When you are exercising the intensity of exercise correlates with how you feel, how you breathe, how fast your heart rate is.
Light exercise intensity
You are not noticing any changes in breathing.
You are not sweating unless it is a hot, humid day.
Maximum heart rate is 40-50% of MHR.
Moderate exercise intensity
Moderate activity feels somewhat hard. Here are clues that your exercise intensity is at a moderate level:
Your breathing becomes deeper and more frequent, but you're not out of breath.
You might develop a light sweat after 10 minutes.
You can carry on a conversation, but you can't sing.
Maximum heart rate is 55-69% of MHR
Vigorous exercise intensity
Vigorous activity feels challenging. Here are clues that your exercise intensity is at a vigorous level:
Your breathing is deep and rapid.
You develop a sweat after a 3-5 minutes of activity.
You can only talk in short phrases without pausing for breath.
Maximum heart rate is 70-85%
Beware of pushing yourself too hard . If you're short of breath, in pain or can't work out as long as you'd planned, feel exhausted after you finished, or not able to repeat the same intensity exercise the next day your exercise intensity is probably higher than your fitness level allows. Back off by 50 % of the time or intensity and advance gradually.
What is your Maximum Heart Rate (MHR)
Maximum heart rate — the upper limit of what your cardiovascular system can handle during physical activity.
The basic way to calculate your maximum heart rate is to subtract your age from 220.
For example, if you're 45 years old, subtract 45 from 220 to get a maximum heart rate of 175. This is the maximum number of times your heart should beat per minute while you're exercising.
Once you know your maximum heart rate, you can calculate your desired target heart rate zone — the level at which your heart is being exercised and conditioned but not overworked.
Here's how heart rate matches up with exercise intensity levels:
If you're not fit or you're just beginning an exercise program, aim for the lower end of your target zone (50 percent). Then, gradually build up the intensity. If you're healthy and want a vigorous intensity, opt for the higher end of the zone.
How to determine your target zone
To determine your desired target heart rate zone, use an online calculator. Or, here's a simple way to do the math yourself. If you're aiming for a target heart rate of 70 to 85 percent, which is in the vigorous range, you would calculate it like this:
Subtract your age from 220 to get your maximum heart rate.
Multiple that number by 0.7 (70 percent) to determine the lower end of your target heart rate zone.
Multiply your maximum heart rate by 0.85 (85 percent) to determine the upper end of your target heart rate zone.
For example, say your age is 45 and you want to figure out your target heart rate zone for vigorous intensity exercise. Subtract 45 from 220 to get 175 — this is your maximum heart rate. To get the lower end of your target zone, multiply 175 by 0.7 to get 123. To get the higher end, multiply 175 by 0.85 to get 149. So your target heart rate zone for vigorous exercise intensity is 123 to 149 beats per minute.
How to tell if you're in the zone
So how do you know if you're in your target heart rate zone? Use these steps to check your heart rate during exercise:
Take your pulse for 15 seconds. To check your pulse over your carotid artery, place your index and third fingers on your neck to the side of your windpipe. To check your pulse at your wrist, place two fingers between the bone and the tendon over your radial artery — which is located on the thumb side of your wrist.
Multiply this number by 4 to calculate your beats per minute.
Here's an example: You stop exercising and take your pulse for 15 seconds, getting 33 beats. Multiply 33 by 4, to get 132. If you're 45 years old, this puts you in the middle of your target heart rate zone for vigorous exercise, since that zone is 123 to 149 beats per minute. If you're under or over your target heart rate zone, adjust your exercise intensity.
Target heart rate tips
It's important to note that maximum heart rate is just a guide. You may have a higher or lower maximum heart rate, sometimes by as much as 15 to 20 beats per minute. If you want a more definitive range, consider discussing your target heart rate zone with your physician