Interval Workouts Explained: How and Why They Outperform Steady State Cardio

Moving your body on a regular basis is key for health and longevity. But did you know that getting out of your comfort zone and into higher heart rate zones has added benefits? Here are three reasons why high intensity training is so powerful, what true HIIT and SIT looks like, plus sample (equipment-free) workouts for you to get started with. Let’s dive in.

There’s no need to essentially make yourself less fit, strong, and healthy by avoiding high intensity exercise!

-Dr. Stacy Sims

Why Interval Training is Effective

Cortisol Production

Cortisol is a stress hormone that is essential for exercise.

You know the feeling (hopefully!) when you begin moving. Your heart starts beating fast, your breathing becomes labored, and you heat up and start to sweat. Cortisol elevates in order to help our body regulate itself.

Chronically high cortisol levels can be detrimental to our health. Even though exercise causes a spike in cortisol, the right type of exercise can actually cause overall levels to decrease.

When women do high intensity interval training (HIIT) and sprint interval training (SIT), cortisol is released, and over time, as long as you continue to train this way, overall cortisol levels go down. This does not happen to men and this does not happen when women do low-mid intensity cardio. It only happens when women do true high intensity exercise (HIIT and SIT).

So save the long duration (45 minutes plus) low-mid intensity (heart rate zones 1 and 2) workouts for social time or just for the fun of it. Use the HIIT and SIT intervals to create positive changes in your body composition, fitness capacity and stress levels.

Brain Health

You’ve probably heard about lactate (or lactic acid) – the chemical produced by your muscles during a tough workout. Many believe that lactic acid is responsible for muscle soreness after a workout, but this is actually not true! Lactate is an important fuel source for muscles during exercise, and is usually cleared out before soreness even begins.

I bring up lactate not only to clear up that common misunderstanding, but to talk about how the production of lactate impacts the brain.

Louisa Nicola is a neurophysiologist and leading researcher on Alzheimers Disease. Here’s what she has to say about lactate and brain health:

“Lactate, often associated with muscle metabolism during exercise, also plays a pivotal role in brain metabolism. Recent research indicates that lactate produced during strenuous aerobic activity is not merely a waste product but a valuable energy source for the brain. It is transported to the brain via the bloodstream and is used by neurons as an energy substrate, particularly during periods of intense activity. This utilization of lactate by the brain underscores the interconnectedness of physical exercise and cognitive function.”

The best exercise for your brain is, as she states, “intense activity.”

This is not to say there aren’t above the neck benefits associated with low intensity activity. But high intensity workouts will protect your brain in ways that no other type of exercise will.

Work on Your Weakness

Women, by nature, have more Type I (slow twitch) muscle fibers. These types of fibers have a high oxidative capacity and have more mitochondria than other types. Mitochondria are the organelle responsible for respiration and energy production within the cell.

A prevalence of Type I fibers means women are well equipped for long aerobic activities such as walking, running, cycling, and swimming. 45 minutes or more at a conversational pace is our wheelhouse, ladies! We are predisposed to be strong endurance athletes.

It’s crucial we polarize our training and work our bodies in a different way by ramping up the intensity at least a couple days a week.

Power and speed are on the other end of the performance spectrum and require Type II (fast twitch) muscle fibers. Women benefit from doing workouts that improve our fast twitch fibers because that’s where we’re lacking. Hello sprint intervals!

Now that you know the WHY behind this type of training, let’s discuss the HOW. Here is a sample HIIT and SIT workout requiring zero equipment.

Important Disclaimer: If you are new to higher intensity workouts, start slow and take time to adjust to the demands of training this way. Consult your doctor before beginning a new exercise routine.

Sample Workouts

Bodyweight HIIT Workout

Movements

Station 1 – Mountain Climbers

Station 2 – Squats or Jumping Squats

Station 3 – Burpees

Station 4 – Lateral Lunges or Skaters

Station 5 – REST

Intervals / Intensity

Stations 1,2,3,4 – work for 50 seconds at 80% of max, rest for 10 seconds

Station 5 – Rest for one full minute

Cycle through 2-5 times.

An 80% effort is a 6-9 on the rating of perceived exertion.

Bodyweight SIT Workout

Movement

Choose an activity that you can safely do at a max effort. It doesn’t have to be sprinting, but could be. It could be running uphill or doing stairs. If you’re proficient at burpees it could be those, or a variation on them. I’m a fan of using an air bike for SIT intervals because most people can safely achieve the intensity required on a bike.

Intervals / Intensity

Work at a max (all out) effort for 30 seconds.

Rest for 2-3 minutes

Repeat up to 8 times.

This is at a level 10 on the RPE Scale.

Be sure to follow our social media. I will be posting videos that go over the above workouts with exercise demos and options for making them work for you!