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# Heart rate and self-defense

## Intro

Heart rate has a great influence on your ability to respond to a self-defense situation; more influence than most martial artists realize.

## Definitions

First, some heart rate definitions:

### Heart rate

Heart rate is a term used to describe the frequency of the cardiac cycle. It is usually calculated as the number of contractions of the heart (heartbeats)in one minute and expressed as "beats per minute" (bpm).

### Resting heart rate

When resting, the average adult human heart beats at about 70 bpm (males) and 75 bpm (females); however, this rate varies among people and can be significantly lower in athletes.

### Maximum heart rate (also called MHR, or HRmax)

This is the maximum heart rate that a person should achieve during maximal physical exertion. Research indicates it is most linked to a person's age; a person's HRmax will decline as they age.

The most accurate way of measuring a person’s HRmax is via a cardiac stress test where the person exercises while being monitored by an electrocardiogram (ECG). During the test, the intensity of exercise is periodically increased until the subject can no longer continue, or until certain changes in the heart’s function are detected in the ECG. Since the HRmax declines with age, the test results will change as we get older.

To estimate your HRmax, the most common formula used is: HRmax = 220 – your age. However, a more accurate formula is: HRmax = 205.8 − (0.685 * age). These figures are still dependent on your physiology and fitness. For example, an endurance runner's rates will typically be lower due to the increased size of the heart due to the long duration runs, while a sprinter's rates will be higher due to the improved response time and shorter duration runs.

### Recovery heart rate (RHR)

This is the heart rate measured over a 15-second interval, taken 2–10 minutes after exercise. The goal is not to exceed 150 bpm. A drop of 20 beats in a minute is typical for a healthy person. A drop of fewer than 12 beats per minute after maximal exercise has been correlated with a significant increase in mortality.

### Target heart rate/Training heart rate (THR)

This is the desired range of heart rate to reach during aerobic exercise; it enables the person’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.

The following are two ways to calculate your THR. In each, there is an element called "intensity," which is expressed as a percentage. THR may be calculated by using a range of 50%–85% intensity.

#### Karvonen method

This method factors in resting heart rate (HRrest) to calculate target heart rate.

The formula is: THR = ((HRmax – HRrest) × %Intensity) + HRrest

Example for someone with a HRmax of 180 and a HRrest of 70:

At 50% intensity: ((180 − 70) × 0.50) + 70 = 125 bpm
At 85% intensity: ((180 − 70) × 0.85) + 70 = 163 bpm

This method derives exercise zones by subtracting values from HRmax. The higher the zone number, the tougher the exercises being performed.

The formula is: THR = HRmax – Adjuster ± 5 bpm

Exercise zones (easiest to most difficult)

Zone 1 Adjuster = 50 bpm
Zone 2 Adjuster = 40 bpm
Zone 3 Adjuster = 30 bpm
Zone 4 Adjuster = 20 bpm
Zone 5 Adjuster = 10 bpm

Example for someone with a HRmax of 180:

Zone 1 (easy exercise): 180 - 50 = 130; ± 5 → 125 to 135 bpm
Zone 4 (tough exercise): 180 - 20 = 160; ± 5 → 155 to 165 bpm

### Heart rate reserve (HRR)

HRR is a term used to describe the difference between a person's measured or predicted maximum heart rate and resting heart rate. Some methods of measurement of exercise intensity also measure the percentage of heart rate reserve. As a person increases their cardiovascular fitness, their HRrest will drop, thus the heart rate reserve will increase. The percentage of HRR is equivalent to the percentage of VO2 reserve. The formula for determining HRR is: HRR = HRmax – HRrest

## Heart rate as it relates to self-defense

How does your heart rate affect your ability to defend yourself? Once the central nervous system senses you are in a stressful situation, it accelerates the heart rate, constricts blood vessels, and releases the stress hormones, epinephrine, and norepinephrine, into the bloodstream to prepare the body to fight or run away. Once the central nervous system detects that the body has exceeded HRmax, it assumes we are in extreme danger and have lost control of the situation, and it performs a “hormone dump” where it pumps a cascade of the hormones into the bloodstream to help the body deal with the emergency.

