If you are just looking to keep toned, keep up your stamina up or just burn some of your daily consumed calories, it really does not matter when you do your cardio workout. Later in the day probably better.
Now if you are trying to drop some weight, you will want to do your cardio workout first thing in the morning. You will not want to eat any thing before your workout.
Working out on an empty stomach forces your body to burn just body fat. It has no other fuel. You will want to keep your heart rate around 70% of your Max heart rate.
To figure this out just take 220 minis your age and take 70% of this figure. Lets say your age is 44 so you will take 220 – 44 = 176. This gives you your max heart rate for training. Now take it 176 x .7 = 123 beats per minute.
Your workout should last around 30 minutes. You are not trying to over do it. This pace will keep you from burning any muscle. This will work better with a diet of higher protein and lower carbs. This will keep your blood sugar in check.
Like all types of training, you will want to try this out and see how it works for you. Everyone is different, and different exercise times work better for different people. But stay within the guidelines and you will increase your fat lose.
