Hi there! Happy Friday to everyone. I’d like to talk today about the beauty of interval training, and the benefits it has over chronic cardio training, such as marathon running or long-distance biking or hours of swimming laps. I recently started interval training after reading through several pages about how spending more time exercising isn’t exactly the most efficient way of losing weight. In fact, you can spend less time exercising and reap grater benefits than you might if you spend an hour on the treadmill each day.
(Keep in mind, I’m not a doctor and I’m not a licensed nutritionist, and what you read here can always be taken with a grain of salt. Do your own research, talk to your own doctor, and find the routine that works best for you. Now, onto my point…)
Stop! Step Away From theTreadmill!
Conventional “wisdom” about fitness and heart health claim that the more you exercise, the more calories you’ll burn and the more weight you’ll lose; consequently, the more you exercise, the healthier your heart will be. Sound familiar? This has been the main talking point for calorie-counters for as long as calorie-counting has been a thing, and it generally follows the same line of thought that promotes the idea of “calories in, calories out, ” with little regard to the type of calories being brought in (and therefore, the different metabolic processes for different types of nutrients) or the ways in which they’re being burned, or “pushed out.”
Following this line of thought, conventional wisdom might claim that marathon runners, triathlon competitors and iron men are some of the fittest individuals to walk the planet. It’s probably true that the people who do these sorts of things are hardwired in a way that allows them a competitive advantage; if they were no different from the rest of us, we’d all be iron men and iron women. But that’s not the case, now is it?
Anyway, it may be true that these people have super strength, super endurance and super motivation. Their bodies must be totally efficient and healthier than the rest of us, right?… Alas, conflicting research begs to differ.
When we exercise, we’re literally putting our bodies through periods of stress. Your muscles require more oxygen to keep you moving, which requires extra effort from the heart, which has to pump a lot faster to keep up with the demand. Think of the fight or flight response: in these moments, when you sense danger, your heart rate increases, getting you ready to flee if necessary, increasing your stress for those moments when you perceive a threat. This sudden stress response releases a wave of cortisol into the body, which gives you a burst of energy to help you get away from the danger. Once the threat is gone, your adrenaline decreases and your stress levels go down. Now, imagine suspending that level of stress for an hour or more, as you would while running or biking or swimming for long periods of time. Doesn’t sound too good, does it?
While short periods of stress are natural and necessary for basic bodily functions, chronic stress is harmful, and can lead to myriad problems, such as illness, injury, mental and emotional disruptions, difficulty losing weight and damage to the heart. You see, running 26 miles straight through puts your body under an extreme amount of stress, just like the fight or flight response; this results in an increase in cortisol levels, reduced testosterone levels (which is essential for muscle growth in both men and women), and greater vulnerability to illness and injury. But you don’t have to run 26 miles to create these increased levels of stress in the body. In fact, research suggests that doing more than an hour of continuous cardio each day will bring you into that danger zone.
A few of the dangers of excess cortisol in the body resulting from chronic stress include the following:
- Excess cortisol reduces protein synthesis, which is a fancy way of saying that it stops your body from growing new tissue (such as muscle tissue) – in fact, it will break down muscle tissue, which is NOT what you want if you’re looking to get results from weight training (which we should all be doing, by the way)
- Excess cortisol lowers testosterone in men and women alike, which can affect mood and libido, as well as muscle growth.
- Immune functions decrease, leaving you vulnerable to more illnesses (how many of you have met marathon runners who get sick with colds on a regular basis? I’ve known a few)
- You start craving carbs (which, as we know, are already bad for you)
- Hypertension, insulin resistance
- Bone loss
This article in the Daily Mail reports on findings that claim that excess exercise can actually change the structure of your heart (and not in a good way.) From the article,
“Dr O’Keefe and colleagues said research suggests that extreme endurance training can cause transient structural cardiovascular changes and elevations of cardiac biomarkers, all of which return to normal within one week.
But for some individuals, over months and years of repetitive injury, this process can lead to the development of patchy scarring of certain areas of the heart, and abnormal heart rhythms.”
Basically, excessive cardio routines have the ability to damage the heart and, if repeated over years, can lead to scarring of the heart tissue and an abnormal heartbeat. Not exactly something a fitness enthusiast should aim for, huh?
In addition to the dangers of chronic cardio and the resulting stress levels, it’s a highly inefficient way of trying to lose weight because, as you expend that energy, the more energy your body will crave as a result. So what do you do after running on the treadmill for 45 minutes? You go home and eat a big meal, which can potentially lead to a “canceling out” of those burned calories. This type of cardio doesn’t enhance metabolic processes after-the-fact, either, because it fails to work the anaerobic functions of the body; once you’re done and your heart rate is back to normal, your metabolism runs just as it did before you got on the treadmill. So you basically wasted 45 minutes stressing your body out and risking injury, only to eat the calories back and have little change in your metabolism to show for it. Impressive.
So, What Is Interval Training, and Why Should I Try It?
Interval training is exactly what it sounds like: different exercises done in intervals with varying levels of intensity. An example of a solid interval training session would include three back-to-back rounds of the following: 3 minutes of strength training, 2 minutes of cardio and 1 minute of core work. This is the model that my Jillian Michaels DVD follows, and the benefit is that you’re working in an aerobic and anaerobic capacity. This is important, because aerobics work your slower, oxygen-consuming functions, whereas anaerobics work the faster, muscle-building functions of the body, a two-for-one deal that’s hard to beat.
The thing that may scare some people away from interval training is that it’s an extremely intense workout, demanding most of your energy and muscular strength, a far-reach from the comfortable 45-minute jog that allows you to maintain a slow but steady pace until the end. Technically, it’s called HIIT, or High-Intensity Interval Training, and it’s done less frequently than conventional exercise (2-3 times a week, instead of 4-5 times a week for regular exercise). As you use HIIT to train, you may find yourself so out-of-breath at the end of you workouts that you’re not sure how you can continue. Before you give up, let me list a few of the benefits:
- It’s faster and more efficient, making it easier for those of us who are busy to get in a good workout.
- Your metabolic processes will change in your favor, enabling your body to continue burning fat at a higher rate up to 24 hours after the fact.
- There is less damage to the heart than found in conventional cardio, and it helps you build endurance over shorter periods of time.
- You build muscles and lose fat at the same time, making it easier to gain that toned physique everyone aims for.
- You don’t have to buy anything extra, except maybe some hand weights and a pair of good running shoes.
- Results happen a lot more quickly compared to chronic cardio; two months of HIIT return greater fat loss and greater increases in muscle than two months of slaving away on the treadmill. This is because you burn more calories during your workouts, you continue to burn calories after the fact, and you’re strengthening your fast- and slow- muscles through strength training and short bursts of intense exercise.
I’ve just recently begun my journey into the world of HIIT, but I know from experience (track and field in high school) that long periods of cardio stress have hurt my body in more ways than one; as a runner, I suffered from bruised bones on my feet, shin splints, periods of illness and weakness resulting from over-working myself. I’ve still got some problems with my knees that are the result of my years of hitting the pavement for miles at a time.
Now, after only two weeks of starting interval training, I can already feel the muscles in my body toning up and the fat loss accelerating, as evidenced by my ability to fit into a rather slim pair of jeans I purchased only a month or so ago while still struggling with my weight.
I’d love to hear about your successes with HIIT–how did you start out, which routines worked best for you, and what kinds of results have you gotten from making the change? Let me know in the comments!