Target heart rate (THR), or training heart rate, is a desired range of heart rate reached during aerobic exercise which enables one's heart and lungs to receive the most benefit from a workout. This theoretical range varies based on one's physical condition, age, and previous training. Below are two ways to calculate one's Target Heart Rate. In each of these methods, there is an element called "intensity" which is expressed as a percentage. THR can be calculated by using a range of 50%–85% intensity.

(Warm up) — 50–60% of maximum heart rate: The easiest zone and probably the best zone for people just starting a fitness program. It can also be used as a warm up for more serious walkers. This zone has been shown to help decrease body fat, blood pressure and cholesterol. It also decreases the risk of degenerative diseases and has a low risk of injury. Fats are 85% of food energy burned in this zone.

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 food energy. The percent of food energy from fat is still 85%.

Aerobic Zone (Endurance Training) — 70–80% of maximum heart rate: The aerobic zone will improve your cardiovascular and respiratory system and increase the size and strength of your heart. This is the preferred zone if you are training for an endurance event. More food energy is burned with 50% from fat.

Anaerobic Zone (Performance Training) — 80–90% of maximum heart rate: Benefits of this zone include an improved maximum (the highest amount of oxygen one can consume during exercise) and thus an improved cardio-respiratory system, and a higher lactate tolerance ability which means your endurance will improve and you'll be able to fight fatigue better. This is a high intensity zone burning more food energy, 15% from fat.

Red Line (Maximum Effort) — 90–100% of maximum heart rate: Although this zone burns the highest amount of food energy, it is very intense. Most people can only stay in this zone for short periods. You should only train in this zone if you have a very high fitness level and have been cleared by a physician to do so.

The Karvonen method factors in Resting Heart Rate (HRrest) to calculate Target Heart Rate (THR):
THR = ((HRmax – HRrest) × %Intensity) + HRrest
Example for someone with a HRmax of 180 and a HRrest of 70: 50% intensity: ((180 − 70) × 0.50) + 70 = 125 bpm85% intensity: ((180 − 70) × 0.85) + 70 = 163 bpm

Find your target heart and find what works for you.