Just One Session of HIIT Might Help Stop Cancer Cells From Growing

New research provides further evidence that staying active could play a serious preventive role.

  • Exercise has been linked to a reduced risk of certain kinds of cancer. And now, new research suggests that high-intensity interval training, or HIIT, may help thwart the growth of cancer cells, too.
  • Researchers determined that even a single session of HIIT was effective at reducing the growth of colon cancer cells.
  • While the study was performed in cancer survivors, researchers believe the same findings may apply to others as well.


Consistent, long-term physical activity has been linked to reduced risk for several types of cancer, thanks to the way exercise reduces inflammation, improves immune system function, and lowers levels of certain hormones related to cancer development.

But you don’t need to log years of effort to get the cancer-fighting benefits: A new study published in the Journal of Physiology suggests that even a single session of high-intensity interval exercise may significantly slow the growth of colon cancer cells.


Researchers recruited male colorectal cancer survivors, and had them complete either one HIIT session or do HIIT training regularly. The single-session group did a 10-minute warmup before four rounds of cycling, each for four minutes, with three minutes of recovery time in between. The short-term training group did this protocol three times a week for a month.

Immediately before and after each exercise session, researchers collected blood samples. They replaced the serum—what’s left once red blood cells are removed—of cancer cells grown in a lab with the serum from the participants to see how exercise affected the cell growth.


Serum collected before exercise didn’t reduce colon cancer cell growth, but the serum taken after that single cycling session? That squashed the growth of the cancer cells immediately, suggesting that HIIT may change the environment of the cells, so they are less likely to grow unchecked.

The serum collected from the training group showed no significant differences, meaning they didn’t have more cancer-stopping power compared to the single-session group.


Researchers found there were elevations in some inflammatory markers, known as cytokines, immediately after exercise, and hypothesized that this is what played the biggest role in cell growth reduction, according to lead researcher James Devin, Ph.D., an exercise physiologist at the University of Queensland.

“During exercise, muscle becomes a primary source for releasing inflammatory cytokines markers, known as myokines,” he told Runner’s World. “We know that higher intensity exercise promotes a much greater myokine response compared to moderate intensity exercise.”

Although the recent study involved only colon cancer survivors, Devin said that the reduction in cancer cell growth is likely not specific only to those who’ve had cancer before. He noted that other research using similar techniques and serum from healthy individuals has found reductions in the growth of prostate cancer cells.

“There will always be subtle differences in how individuals respond to exercise,” he said. “And we are still a long way from understanding how these responses observed in the laboratory may influence human colorectal tumors. But the current results are very exciting, and suggest the acute effects following every single session of exercise are of great importance.”



byELIZABETH MILLARD

How Timing Your Workout Can Help Calm Your Raging Appetite

It won’t mess with your sleep, either.
  • High-intensity interval exercise is known for a whole host of health benefits, but conventional wisdom has held that if you perform it too close to bedtime, it may mess with your sleep.
  • Now, a new study finds that HIIT will not hinder your sleep—and it may even help blunt your appetite after the session, too.
  • Because everyone’s body clock is different, the exact timing of when is best to exercise is hard to say.

You know that high-intensity interval training (HIIT) is great for your body. Not only does incorporating HIIT workouts into your routine help boost your running speed and power, but it has also been shown to help you lose weight and protect your heart, too.

Here’s one more to add to the list: HIIT may be able to curb your appetite, too. According to a new study published in the journal Experimental Physiology, HIIT—especially when done later in the day as opposed to in the morning—can also quell your cravings when it comes to food. 
The small study out of Charles Sturt University in Australia included 11 middle-aged men whose peak oxygen consumption (VO2peak) and sleeping and eating patterns were recorded a week before any experimental testing was done. Afterwards, they participated in three trials of 30 minutes of high-intensity interval exercise (HIIE), which involved six one-minute high-intensity cycling sprints at 100 percent of their VO2peak with four minutes of rest at 50 percent of their VO2peak in between each sprint. 

