High Intensity Exercise: What It Is and How to Do It Safely

Intense exercise is a type of activity that involves short bursts of hard work followed by longer periods of rest or easy work. It can help you improve your health and fitness in many ways, but it also has some risks that you need to be careful of1. In this article, we will explain what intense exercise is, why you should do it, what are the risks, and how to do it safely2.

What is Intense Exercise and Why Should You Do It?

Intense exercise is also known as high-intensity interval training (HIIT) or sprint interval training (SIT). It is a form of exercise that alternates between short periods of high effort and longer periods of low effort or rest3. For example, you can run fast for one minute and then walk for two minutes, and repeat this cycle for 10 to 30 minutes4.

Intense exercise can help you improve your health and fitness in many ways, such as:

  • It can make your heart and lungs stronger and healthier by increasing the amount of oxygen they can use and lowering your blood pressure and cholesterol levels.
  • It can boost your metabolism and fat burning by making your body use more energy and hormones that break down fat cells even after you finish exercising5.
  • It can make your muscles stronger and faster by activating the muscle fibers that are responsible for power and speed and improving your coordination and balance.
  • It can save you time and money by requiring less equipment and time than traditional exercise methods.

What are the Risks of Intense Exercise?

Intense exercise is not for everyone, and it can have some negative effects if you do it wrong or too much. Some of the risks of intense exercise are:

  • It can increase your chance of getting injured by putting too much stress on your joints, muscles, and tendons, or by doing the exercises with bad form or technique6.
  • It can cause you to overdo it or burn out by doing intense exercise too often or too hard, or by not giving yourself enough time to recover between sessions7.
  • It can harm your health or performance by causing inflammation, stress, or immune problems, or by affecting your sleep quality or appetite.

How to Do Intense Exercise Safely?

To do intense exercise safely and effectively, you need to follow some basic rules, such as:

  • Choose an exercise that you like and that matches your fitness level and goals8. You can use any machine that makes your heart rate go up, such as a treadmill, bike, or rower, or you can do exercises that use your own body weight, such as burpees, mountain climbers, or jumping jacks.
  • Set up your workout plan by deciding how long and how hard you will work and rest. A common way is to work for one minute and rest for two minutes. The hard periods should be shorter than the easy or rest periods, and the total workout time should be between 10 and 30 minutes9.
  • Monitor your effort level by using a device that measures your heart rate or a scale that measures how you feel. Your heart rate should be between 80% and 95% of the highest rate your heart can beat during the hard periods, and between 40% and 60% during the easy or rest periods. You can estimate the highest rate your heart can beat by subtracting your age from 220. Another way is to use a scale that goes from 1 to 10, where 1 is very easy and 10 is very hard. You should feel between 8 and 9 during the hard periods, and between 4 and 5 during the easy or rest periods10.
  • Warm up and cool down before and after your intense exercise session by doing some light exercise and stretching for at least 5 minutes each. This will help you prevent injuries and improve your recovery.


Intense exercise is a great way to improve your health and fitness in a short amount of time, but it also has some risks that you need to be aware of and avoid. By following the rules above, you can do intense exercise safely and effectively, and enjoy the benefits of this challenging and rewarding activity2.