WAYS TO CHANGE YOUR HEART RATE
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There are a number of different factors that affect the control and response of heart rate. But, what controls the beat of the heart?

1. Environment Stresses:

Heart rate is affected by external stresses on the body such as heat, humidity, cold, wind, and altitude and air quality. With each stress, the human heart is affected and different compensatory changes occur, one of those being adjustment in the beat of the heart. Triathletes racing at the Hawaiian Ironman face most of these conditions simultaneously while racing in one of the most strenuous events in the world. As a result, a heart rate monitor can help provide them with key information on how their body is responding to the conditions and the duration of this high intensity racing throughout the event.

The following chart shows the affects on heart rate of certain environmental stresses:

Type of Stress	Specific Stress	Heart Rate Changes	Explanation
Thermal Stress	Heat gain*	Elevated	Changes in heart rate are the result of changes in the core body temperature. Dressing appropriately is the most important consideration to maintain the bodies core temperature. Dehydration causes heart rate to increase.
	Heat loss	Lowered	Thermoregulation adjustments result in improved exercise capacity to heat exposure but minimally to cold stress. This generally takes about 10 days. Shivering can increase the heart rate significantly to increase core temperature. Considerable water can be lost from the respiratory tract during cold exposure when exercising which results in elevated heart rates (dehydration effect on heart rate).
Humidity	Dry Air	Elevated	The water content in the ambient air affects the amount of water lost through sweating. In dry air, sweating can be profuse and decrease in blood volume from dehydration substantial. Each 1 pound of body weight loss corresponds to 15 ounces (450 mL) of dehydration. Hot dry climates are easier than humid ones because evaporation of sweat, which cools the skin, can be achieved.
	Highly moist air	Elevated	Exercising in high humidity challenges the thermoregulatory system because the large sweat loss contributes little to evaporative cooling. Sweat does not cool the skin; evaporation of sweat cools the skin. Heart rate response is to increase blood flow to the skin for sweating therefore increasing heart rate.
Wind	Wind Chill	Lowered and Elevated	Wind caused by physical movement or air movement magnifies heat loss as the warmer insulating air on the skin is continually replaced by cooler, ambient air. Wind causes heat to decrease and hence heart rate to stay lower. Wind chill factor is an index that shows the effect of wind velocities on bare skin for different temperatures.
Altitude	High	Lowered maximum and training heart rates	There is a progressive reduction in the amount of oxygen and it’s partial pressure as altitude increases. As a result, the heart beats faster to compensate for less oxygen per breath. Maximum heart rate drops with increases in altitude approximately one beat per 1,000 feet of gain. There is some relief from the acclimatization process, which result in improved tolerance to altitude hypoxia.

* Same response to thermic effect of food

 

2. Internal Body Changes

Almost any substance taken into the body affects the equilibrium of the organism. Heart rate is one of the quickest changes that occur as a direct reflection of this change that results in disequilibrium. For example, beta blockers (Inderal, Propranolol, Lopressor, etc.) cause bradycardia or the heart rate to drop. Similarly, the antiarrhythmic agents (Cardioquin, Procaine, Quinidine, etc.) given to patients to improve cardiac function also causes a decrease in heart rate. Pulmonary bronchodilator drugs such as the sympathomimetics (Isoproterenol, Ephedrine, Bronkosol, etc.) cause tachycardia or increase in heart rate values. Drugs that act as stimulants such as caffeine, nicotine, methamphetamines, cocaine, PCP cause tachycardia and drugs that are depressants, barbiturates, tranquilizers, alcohol and quaaludes cause bradycardia. Some drugs like inhalants can cause either a quickening or depressing of heart rate and respiration.

Other changes can cause changes in heart rate. Lack of sleep, irritability, rapid changes in blood chemistry such as blood sugar levels, reactions to different types of ingested foods can both lower and raise resting and exercising heart rates. Emotions play a large role in heart rate response. Anger, fear, and anxiety cause tachycardia while depression usually results in lowering of heart rate. Feelings of love, compassion, happiness usually result in braycardia. Emotional stress causes heart rate to stay elevated.

3. Fitness Level

The fitter you are the less often your heart contracts thus saving heartbeats. Getting fitter is like putting money into your saving account, it’s putting heartbeats into your physiological saving account. Through the phenomenon of the training effect, ambient and resting heart rates drop, by as much as 20-30 bpm. When extended over a lifetime, this can equate to hundreds of millions of heartbeats.

The athlete’s heart as the fit cardiac muscle is sometimes referred to is different than the sedentary individuals cardiac pump. There are structural and dimensional changes to the hearts of athletes, which reflect the specific training demands. The effects of getting a fit heart leads to cardiac hypertrophy, a muscle adaptation as a result of increased work capacity. That is, there is a moderate increase in heart size and anatomies regardless of age as the result of an aerobic and anaerobic training program.

Here’s a list of changes that happen to the fit, athletic heart muscles:

Improved cardiac output         Lower resting and ambient heart rates

Increased stroke volume         Enlarged ventricular chamber

Thickening of the heart walls Improved coronary blood flow

Improved mitochondria mass Increase number of respiratory enzymes in the myocardium

Protection from the degenerative process of heart disease

The state of fatigue or rest of the individual also affects heart rate. If a student is physically tired from over-exercising there is a decline in physiological performance. Overtraining is a complex series of conditions which can include nutrient-fatigue, muscle-fatigue, and neuromuscular-fatigue. Heart rate is affected differently by different kinds of fatigue.

Heart rate is not affected by body composition. It’s not affected by body type. It is affected by heart size with smaller hearts typically having higher resting and ambient heart rates.

4. Genetics

The genes that you inherited are responsible for much in our lives. They too affect heart rates. It appears that the effect of your genetic makeup accounts for about 50% of the value of your maximum heart rate. This means that if your parents both have a low maximum heart rate, the odds are favorable that you will as well.

5. Mode of Exercise

That’s even more of a reason to use a heart rate monitor. It’s a management tool. The heart muscle takes all of these situations and conditions into account when it sets the frequency of the beat. Both the heart muscle and the heart monitor are powerful – use them both, together.