Sitting Is the New Smoking Disease
The 2012 Comprehensive Physiology article highlighted the fact that 95% of adults in the United States do not meet the minimum guideline for physical activity, which, as explained earlier, is 150 minutes of somewhat hard exercise throughout the week. Why is it such a struggle for the majority of Americans to attain 30 minutes of somewhat hard physical activity at least 5 days per week? Some scientists explain that there has been a steep decline in physical activity during the last several decades due to our reliance on technology, including automobiles, computers, televisions, smartphones, tablets, and energy-saving devices. Our new technologies have advanced travel, communication, education, research, business, and medicine, but have also contributed to a massive spike in physical inactivity (what we scientists refer to as “sedentary behavior”). People in developed societies throughout the world are spending greater amounts of time in activities that not only limit physical activity, but also require prolonged sitting. Schools, homes, worksites, and public spaces are built in ways to minimize human movement and promote sitting. When it comes to health, many wellness professionals now claim excessive sitting is akin to the smoking disease of yesteryear for its long-term health consequences.
Life is motion; we are a species designed to regularly move. Movement is vital for health and optimal aging. Accordingly, inspiring you to move more is a major goal of this book, and my START MOVING NOW! program, which is based on articles I’ve written, will help you combat sedentary behavior. My goal for most people I work with is to move more during their waking day. The benefits of this kind of lifestyle change are plain—and supported by research. In fact, a June 2016 article in the journal Diabetes Care showed that people who break up their waking days with movement are likely to reduce the risk of diabetes and cardiovascular complications. I encourage you to start moving more every day, and keep moving for the rest of your sure-to-be-vibrant life.
A New Fitness Team Is Forming
The medical community is now beginning to work closely with fitness professionals to help encourage people to get physically active. For its part, the American College of Sports Medicine has developed a new medical campaign promoting physical activity and exercise known as Exercise is Medicine (EIM). EIM is an international health initiative that encourages healthcare providers and primary care physicians to include physical activity when prescribing treatment plans for their patients. Many of these primary care physicians also refer their patients to credentialed exercise programs and certified exercise professionals. This collaboration between the medical community and fitness pros sends an invaluable message to everyone, regardless of their age: start moving, keep moving, and make exercise an essential part of your daily life. Remember, “Inch by inch, it’s a cinch.”
Chapter 2
What Is High-Intensity Interval Training (HIIT)?
I am regularly invited to fitness conferences around the world to discuss the physiological merits of HIIT workouts and how to design HIIT programs. It is a big focus of my professional life, so I’d like to take this opportunity to explain it to you in more detail.
HIIT is a system of cardiovascular training that involves alternating between high- and light- intensity intervals of exercise of varying lengths of time. The high-intensity intervals (often referred to as work periods) may range from 5 seconds to 8 minutes long, and are performed at a self-regulated intensity ranging from comfortable-but-challenging to more challenging. The light-intensity intervals, called the recovery periods, are self-paced periods of exercise at a light-to-moderate intensity. When we speak of intensity, we are talking about the level of exercise exertion, or how hard you exercise. Each workout begins with a gradual warm-up that prepares the body for the following workout. This continues into the HIIT part of the workout, where alternating work and recovery intervals total a combined 10 to 20 minutes—or longer, if you are endurance-trained. Every HIIT workout concludes with a total body cooldown to return the body’s heart rate, breathing rate, blood flow, and temperature back to a pre-exercise level.
In the book introduction I stated that true HIIT workouts are cardiovascular workouts. All of the wonderful health, disease prevention, and fat loss benefits are based on these types of workouts. Plus, all of the workouts in this book are adapted from actual studies that show these fabulous outcomes. Please note that the word “high-intensity” is a buzzword in the fitness industry for any workout that is very challenging. There are countless high-intensity workouts in the fitness industry (such as boot camp and body blast), however not all of them are actual HIIT programs.
Why Is HIIT so Popular?
Recently, interest in HIIT has grown enormously due to the widespread popularity of exercise programs, including P90X, Insanity, and CrossFit, all of which include aspects of HIIT. Millions of exercise buffs have found that alternating hard-intensity intervals of exercise with light-intensity intervals of recovery leads to enjoyable fitness gains in less time. In fact, in a 12-week 2017 study published in the Journal of Diabetes Research, it took obese sedentary women half the time to lose the same amount of body fat through HIIT training as it took them to lose it through traditional aerobic exercise. Another advantage of HIIT is the ease with which it can be modified for people of all fitness levels and health conditions. HIIT has generated a great deal of support with special populations, such as overweight individuals and those with clinical conditions like type 2 diabetes and cardiovascular disease. HIIT workouts can be performed with every kind of exercise modality, including cycling, walking, swimming, aqua training, elliptical striding, and in many group exercise classes. Also, HIIT workouts provide similar, and perhaps better, fitness benefits than continuous moderate-intensity aerobic workouts—what we call “steady-state workouts”—but in shorter periods of time.
Even more appealingly, HIIT workouts tend to burn more calories than traditional workouts, particularly after the workout; yes, that is correct—after the workout. Let me explain further. During the time period immediately following a workout, the body experiences an exercise “afterburn,” or excess post-exercise oxygen consumption (EPOC) in exercise science terms. That’s a mouthful, so let me put it in plain words. After every workout, your body’s muscles and major systems, such as cardiovascular and respiratory, are still revved up. As a result, it takes energy to recover from exercise, and EPOC represents the energy expenditure you utilize to restore your body after your workout. So as you gradually slow down your muscles and return your body systems to pre-exercise levels, you continue to burn additional calories. This EPOC period tends to peak for about a 2-hour period after an exercise workout, though it may last up to 14 hours or longer. That means your metabolism is actually boosted for 2 or more hours after your workout.
Harder intensity workouts lead to longer EPOC periods. That’s the impressive news about HIIT and EPOC, and why I wanted to highlight it here. Because of the dynamic nature of HIIT workouts, the EPOC periods tend to be longer than they are with traditional steady-state workouts. Therefore, HIIT workouts enable you to burn more calories. This additional calorie burn helps you achieve your weight management goals, which is another benefit of HIIT training highly praised by exercise aficionados.
Interestingly—and quite satisfyingly—during EPOC the body uses primarily fat to restore the body. So, a longer EPOC means the body is burning more fat after the workout, which is another plus from your HIIT workouts.