keeping the exercise intensity low and increasing the exercise duration or distance by about 10% per week. Once you have reached the desired frequency and exercise duration, start increasing the intensity. For example, if you were previously brisk walking, you can step up the intensity by alternating between 10 minutes of brisk walking and 5 minutes of jogging. Once you are accustomed to that, you can alternate between 10 minutes of brisk walking and 10 minutes of jogging, and so on.
Timing of Exercise
Does it matter what time during the day you exercise? Early in the morning, when the air is cool and clean, is ideal, especially if you exercise outdoors. But the overriding factor is convenience. We would be happy to find time to exercise, let alone be picky about the time of day. If you have a regular lunchtime, you may find it convenient to exercise then.
Some people prefer to exercise after work to unwind. Some finish work late or at a different time every day, so they may prefer exercising early in the morning, when the time is their own. Most people have difficulty falling asleep within two hours after exercise (due to elevated adrenaline levels), so exercising close to bedtime may not be ideal. The bottom line is: Choose a time that best fits your schedule, so that you maximize your total exercise time.
Another consideration is mealtimes. If you exercise on an empty stomach, you may feel too lethargic to exercise at the desired intensity and duration. But if you exercise soon after a meal, you would find it hard to exert yourself on a fall stomach. Generally, the most comfortable time to exercise is about two hours after a main meal.
Comfort aside, does the timing affect fat-burning? For example, if we exercise on an empty stomach, do we burn more body fat?
Our bodies have two main energy stores: the carbohydrate store (in the form of glycogen in the liver and muscles) and the fat store.
At moderate exercise intensities, the preferred fuel is carbohydrate, and when that runs out, the body will have no choice but to depend almost solely on the fat store. The body has about 2,000 kcal of carbohydrate stored up. When that is about to be used up, we feel like we’ve “hit the wall”, as the body starts to rely heavily on the fat store, which releases energy slowly. This is why it is hard to maintain a high exercise intensity after hitting the wall.
It usually takes about 90 to 120 minutes of moderate- to high-intensity exercise (i.e. at 70% to 75°/o of the maximal aerobic capacity) before hitting the wall. However, when we are in a chronic energy deficit, our carbohydrate store is already “half empty”, so we tend to hit the wall earlier. Aiming to hit the wall during routine exercise is not wise, as it is not sustainable and the total energy expenditure is not optimal over a long period.
Appetite is suppressed during and immediately after exercise, especially moderate-to high-intensity exercise. Take advantage of that. For example, if you tend to have a voracious appetite during dinner, go for a good workout just before dinner. That way, you won’t eat as much for dinner. However, bear in mind that, an hour after exercise, your appetite will not only return but also increase, so going for supper more than an hour after a workout is not a good idea.