Pete McCall by Pete McCall

No one goes to a health club or fitness studio hoping they leave in worse shape than when they arrived. There is one common denominator shared by everyone who exercises on a regular basis: we all want results from our time spent sweating! This is one reason why high-intensity interval training (HIIT) workouts have become so popular over the past number of years; simply put, they work! HIIT workouts are designed to push you to your physical limits, where you’re constantly sweating, out of breath and feeling downright uncomfortable. As instructors often say, “If it doesn’t challenge you, it won’t change you.”

Yes, HIIT workouts work and can be very effective for burning a lot of calories in a relatively short amount of time. But does exercise really have to be so hard or uncomfortable to be effective? Do you really need to work at an extremely challenging intensity every time you exercise? The good news is that the answers are no and no.

HIIT, while effective, could have a number of negative consequences that could actually keep your clients from getting the results they are working toward. This doesn’t mean that you should avoid using HIIT with your clients; rather, it’s a much better idea to limit high-intensity workouts to three or fewer times per week for those who are age 35 and younger, and two or less for those who are older than 35. The reality is that fitness improves after the workout, not during it. If people constantly hammering as hard as they can with every workout, they aren’t allowing their bodies the necessary time to experience optimal recovery.

If you or your clients are not already doing some form of sub-maximal, steady-state aerobic conditioning, consider adding it to your current workout program. There are a number of differences between HIIT and steady-state training (SST) that have already been discussed in a previous post (read it here). The purpose of this blog is to highlight six benefits of sub-maximal SST to help you decide whether or not you should make it a regular component of your clients’ long-term workout programs (hint: you should).

1. One of the biggest benefits of SST is strengthening the heart.

Your heart is simply a muscle with the function of pumping blood through your entire body. One of the biggest benefits of SST is strengthening the heart so that it becomes more efficient at doing its job. The lungs pull oxygen in from the air and place it in the bloodstream, and the heart is responsible for pumping the oxygenated blood around the body to the working muscles. Maintaining a steady state in the aerobic zone can help the body become much more efficient at pumping oxygenated blood to the working muscles and moving the deoxygenated blood back to the lungs to remove the carbon-dioxide and be reoxygenated.

2. To optimize aerobic efficiency during exercise, stay at an intensity where breathing is quick, but under control. 

You can easily determine the appropriate intensity for optimal aerobic efficiency by using the science behind the Talk Test. The Talk Test is the foundation for programming in the cardiorespiratory component of the ACE IFT Model of exercise program design. When you can talk during exercise, you are working at an intensity where the aerobic energy system is using oxygen to help metabolize fat into energy to fuel muscle activity. As exercise intensity increases, energy demands become more immediate and the body will start using stored carbohydrates (glycogen in the muscle cells) to supply energy. As work increases, the body needs more oxygen and, because it’s burning more carbohydrate, is expiring (breathing out) more carbon dioxide. This, in turn, increases breathing rate, which limits the ability to talk. To optimize aerobic efficiency during exercise, urge your clients to work at an intensity where breathing is quick, but under control, and where they can talk without too much difficulty (i.e., on a scale of 1 to 10, where 10 is the hardest, this would be about between 5 and 6). Staying at this intensity optimizes aerobic efficiency instead of simply trying to work as hard as possible.

3. Aerobic SST can help the body become more efficient at using fat to fuel muscle activity.

At lower intensities, the body will metabolize free fatty acids (fat) as the primary source of fuel. As mentioned above, at higher intensities the body relies on carbohydrates for energy, and high-intensity workouts that deplete muscle glycogen will, over time, cause adaptations to your muscles so they can store more glycogen for future high-intensity workouts. Training at a lower intensity using the aerobic energy pathways helps the body become more efficient at lipolysis, which is the breakdown of fatty acids (lipids) into energy (in the form of adenosine triphosphate, or ATP).

4. Because SST is less physically demanding than HIIT, exercising to improve aerobic capacity could help reduce one’s risk of injury.

As energy depletes during high-intensity exercise, there is a tendency to lose form or technique, which could be a cause of injury. However, SST also poses the risk of overuse injury if the same exercise is performed repeatedly. For the best results from SST, it’s a good idea to switch modes of exercise so that you do not overuse any muscles. When working with clients in a health club, have them switch machines (e.g., stationary bike, treadmill, stair climber, rowing machine, elliptical trainer) every 10-12 minutes to help break of the monotony of SST and reduce the stress on any single joint or muscle group. The goal is to maintain the same level of intensity (5-6/10) on each piece of equipment and accumulate a total of 30-60 minutes for the entire workout.

5. SST in the aerobic zone is important for cellular health. 

For example, SST can increase the number of mitochondria in muscle cells (mitochondria are the components of the cell that help convert oxygen to fuel). Over the long-term, increasing the amount of mitochondria in muscle cells helps improve overall aerobic efficiency and cellular function, and may also mitigate the effects of the normal, biological aging process.

6. SST can help with active recovery from harder, more-challenging workouts.

Lower-intensity aerobic conditioning, around 4-5/10, will help remove metabolic waste while delivering the nutrients that can help repair the muscles used in the previous day’s workout. Even if mildly sore, SST in the aerobic zone can help the body fully recover and prepare for the next hard workout.

When it comes to deriving long-term benefits from exercise, it is better to train smarter as opposed to simply push the body to work harder. Knowing how to properly organize your clients’ long-term fitness programs by alternating between low-, moderate- and high-intensity workouts are the real secrets to achieving long-term success from exercise.

ACE’s Personal Trainer Certification is backed by 30 years of science-based research. Learn more.