For years, we have evidence that physical activity is associated with decreased morbidity and mortality from cardiometabolic disease. Not that we need studies to tell us that the more active we are, the better our physical and mental health.

Despite what most of us already know, only 20% of US adults meet current physical activity guidelines and 25% report no leisure-time physical activity (Source). As a father, husband, and physician with a busy practice and online presence, I get the “lack of time” factor. Time is frequently cited as a problem in multiple studies (Source; Source), with current research focusing on time-efficient strategies to promote exercise adherence and cardiometabolic health.

Recently, high intensity interval training (HIIT) has gained popularity as a novel, time-efficient exercise strategy that has been shown to improve cardiometabolic disease risk factors in a variety of populations. I think the leader in HIIT is CrossFit and I have embraced that model and have never felt better. Very “Paleo-esque”.

There are many health benefits to HIIT including:

• Studies in different populations, including type 2 diabetes, arterial hypertension, heart failure, obesity, and metabolic syndrome have demonstrated that high-intensity interval training (HIIT) (i.e., high-intensity efforts interspersed with recovery period at lower intensity) can increase endothelium-dependent dilation more effectively than traditional moderate continuous exercise. Intensity changes during exercise seems to be an important determinant of effects on endothelial function. (Source; Source; Source; Source😉
• HIIT is associated with greater improvement in physical fitness performance (VO_{2 max}) than moderate continuous training (MCT) in short-term studies. A meta-analysis involving 10 studies demonstrated that HIIT exercise provided better physical conditioning compared to MCT in subjects with established cardiovascular disease, metabolic syndrome and obesity (Source). Another recent meta-analysis found that HIIT was better than MCT in increasing VO_{2 max}in type 2 diabetes (Source). Numerous studies have established a strong association between high cardiorespiratory fitness and lower cardiovascular disease morbidity and mortality.
• HIIT appears to benefit people after a stroke in their function and cardiovascular health, according to this article summarizing 10 studies.
• HIIT can help prevent cancer AND help in cancer treatment.
• Improves immune function. Source.
• HIIT can improve vitamin D, greater than regular exercise program.
• In studies of short duration and follow-up, HIIT and cholesterol(lipid) benefits are demonstrated, but HIIT and markers of inflammation showed mixed findings. Longer-term studies are suggested to assess both lipid and inflammation parameters. As always, follow a plan and get checked and see what HIIT or any other program does for you.

How to HIIT it

1. Get a trainer. Ask to do activities outdoors when possible. Most trainers are focused on HIIT in a variety of forms. Google someone near you or find someone at the local gym. Try it. If you don’t like the person or the program, find someone else.
2. Join a Crossfit. Crossfit combines teamwork and camaraderie with physical activity. It is fun and an amazing HIIT work-out. Each day is different. Make sure the CrossFit you look at has an excellent coach.
3. Drop and give me 20. Just hit the ground doing push-ups, pull-ups, squats and lunges using your own body weight. Do shoulder raises and curls with a gallon jug of water.
4. Walk, Sprint, Walk, Sprint, Walk and so on.

Check with your doctor to make sure you are clear to perform these activities. Don’t have a doctor? Come out to Arizona and see me.