If you are a gym enthusiast, an athlete or have ever exercised in your life, then you would realize that your heart rate increases when you exercise. Even when you halt your exercise, your heart rate does not return to normal instantly. So why does the heart beat faster when you exercise?
Some people may be worried about it, but truth be told, most of the time it should not be a cause for uproar. The body needs more nutrients and produces more wastes as the muscle activity increases. The body responds to these changes by increasing the speed at which the heart beats.
The body muscles require more oxygen and energy during exercise. The blood vessels supplying the active muscles expand to allow for more blood and nutrient flow to the muscles. As these blood vessels expand, the vessels in the kidneys and stomach constrict.
However, more blood vessels expand than contract, requiring the heart to pump more blood. As a result, a faster pulse is triggered so as to maintain a healthy blood pressure.
Intense exercise causes the body muscles to produce large volumes of waste in the form of carbon dioxide, hydrogen ions, adenosine and lactic acid. The accumulation of these wastes in the body can at times be fatal. For instance, too much lactic acid in the body can lead to acidosis.
Acidosis is usually as a result of pH imbalances in the body organs and leaves you at risk of catching a migraine, lack of appetite and fatigue.
The increased heart rate during exercise produces a faster blood flow rate which allows the blood to sweep these wastes away from the muscles and excrete them through urination, sweating or exhalation.
The body’s sympathetic and parasympathetic nervous systems are responsible for controlling the rate at which your heart beats. Just before an exercise session, the heart rate is normal. As training begins, the sympathetic nervous system triggers your heart to beat faster in response to the body’s demands
In most cases, exercise involves vigorous activity that increases the energy demands for the muscles. Although anaerobic metabolism can produce some energy, most of the muscle’s energy needs are fulfilled by aerobic metabolism which requires oxygen.
Since the bloodstream is responsible for supplying oxygen to the muscles, your heart must pump a large volume of blood to maintain the necessary oxygen supply for the muscles to remain active. For a healthy oxygen supply to the muscles, your heart starts beating forcefully and rapidly, which increases the heartbeat.
Besides, if you’re training on a hot day, the high temperatures coupled with rigorous heart activity will increase the heart rate substantially. This occurs because the heart needs to supply blood to the skin to cool you down. This change will require the heart to beat quicker than usual.
We are well aware that the heart rate increases because the heart needs to deliver more oxygen to the body muscles. But what more will exercise do to your heart?
When you engage in cardiovascular exercises, blood flow is channeled towards the working muscles, away from parts that are not working hard as much (like the digestive tract). The blood volume increases and subsequently, blood flow returning to your heart increases.
When the heart registers a significant amount of blood, the left ventricle starts adapting to the change and increases in capacity. This larger cavity can now hold and pump more blood with a beat, even when you are resting.
Consistent cardiovascular training results in a decrease in the heart rate when resting since every beat delivers a large volume of blood, which is why fewer heartbeats are needed. This relieves the heart a huge burden, which is why cardio exercises are the best for a healthy heart.
Strength training exercises work the heart differently from cardiovascular exercises. In strength training exercises, specific body muscles are always contracting, and as a result, blood vessels flowing through the muscles are pressed and blocked.
This builds up pressure in the circulatory system, requiring the heart to fight hard to push the blood. With time, new blood vessels and capillaries are formed, which facilitates better blood circulation.
A faster heart rate when exercising should not be a cause for alarm because it is just one of the numerous mechanisms the body adopts to meet its oxygen requirements and energy demands. This is just a short term change meant to keep your muscles running as you perform your fitness regime.
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