Each trial lasted three days each—the first was done in the morning, the second was done in the afternoon, and the third was done in the evening. There were five days of recovery between each trial. 

The results? Participants’ levels of the appetite-stimulating hormone ghrelin were actually reduced in the afternoon and evening trials.

One reason may be because peak power output was slightly higher during the afternoon and evening sprints than in the morning. The researchers believe that greater power output leads to a greater reduction in the signals governing your appetite.

Additionally, among the workout times, there were no significant differences in the total sleep duration of the participants or how well they slept. Translation: Those who sweated at night didn’t sleep any worse. So the age-old adage to avoid exercise—especially at a high intensity—in the hours before going to sleep might not be true.

In fact, the researchers believe that HIIT may actually help you sleep, since it triggers a larger release of the stress hormone norepinephrine, lead author Penelope Larsen, Ph.D.(c) of Charles Sturt University’s School of Exercise Science, Sport, and Health. That’s important, since it may aid in non-REM sleep—or deep sleep—and delay REM sleep, where your breathing becomes faster and irregular, and your heart rate and blood pressure increase to levels that are similar to when you’re awake. As a result, you’ll feel more well rested.

However, Larsen noted that while the evening portion of the experiment was done between 6 p.m. and 8 p.m., “the ‘ideal’ time [to work out] before bed would be different for everybody,” since no one’s body reacts exactly the same. Depending on your sleep-wake cycle, the best time for you may be slightly earlier or later. Just make sure your workout is not encroaching on your normal bedtime, so that you continue to get the same amount of sleep as you always do.

Another important note: Because study participants were exclusively middle-aged men, it’s hard for Larsen and her colleagues to say for sure whether or not other populations would respond the same way to evening HIIT.

“Previous research has shown that for young adults (predominantly men), evening high-intensity exercise can also be performed safely without detriment to subsequent sleep,” she said. “However, given hormonal changes experienced throughout the monthly cycle by women of a similar age group, or young adult women, sleep responses may be different to the findings of the current study.”

DANIELLE ZICKL Associate Health & Fitness EditorDanielle specializes in interpreting and reporting the latest health research and also writes and edits in-depth service pieces about fitness, training, and nutrition

Rhythmic Breathing

In my early days as a runner, I, like most, didn’t give any thought to my breathing. But after dealing with several injuries, I went digging into physiology research to find a solution to my predicament. Eventually I came across an article called “Breath Play,” by Ian Jackson, a coach and distance runner, which related breathing cycles with running cadence. Later I found a study by Dennis Bramble, Ph.D., and David Carrier, Ph.D., of the University of Utah, explaining that the greatest impact stress of running occurs when one’s footstrike coincides with the beginning of an exhalation. This means that if you begin to exhale every time your left foot hits the ground, the left side of your body will continually suffer the greatest running stress.

Hmm. My most frequent injury was to my left hip flexor. So I began to think: What if I could create a pattern that coordinated footstrike and breathing such that I would land alternately on my left foot and then right foot at the beginning of every exhale? Perhaps I could finally get healthy. It was worth a try.

I developed a pattern of rhythmic breathing and began using it between my junior and senior years of college. I also trained for and ran my first marathon the winter before graduating and finished in a respectable 2:52:45.

I continued to work on a rhythmic breathing method of running while pursuing my master’s degree in physical education and exercise physiology, during which time I trained for my second marathon. I honed in on a the three-step method for faster running during that second marathon and ran an incredibly even 2:33:29. Now I knew I could manage my effort through rhythmic breathing with a great deal of success. Since then, I’ve taught this method to the many runners I’ve coached over the years. It can work for you, too.

What Is Rhythmic Breathing?