Most people, even martial artists, have seldom, if ever, been in a situation that would drive them into HRmax so they do not know how to deal with its effects. The hormone dump brings out instinctive behaviors that are commonly known as the “fight or flight” reflexes. The body prepares itself to fight, run away, or it may simply freeze and not move at all. When this occurs, conditioned skills, such as our martial art skills, are suppressed and our techniques are slower, weaker, and uncoordinated.

Some of the effects of a hormone dump are tachipsychia (the feeling of time being altered), auditory exclusion (only hearing what needs to be heard), visual exclusion (tunnel vision, only seeing what needs to be seen), tone amplification (screaming), teeth-baring, snarling, fist-clenching, and short-term memory exclusion. These reflexes were useful for our ancestors when they had to deal with predators. They can still be useful, but sometimes they cause problems when dealing with modern threats. The fight and flight reflexes still have relevance in self-defense situations, but the freeze reflex, which once made us undetectable to predators with bad vision, has little relevance today. For example, think about what would happen if you froze under the stress of having just stepped in front of a fast-approaching truck.

### Reaching HRmax

When we have trained to deal with the unexpected, such as in martial arts training, we lessen the chances of reaching HRmax. Since our training is useful in handling such things as an unexpected attack, we may never reach HRmax, but when things start to go bad, such as being cut by a knife, even the best-trained people may go into HRmax. When we exceed HRmax, the central nervous system thinks we are unable to handle the situation with our martial art skills and it allows our basic instincts to take over. When this occurs, our martial art skills may become ineffective.

A martial artist who is in poor physical condition may reach HRmax more quickly than a highly conditioned fighter. Regrettably, many martial artists, especially those over 30 years of age, are not in great physical condition. Years of practicing the same techniques over and over have not only made them good at doing the techniques, it has made them more efficient at doing the techniques, therefore, less physical conditioning is needed to perform the techniques. This means they will reach HRmax sooner and the skills they have so diligently practiced will be inhibited.

Most martial artists train to perfect their physical techniques, and some train to improve their concentration and relaxation skills. However, few martial artists train to handle stressful situations. People in high-stress office jobs can handle stress better than most martial artists. As a result of their reduced stress management skills, many martial artists will panic in high-stress situations, go into HRmax, and their martial art skills will falter.

Most martial artists train to perform techniques and the perfection of those techniques. However, bad guys could care less about perfect techniques, the only thing that impresses them is pain–whether your techniques cause them pain and how much pain they may inflict upon you. Since many martial artists do not train in conflict management and do not know how to deal with violent attackers, they are surprised by how quickly a person may become angry enough to attack and how aggressively and violently a seemingly mild-mannered person may attack. As a result, when these attacks occur, these martial artists go into HRmax and lose the ability to use their martial art skills.

Many martial artists have outstanding physical conditioning. The problem is that the conditioning relates to their martial art; they have only trained to be good at their martial art. When faced with a situation outside the realm of their martial art, their conditioning level may not be sufficient to handle it. A professional football player can take a pounding in a game on Sunday and be fine the next day. However, if the same player plays a few sets of tennis for the first time with his girlfriend, the next day he will probably ache all over since he used muscles he was not accustomed to using. Fighting an opponent in the ring, no matter the level of contact, is not that stressful for a fighter since he or she has trained for it and knows there are rules, referees, and available medical services. However, in self-defense situations, there are no rules, referees, or medical help. Thus, when faced with this type of situation, even a martial art champion may quickly go into HRmax and get slaughtered.

### All is not lost

Going into HRmax is not a death sentence; you will still have your instinctive fighting skills and access to some of your martial arts training. Also, with proper training in recovery techniques, you will be able to lower your heart rate, come out of HRmax, and gain some control of the situation. Professional fighters train in relaxing and recovery during the short one-minute between rounds. Many times, a fighter who is seemingly wasted at the end of a round will come back strong after only a minute rest.

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