How does heart rate increase? Does it double? Does it increase with the intensity of the workout?

I already know the background of heart rate but have trouble with the questions above.

Your body needs oxygen in order to efficiently break down glucose and process it into your cell's primary energy source (ATP). As you do more intense exercise, you need more energy and therefore more oxygen. Your blood carries oxygen from the lungs to your muscles. To keep up with these increased oxygen needs, you have to have more blood going to your muscles. As a result, your heart pumps faster, sending more oxygenated blood to your muscles per second.

btw this is from wiki answers

Heart rate increases through a process known as heart rate elevation, which is a natural response to various factors such as physical activity, emotional state, or stress. It is not fixed or predetermined, but rather dynamic and adaptable to the body's needs.

During exercise, heart rate typically increases to meet the demands of the body. The increase is proportional to the intensity of the workout. The heart works harder to pump oxygenated blood to the muscles, which need more energy during physical exertion.

The increase in heart rate during exercise varies from person to person. While it is challenging to determine an exact formula to calculate heart rate increase, it can be estimated using the maximum heart rate (MHR) formula. The MHR is approximately 220 minus your age. For example, if you are 30 years old, your estimated MHR would be around 190 beats per minute (bpm).

During light to moderate exercise, your heart rate will typically increase to around 50-70% of your MHR. With moderate to vigorous exercise, it can reach 70-85% of your MHR. Consequently, during intense workouts, heart rate can reach higher percentages of the MHR, but it is uncommon for it to double.

It's important to note that individual factors, such as existing cardiovascular conditioning, fitness level, and overall health, can influence heart rate response during exercise. It is always advisable to consult with a healthcare professional or a certified fitness trainer for personalized guidance regarding heart rate during exercise.