Rhythmic breathing can play a key role in keeping you injury-free, as it has for me. But to understand how that can happen, first consider some of the stresses of running. When your foot hits the ground, the force of impact equals two to three times your body weight, and as research by Utah’s Bramble and Carrier showed, the impact stress is greatest when your foot strikes the ground at the beginning of an exhalation. This is because when you exhale, your diaphragm and the muscles associated with the diaphragm relax, creating less stability in your core. Less stability at the time of greatest impact makes a perfect storm for injury.

So always landing on the same foot at the beginning of exhalation compounds the problem: It causes one side of your body to continuously absorb the greatest impact force of running, which causes it to become increasingly worn down and vulnerable to injury. Rhythmic breathing, on the other hand, coordinates footstrike with inhalation and exhalation in an odd/even pattern so that you will land alternately on your right and left foot at the beginning of every exhalation. This way, the impact stress of running will be shared equally across both sides of your body.

An analogy would be if you loaded a backpack down with books and then slung it over your right shoulder. With all this weight on one side of your body, you’d be forced to compensate physically, placing more stress on one side. But if you were to slip that same heavy backpack over both shoulders, the load would be distributed evenly. You’d put your body in a position to better manage that stress, and your back would stay healthy.

It stands to reason that if one side of the body relentlessly endures the greater impact stress, that side will become worn down and vulnerable to injury. Rhythmic breathing allows a slight rest to both sides of the body from the greatest immediate impact stress of running. But there’s more to it than a pattern of footstrikes, exhales, and inhales that keeps you injury-free. Rhythmic breathing also focuses your attention on your breath patterns and opens the way for it to become the source of how you train and race.

The Breathing Benefits of Rhythmic

Attention to breathing has a long history in Eastern philosophy. Dennis Lewis, a longtime student of Taoism and other Eastern philosophies, teaches breathing and leads workshops at venues including the Esalen Institute and The Kripalu Center for Yoga and Health. In his book, The Tao of Natural Breathing, Lewis shares the following Taoist belief: “To breathe fully is to live fully, to manifest the full range of power of our inborn potential for vitality in everything that we sense, feel, think, and do.”

In Hinduism, yoga teaches pranayama—breath work. Prana means breath as a life-giving force: The work of breathing draws life-giving force into the body. And that work is accomplished through diaphragmatic breathing, or belly breathing, which means that as you inhale, you contract the diaphragm fully to allow maximum volume in the thoracic (chest) cavity for maximum expansion of the lungs and maximum intake of air. Rhythmic breathing does the same thing, drawing the breath—the life force—into the body through controlled, focused diaphragmatic breathing. Through rhythmic running we breathe fully and, as the Taoist would say, realize our vitality.

Rhythmic breathing also creates a pathway to a deep centeredness. Practitioners of every style of yoga, martial arts, relaxation, and meditation use breath work to connect mind, body, and spirit. In the martial arts, this inner connection and centeredness allows more immediate and precise control of the physical body.

The same can be accomplished in running through rhythmic breathing. You achieve centeredness first by focusing your mind on fitting your breathing to an optimal footstrike pattern. Then your awareness of breathing links mind and body and creates a smooth pathway to gauging the effort of running. Rhythmic breathing helps you feel your running, and that ability to feel your running allows you immediate and precise control.

Yoga teaches that controlling your breathing can help you control your body and quiet your mind. When we allow ourselves to become distracted by trying to match our running effort to a pace we’ve defined with numbers on a watch, we break that mind/body connection. We open up a gap where stress and tension can enter. And we create a disturbance in the flow of running that hinders our success and enjoyment. Rhythmic breathing is calming, and awareness of breathing draws your focus toward calm. It allows you to remain as relaxed as possible, quieting any stress in the body that could inhibit performance. And if you should feel a twinge of tension or discomfort, you can mentally “push” it out of the body as you exhale.

During moderate or long runs, rhythmic breathing allows you to slide easily into an effort and pace at which everything glides on autopilot. Your breathing is comfortable, your cadence is smooth and even, and the rhythm of both combines for that “harmonious vibration with nature.”

