By Dr. Mercola

Time and again, fitness research reminds us that physical activity is one of the best preventive “drugs” available, capable of improving or even reversing a number of common ailments, including mental health problems, diabetes and heart disease.1

For example, one meta-review2 of 305 randomized controlled trials comparing the effectiveness of exercise and drug interventions on mortality outcomes was unable to detect any statistical differences between exercise and medications for prediabetes and heart disease. In other words, exercise can replace most drug treatments for these conditions. Even cancer patients stand to benefit tremendously from exercise, extending their lifespan and lowering their risk of recurrence.

Exercise has also been proven to be key for longevity, which isn’t particularly surprising considering it helps correct the metabolic problems underlying most chronic diseases that lead to an early grave. The question is what type of exercise is the most effective and how much exercise is “enough?” There are no hard and fast rules here, but studies do offer some valuable clues and guidelines.

As a general rule, something is better than nothing, and one of the foundational fitness guidelines is to get regular movement throughout your waking hours. In other words, avoiding sitting as much as possible is key, as the simple act of bearing weight on your legs helps stimulate a biochemical cascade that benefits your health.

Over and beyond that, the research is quite clear on the type of exercise that is the most effective — both in terms of delivering powerful health benefits and being time-efficient — and that is high-intensity interval training (HIIT).

Study Investigates Exercise Dosage Required for Longevity

According to one of the most recent studies looking at what it takes to lower your mortality risk, mini-bursts of activity are as effective for extending your life as longer, dedicated fitness regimens. As noted by Forbes,3 “The life-extending benefits of physical activity may add up, regardless of whether you do it in one concentrated session or short bursts throughout the day.”

For this study,4,5 published in the Journal of the American Heart Association, the team analyzed data from 4,840 American adults aged 40 and older who participated in the National Health and Nutrition Examination Survey. The exercise portion of this survey required participants to wear accelerometers around their waist for up to a week to track their physical activity levels.

The data recorded by the device allowed the researchers to compile detailed information about the amount of moderate and vigorous activity each participant was engaged in. The goal of the investigation was to ascertain “whether moderate‐to‐vigorous physical activity needs to be accumulated in bouts to provide mortality benefits.” As noted by the authors:6

“The 2008 Physical Activity Guidelines for Americans recommends that adults accumulate at least 150 min/wk of moderate or 75 min/wk of vigorous‐intensity physical activity for substantial health benefits. The guidelines also direct that activity be performed in bouts of at least 10 minutes.

The 10‐minute bout criterion originated in 1995 and was intended to provide flexibility in achieving the recommended dose. This messaging shift emphasized the importance of accumulating a total volume of moderate‐to‐vigorous physical activity and has remained a central feature of guidelines as they evolved. Surprisingly, evidence supporting a minimum bout of 10 minutes is limited.”

Total Daily Activity Regardless of Bout Duration Provides Valuable Benefits

Activity measurements included the total number of minutes spent in activity and the number of high-intensity bursts lasting longer than five and 10 minutes respectively (allowing for interruptions of up to two minutes). Death records were also reviewed to see how many people died during the 6.6-year follow-up. As noted in the featured article:7

“With all of this information, the researchers could determine whether there was any association between the total amount of physical activity and death and whether this association was different when you only counted bouts of moderate-to-vigorous physical activity that was greater than five minutes or 10 minutes in duration.”

What they discovered was that the more moderate-to-vigorous physical activity you get, the lower your likelihood of death, regardless of whether that activity is done in bouts lasting a certain number of minutes or done in longer, continuous sessions. At the low activity end, those who got at least 30 minutes of moderate-to-vigorous physical activity per day had a mortality risk that was one-third lower than those who remained sedentary.

(This finding echoes previous results from one of the largest studies8 ever done, which found those who got 150 minutes of moderate exercise per week (just over 21 minutes per day) lowered their risk of death by 31 percent during the 14-year study period, compared to those who did not exercise.)

Mortality rates got even lower from there. Those who got between 60 and 99 minutes of moderate-to-vigorous activity per day lowered their risk of death by about 50 percent, and those who stayed active for at least 100 minutes or more each day were 75 percent less likely to die. Again, a key finding was that it didn’t really matter if this activity was done in short bursts throughout the day or in longer concentrated sessions. As explained by the authors:

“Sporadic and bouted moderate‐to‐vigorous physical activity was similarly and strongly associated with mortality risk. Mortality risk reductions associated with moderate‐to‐vigorous physical activity are independent of how activity is accumulated … The key message … is that total physical activity (i.e., of any bout duration) provides important health benefits.

Practitioners can promote either long single or multiple shorter bouts of activity in advising adults how to progress toward 150 min/wk of moderate‐to‐vigorous physical activity. This flexibility may be particularly valuable for individuals who are among the least active and likely at greater risk for developing chronic conditions.”

Limiting Your Sitting Is a Foundational Aspect of Good Health

Since it’s the overall amount of physical activity each day that brings you the greatest rewards — at least in terms of life extension — you can accumulate “fitness points” either by doing burst-type exercises several times a day, or simply walking and moving about a lot.

In this study, no distinction was made between intentional exercise such as taking a brisk walk and unintentional activity such as vacuum cleaning or walking up a flight of stairs. Just about any physical activity counts. In earlier research, the greatest longevity benefits were in fact reaped by those who primarily walked for an hour or more each day.9

This makes sense when you consider that chronic sitting has health and mortality risks similar to smoking, raising both your risk of lung cancer and all-cause mortality by about 50 percent. Importantly, it elevates your risk for an early death independently of your fitness and other lifestyle habits.

