By Aaron Swanson, DPT
This February many of you will be spending your time wondering which Valentine’s Day card best expresses your affection or trying to remember what type of flowers your loved one prefers. While speaking from the heart is important, you should also consider what your heart is putting out.
Heart output, not the cathartic kind, is a very valuable measure for fitness training. VO2 Max is the gold standard in the fitness industry for measuring heart output. It quantifies the amount of oxygen your body is able to utilize during exercise. In other words, it gives an indication of the efficiency of your cardiorespiratory system (and therefore endurance capabilities). However, this measurement requires expensive equipment and is labor intensive. A cheaper alternative is to use your heart rate (in beats per minute).
Heart rate training has been shown to correlate with VO2 Max and will increase in a linear manner proportional to workload during aerobic activity. In other words, as your heart rate increases, so does your VO2 Max. Using heart rate, you can methodically alter your training intensity to meet your desired fitness goals. There are 5 different heart rate zones. Each zone has a different effect on how your body adapts to training.
How to Find Your Heart Rate
Finding your heart rate can be as simple and cheap as checking your pulse or as complex and expensive as a Garmin heart rate monitor. After establishing your method of heart rate measurement it is necessary to determine your maximum heart rate and then calculate the appropriate training zone.
2 Main Ways to Find Your Target Heart Rate Zone
1) Age Predicted Maximal Heart Rate (APMHR)
220 -age = Maximum HR
Target HR = (APMHR x exercise intensity)
2) Karvonen Formula
This method involves using your resting heart rate to find your heart rate reserve (HRR)
MaxHR - Resting HR = HRR
HRR x exercise intensity = Target HR
Healthy Heart Zone (Warm-Up) = 50 - 60%
This is a great zone for you if you’re just starting to exercise. It can help to decrease body fat, blood pressure, and cholesterol.
Energy Efficient (Recovery Zone) = 60 - 70%
This zone has similar benefits to the heart healthy zone, but since it is done at a greater intensity it burns more calories. This zone develops basic endurance and aerobic capacity. For advanced endurance athletes this zone can be used as a recovery zone. During interval training this zone allows the muscles to restore the glycogen that is expended during the faster paced interval.
Aerobic Zone (Endurance Training) = 70 - 80%
This zone is necessary to train in if you want to increase your endurance. It develops your cardorespiratory system, increases the efficiency of your heart, and improves your aerobic capacity, meaning that the body has increased ability to transport oxygen to working muscles and to remove carbon dioxide.Anaerobic Zone (Performance Training) = 80 - 90%
This zone trains your fast twitch muscle fibers to develop speed and increases your VO2 Max. It works to increase your anaerobic threshold and increase the efficiency of your lactic acid system. This zone is mostly used for interval training and for experienced endurance athletes.
Red Line Zone (Maximal Effort) = 90 - 100%
This zone is very intense and can only be maintained for very short periods of time. You should consult a physician before training in this zone.
How to Train
Choosing which zone to train in depends on your fitness level and personal fitness goals. For novices it is important to start in a safe training zone that allows you to progress your endurance level without causing a musculoskeletal injury. For more advanced athletes it is advantageous to vary your training program and train in different zones. This can be done by performing intervals between zones or steady paced runs in one zone. Some studies have shown that using interval training with high-intensity training zones leads to the same endurance results in half the time when compared to steady state aerobic training.
Start at an intensity of 50-60% MHR and work your way up to a duration of 30 minutes. Once you can perform this without any problems you can progress to interval training. For intervals, perform exercise at 50-60% for 3 minutes, then increase the intensity to 60-70% for 2 minutes. Repeat for 30 minutes. You can progress the intensity as tolerated.
For Advanced Athletes the National Strength and Conditioning Association recommends a varied aerobic endurance training program such as the example below:
- Long Slow Distance = race distance or longer = 70-75% MHR
- Pace/Tempo = 20-30min = 75-85% MHR
- Interval = 3-5min (1:1ratio) = 80-90% MHR (60-70% MHR Recovery Interval)
- Repetition = 30-90sec(1:5ratio) = 90-100% MHR (60-70% MHR Recovery Interval)
- Farlek = 20-60min = varies between the above training methods
Increasing your endurance will lead to improved cardiovascular-repiratory-musculoskeletal health, increased oxygen delivery and utilization, improved fitness/endurance, and improved fat burning efficiency. Using your heart rate as a measure of intensity will give you a more accurate assessment of your training. By alternating your training with different heart-rate training zones you will allow for a greater aerobic performance.