How to Breathe While Running

Before learning the rhythmic patterns that will take your running to a new level, you must first become a belly breather, that is, learn to breathe from your diaphragm. When you inhale, your diaphragm contracts and moves downward, while muscles in your chest contract to expand your rib cage, which increases the volume in your chest cavity and draws air into your lungs. Working your diaphragm to its fullest potential allows your lungs to expand to their greatest volume and fill with the largest amount of air, which of course you need for your running. The more air you inhale, the more oxygen is available to be transferred through your circulatory system to your working muscles. Many people underuse their diaphragm, relying too much on their chest muscles and therefore taking in less oxygen, which is so important to energy production. The other downside of breathing from your chest is that these muscles (the intercostals) are smaller and will fatigue more quickly than your diaphragm will. To rely less on your chest muscles to breathe, you’ll want to train yourself to breathe from your belly, that is, with your diaphragm. Practice belly breathing both lying down and sitting or standing, since you should be breathing diaphragmatically at all times—whether you’re running, sleeping, eating, or reading a book. Here’s how to learn the technique:

Lie down on your back.

Keep your upper chest and shoulders still.

Focus on raising your belly as you inhale.

Lower your belly as you exhale.

Inhale and exhale through both your nose and mouth.

Establish a Pattern

Many runners develop a 2:2 pattern of breathing, meaning they inhale for two footstrikes and exhale for two footstrikes. Some breathe in for three steps and exhale for three steps. Both have the same result—your exhale is always on the same side. Breathing patterns that extend the inhale will shift the point of exhalation alternately from left to right or from right to left, from one side of the body to the other. The singular point of all rhythmic breathing patterns is this: Exhale on alternate footstrikes as you run. You never want to continually exhale on the same foot.

The rhythmic breathing patterns I recommend call for a longer inhale than exhale. Why the longer inhale? Your diaphragm and other breathing muscles contract during inhalation, which brings stability to your core. These same muscles relax during exhalation, decreasing stability. With the goal of injury prevention in mind, it’s best to hit the ground more often when your body is at its most stable—during inhalation.

Let’s start with a 5-count or 3:2 pattern of rhythmic breathing, which will apply to most of your running. Inhale for three steps and exhale for two. Practice first on the floor:

1. Lie on your back with your knees bent and feet flat on the floor.

2. Place a hand on your belly and make sure that you are belly breathing.

3. Breathe through your nose and your mouth.

4. Inhale to the count of 3 and exhale to the count of 2. You might count it this way: “in-2-3,” “out-2,” “in-2-3,” “out-2,” and so forth.

5. Concentrate on a continuous breath as you inhale over the 3 counts and a continuous breath as you exhale.

6. Once you become comfortable with the inhale/exhale pattern, add foot taps to mimic walking steps.

EXHALE ON ALTERNATE FOOTSTRIKES AS YOU RUN. YOU NEVER WANT TO CONTINUALLY EXHALE ON THE SAME FOOT.

When you feel confident that you have the 3:2 pattern down, take it for a walk. Inhale for three steps, exhale for two, inhale for three steps, exhale for two. Finally, of course, try out your rhythmic breathing on a run—inhaling for three footstrikes and exhaling for two.

A few key points: Inhale and exhale smoothly and continuously through both your nose and mouth at the same time. If it seems difficult to inhale over the full three strides, either inhale more gradually or pick up your pace. And lastly, do not listen to music while learning to breathe rhythmically. The beats of the music will confuse the heck out of you.

Now Go Faster

You will find that the 3:2 breathing pattern works well when you are running at an easy to moderate effort, which should make up the majority of your running. Let’s say, however, you are out for a comfortable five-miler and about midway, you come upon a hill. Because your muscles are working harder, they need more oxygen. Your brain also signals to your respiratory system that you need to breathe faster and deeper. You reach a point running up the hill when you can no longer comfortably inhale for three steps and exhale for two. It’s time to then switch to a 3-count, or 2:1, rhythmic breathing pattern: Inhale for two steps, exhale one, inhale two steps, exhale one. You’re breathing faster, taking more breaths per minute, and this odd-numbered breathing pattern will continue to alternate the exhale from left foot to right, dispersing the impact stress of running equally across both sides of your body. Once you’ve crested the hill and are running down the other side, you might continue in this 2:1 pattern until your effort and breathing have recovered and you slip back into your 3:2 cadence.

