people in a group fitness class

High-intensity fitness programs are designed to burn fat and build muscle fast by stressing muscles more than other workouts. These programs can include high-intensity interval training or HIIT classes, such as Tabata. However, if they aren’t done properly, these workouts can lead to muscle and joint injuries.

Before you think about starting high-intensity exercise, be sure you’re able to do it safely. Our sports medicine team has some guidance and effective alternatives.

What is an example of a high-intensity workout?

High-intensity interval training, better known as HIIT, consists of short bursts of intense work that typically last between 15 seconds to 4 minutes. These are followed by a quick recovery period and then right back to the tough work.

These cycles are repeated several times and can include a variety of exercises in each round. HIIT workouts can include the use of a stationary bike, treadmill, bodyweight, kettlebell, dumbbells, or jump rope. Another type of HIIT workout you may have heard of is called Tabata.

Read more: Tabata vs. HIIT: What’s the difference

What are the benefits of HIIT or other high-intensity exercises?

HIIT and other high-intensity exercise programs help you burn a lot of calories in a short amount of time. Research has also showed that you keep burning calories for hours after your workout is finished. These workouts typically cause you to burn more fat and build muscle. Studies have also showed that high-intensity workouts may help lower blood pressure and heart rate.

Read more: 7 Benefits of High Intensity Interval Training

Can high-intensity exercise really be dangerous?

The short answer is yes. However, the biggest danger to health is an inactive lifestyle, which is much more widespread than overdoing exercise. The goal should be to slowly overload the body for higher levels of performance, rather than to suddenly increase activity levels. While high-intensity exercise can lead to overuse injuries or muscle and joint injuries, these are less likely to occur with the right preparation.

Are there any fitness trends that concern you?

Any of the all-out group workouts that emphasize intensity instead of proper form and preparation can be a problem. These include programs that push you to do more sets and repetitions with heavier weights than you’re comfortable with. Exercise should make you feel some burn in your muscles, but it should never be painful.

Our UC Davis Health sports medicine physicians treat a lot of injuries related to these types of programs. Intensity can be great when done correctly. Too much, too soon is likely to cause problems.

Why is it a problem for an inactive or casual fitness person to do intense fitness activities?

The biggest issue is that moving regularly isn’t something most people do. This can leave people who try to get in shape quickly more prone to injury.

Inactive people who aren’t experienced with exercise or those who haven’t regularly exercised in a while tend to push themselves too much. In these situations, people often aren’t aware of how hard they can and should work. This is especially true for those who are doing a group workout.

Can high-intensity exercise improve fitness?

There are ways to mix in intensity and speed fitness, but that should not be the emphasis for most people. Start by moving more than you normally do throughout each day. This is more beneficial than a one tough workout every so often. At the same time, people who have been doing the same exercises for months are unlikely to get more fit unless they make changes. This could include changing their routines, pushing harder, and working beyond their comfort zones.

What are some signs that you’ve gone too far with a workout?

Pain is a big sign that a workout is causing trouble. If any exercise causes pain, don’t push through it. It’s a good idea to start slowly increasing physical activity and intensity. This will allow you to learn the difference between pain and being uncomfortable.

What are some tips for someone who is inactive but wants to be fit?

Most everyone can be physically fit and able to do the workout they want without going too far. However, you need to think long term. Properly preparing your body for movement is key.

Focus on improving your mobility, stability, strength, and cardiovascular fitness. This will eventually allow you to do any physical activity you choose. Before diving into tough exercise, spend six to 12 months (or more) doing the following:

Putting in time on the front end will better prepare your body for fitness, while reducing injuries.

UC Davis Health fitness programs to help you

These programs and assessments will help get you to your next fitness level:

  • Sports injury prevention can help you meet your personal fitness goals while working to prevent injuries.
  • Comprehensive fitness assessment designed to provide an overview of your fitness level, followed by recommendations for improvements.
  • Metabolic testing helps you accurately estimate how many calories you’re burning, which is valuable in any plan to lose, maintain, or gain weight.

Check out more from the UC Davis Sports Medicine Learning Center

This blog was reviewed by Judd Van Sickle, who manages the sports performance program for UC Davis Health. He guides everyone – from those just getting started with exercise to professional athletes – on ways to improve their fitness.