It’s ok to sit some, and you don’t have to go under an hour like I have, but ideally you’ll want to limit your sitting to three hours or less, and aim for 10,000 steps a day, over and above your scheduled workout. A fitness tracker can be a helpful tool to monitor your progress and ensure you’re hitting your mark.

Simple Ways to Get More Activity Into Your Daily Life

That said, it’s worth stating that HIIT has been shown to have physical benefits that surpass mere walking — such as boosting human growth hormone (HGH) and building strength and stamina — but at least in terms of reducing your risk of death over the long-term, staying active, in whatever way works for you, is the most important factor. The great news is there are countless ways of getting more movement into your daily life. Here are a handful of suggestions:

  • Walk or bicycle whenever possible rather than driving your car. Walking can easily be turned into a high-intensity bout exercise by intermittently quickening your pace
  • Take every opportunity to get out of your office chair and move. For example, deliver a message to a colleague in person rather than sending an email or test (provided they’re within walking distance); stand up when talking on the phone; conduct walking meetings or standing meetings
  • Opt for less convenience. Take the stairs instead of the elevator; park further away from the store entrance; use a push mower rather than a sit-down mower to cut your grass; rake your own leaves and your own garden rather than paying someone to do it
  • Get active with your children; play ball, Frisbee or any other activity the whole family enjoys

Science-Backed 7-Minute Routine

In related news, science correspondent Erin Brodwin writes10 about her experience with the Johnson & Johnson Official 7-Minute Workout app,11 designed by exercise physiologist Chris Jordan, who has worked as a fitness consultant for the U.S. Air Force. Each HIIT session consists of 12 exercises done in quick succession.

“The first four exercises I did — 30 seconds each of jumping jacks, wall sits, pushups and crunches, with 10 seconds of rest in between — were easy,” Brodwin writes.12 “But by the time I got to planks, I was starting to feel a bit winded. At this point, I’d also done stepups onto a chair, squats and tricep dips …

Next came running in place while lifting my knees as high as I could, lunges, alternating pushups and rotations (raising one arm in the air while balancing on the other), and side planks … I’m satisfied overall with the 7-Minute Workout, and I’ve been doing it as an addition to my regular yoga routine every so often. But don’t take my word for it — it doesn’t take long to try it out yourself.”

Optimize Your Fitness With HIIT

While there are many conflicting views on fitness, I believe an ideal approach focuses on balance and variety. So, while daily nonexercise movement lays the foundation for good health, more intense exercise is needed to really optimize physical fitness and maximize the health benefits you can get from all the other positive lifestyle strategies you engage in.

A growing body of clinical research maintains that the ideal fitness regimen is one that mimics the movements of our hunter-gatherer ancestors, as these movement patterns are what your body is hard-wired for. This includes:

  • A variety of physical activities performed regularly (including walking, weight training, burst-type cardio and stretching). As a general rule, HIIT would be performed once or twice a week and weight training at least twice a week
  • Alternating more intense activity days with less active days
  • Ample time for rest after physical exertion

Part of what makes HIIT so beneficial for your body composition and general fitness and longevity is that it engages more muscle tissue than conventional aerobic cardio exercise. You have three different types of muscle fibers: slow, fast and super-fast. Only the super-fast muscle fibers will impact your production of HGH, also known as “the fitness hormone,” which is key for strength, health and longevity, and HIIT is the only way to effectively engage these super-fast fibers.

If you’re over the age of 30, especially if you lead an increasingly sedentary lifestyle, you’ve likely entered a phase known as somatopause (age-related growth hormone deficiency). As your HGH levels decrease, your levels of insulin-like growth factor-1 also decrease. This is another important part of what drives your body’s aging process.

Another tremendous benefit of HIIT is that it produces anti-inflammatory myokines in your muscles, which very effectively reverses metabolic syndrome by increasing insulin sensitivity, glucose utilization inside the muscle, and the liberation and burning of fat from adipose cells. Myokines also act as chemical messengers that inhibit the release and effect of inflammatory cytokines produced by your body fat. They also significantly, via an inhibitory effect, reduce body fat irrespective of calorie intake.

Four-Minute Exercise Three Times a Day May Be an Ideal Alternative

The take-home message here is simply to remain as active as you can, all day long. Whenever you have a chance to move and stretch your body in the course of going about your day, do so. That said, there’s no doubt that an ideal fitness regimen requires a little more effort. The good news is HIIT is extremely time-efficient. Aside from the 7-minute routine highlighted above, there are many others, most of them requiring mere minutes.

My current favorite is the Nitric Oxide Dump, a four-minute exercise that can improve mitochondrial health and slow down age-related muscle decline. Nitric oxide (NO) is a soluble gas stored in the lining of your blood vessels (endothelium). It’s produced inside your endothelial cells from the amino acid L-arginine, where it acts as an important signaling molecule throughout your body.

Along with promoting healthy endothelial function and heart health, NO supports healthy blood flow by helping your veins and arteries dilate. This, in turn, allows vital oxygen and nutrients to flow freely throughout your body. NO also plays a protective role in your mitochondrial health, the energy storehouse of your cells, responsible for the utilization of energy for all metabolic functions.

When you exercise, it takes only 90 seconds for your blood vessels to run out of stored NO, triggering the process of making more. This is why working your major muscle groups for 90 seconds can be so effective, despite appearing limited.13 The Nitric Oxide Dump workout was developed by Dr. Zach Bush based on this premise.

Less really is more when you know how to harness your body’s NO-generating powers! Short bursts of high-intensity activity are the most effective. It’s also important to wait at least two hours between sessions because that’s how long it takes for NO to synthesize in your body for subsequent release. I recommend doing the Nitric Oxide Dump three times a day. And, since you don’t need any equipment, you can do it just about anywhere. For a full demonstration, see the video.