When you begin breathing rhythmically, it’s a good idea to consciously monitor your breathing patterns, although it’s not necessary to do so throughout your entire run. Focus on your breathing when you start out, evaluate your breathing as your effort changes—such as when you climb a hill—and then simply check in at random intervals to make sure that you haven’t fallen into a 2:2 pattern. Over time, the 3:2 and 2:1 rhythmic patterns will become automatic.

Not surprisingly, the 2:1 breathing pattern also comes into play during speed training and racing. I originally began to use rhythmic breathing as a way to run injury-free. When I realized it was working with easy and moderate runs, I was afraid to break away from it during hard training workouts, and through trial and error learned to follow a 5-count rhythmic breathing pattern during an easy run or a long run and a 3-count rhythm for interval training and racing. Rhythmic breathing allowed me to complete my last year of competitive college running with moderate success. It would allow me to go on to qualify for four Olympic Marathon Trials and to set a PR of 2:13:02 in the marathon.

Finish Strong

On your next run, do some “breath play.” Start out in a 3:2 breathing pattern at a very easy effort—your warmup. This is a comfortable pace at which you could converse easily with a running partner. How does it feel? Notice the depth and rate of your breathing. After 10 minutes, pick up your pace just a bit to an effort that requires you to breathe noticeably deeper while you continue to run within the 3:2 breathing pattern. You should still be able to talk with your running buddy, but you’ll be glad for those periods in the conversation when you get to just listen. Run at this pace for a few minutes and tune into your body, feel your breathing—your lungs expanding, your belly rising.

Now pick up your pace even further while holding the 3:2 breathing pattern. At this point, you’ll be breathing about as deeply as you can, which makes the effort uncomfortable. You are now experiencing a difficult rhythmic breathing effort. And you’d rather not. So you convert to a 3-count, or 2:1, breathing pattern—inhaling for two steps and exhaling for one. You’re taking more breaths per minute, in a pattern that still distributes the impact stress equally across both sides of your body. Notice that the effort of breathing becomes comfortable again. You will be able to talk some. Running will feel comfortably fast again. Spend a few minutes at this pace and effort, focusing on your breathing and on your body.

Now increase your pace, forcing deeper breathing. You are running at a serious level that does not allow you to talk. Up the pace again. You are breathing about as deeply as you can, but the difference is that you are also breathing about as fast as you can. And, of course, your pace is much quicker. You can’t hold this effort for very long. It might feel like you have no place else to go, but you do—to a pattern of 2-1-1-1, which allows you to breathe faster. You switch to the following: Inhale for two steps, exhale for one, inhale for one, exhale for one; inhale for two steps, exhale for one, inhale for one, exhale for one; and so forth. This is the effort you will put forth for your kick at the end of a race. Or you can use this to help you crest a steep hill during a race.

Once you’ve tested the 2-1-1-1 pattern, slow down, ease up, and allow your breathing to return gradually to a comfortable 3:2. The more you use rhythmic breathing in training and racing, the easier and more automatic it becomes.

As you use rhythmic breathing in your training and racing and tune in to your breathing efforts and paces, you will learn to run from within, in complete harmony with your body. You will discover the natural rhythms of your running, which will lead you to improved performances but also to experience the pure joy of running.

This article was adapted from Running on Air: The Revolutionary Way to Run Better by Breathing Smarter, by Budd Coates, M.S., and Claire Kowalchik (Rodale, 2013). The book teaches how to use the principles and methods of rhythmic breathing across all levels of effort and includes training plans for distances from 5K to the marathon, as well as strength-training programs and stretching workouts.